Thermal insulation products (e.g. Figs. 20, 21) are the third most important sector of the hemp industry of the EU. These are in very high demand because of the alarmingly high costs of heating fuels, ecological concerns about conservation of non-renewable resources, and political-strategic concerns about dependence on current sources of oil. This is a market that is growing very fast, and hemp insulation products are increasing in popularity. In Europe, it has been predicted that tens of thousands of tonnes will be sold by 2005, shared between hemp and flax (Karus et al. 2000).

                In North America the use of nonwood fibers in sheet fiberboard (“pressboard” or “composite board”) products is relatively undeveloped. Flax, jute, kenaf, hemp and wheat straw can be used to make composite board. Wheat straw is the dominant nonwood fiber in such applications. Although it might seem that hemp bast fibers are desirable in composite wood products because of their length and strength, in fact the short fibers of the hurds have been found to produce a superior product (K. Domier, personal communication). Experimental production of hemp fiberboard has produced extremely strong material (e.g. Fig. 22). The economic viability of such remains to be tested. Molded fiberboard products are commercially viable in Europe (e.g. Fig. 23), but their potential in North America remains to be determined.

                Utilizing the ancient technique of reinforcing clay with straw to produce reinforced bricks for constructing domiciles, plant fibers have found a number of comparable uses in modern times. Hemp fibers added to concrete increase tensile strength while reducing shrinkage and cracking. Whole houses have been made based on hemp fiber (Figs. 24, 25). In North America, such usage has only reached the level of a cottage industry. Fiber-reinforced cement boards and fiber-reinforced plaster are other occasionally produced experimental products. Hemp fibers are produced at much more cost than wood chips and straw from many other crops, so high-end applications requiring high strength seem most appropriate.

                The above uses are based on hemp as a mechanical strengthener of materials. Hemp can also be chemically combined with materials. For example, hemp with gypsum and binding agents may produce light panels that might compete with drywall. Hemp and lime mixtures make a high quality plaster. Hemp hurds are rich in silica (which occurs naturally in sand and flint), and the hurds mixed with lime undergo mineralisation, to produce a stone-like material. The technology is most advanced in France (e.g. Fig. 26). The mineralized material can be blown or poured into the cavities of walls and in attics as insulation. The foundations, walls, floors, and ceilings of houses have been made using hemp hurds mixed with natural lime and water. Sometimes plaster of Paris (pure gypsum), cement, or sand is added. The resulting material can be poured like concrete, but has a texture vaguely reminiscent of cork - much lighter than cement, and with better heat and sound-insulating properties. An experimental “ceramic tile” made of hemp has recently been produced (Fig. 27).

                In the EU and Canada, hemp has often been grown as a dual-purpose crop, i.e. for both fiber and oilseed. In France, dual purpose hemp is typically harvested twice - initially the upper seed-bearing part of the stems is cut and threshed with a combine, and subsequently the remaining stems are harvested. Growing hemp to the stage that mature seeds are present compromises the quality of the fiber, because of lignification. As well, the hurds become more difficult to separate. The lower quality fiber, however, is quite utilizable for pulp and non-woven usages.

                In North America, oilseed hemp has several advantages over fiber hemp. Hemp seed and oil can fetch higher prices than hemp fiber. Hemp seed can be processed using existing equipment, while processing of hemp fiber usually requires new facilities and equipment.

                Canada is specialized on oilseed production and processing, so that hemp oil and grain are much more suitable than fiber. Because of the extensive development of oilseeds in Canada, there is extensive capacity to produce high-quality cold-pressed hemp oil. Canada in the last 5 years has made great advances in the growing, harvesting and processing of hempseed, and indeed has moved ahead of the EU in the development of raw materials and products for the natural foods, nutraceuticals, and cosmetics industries. In the EU, a yield of 1 tonne/ha is considered good. In Canada, extraordinary yields of 1.5 tonne/ha have been realized, at least locally, although in the initial years of hempseed development in Canada yields were often less than 500 kg/ha. In 1999, the year of largest Canadian hemp acreage, yields averaged 900 kg/ha. (Ideally, hemp seed yield should be based on air dry weight - with about 12% moisture. Hemp yields are sometime uncertain, and could be exaggerated by as much as 50% when moist weights are reported.)

                Canadian experience with growing hemp commercially for the last 4 years has convinced many growers that it is better to use a single-purpose cultivar, seed or fiber, than a dual-purpose cultivar. The recent focus of Canadian hemp breeders has been to develop cultivars with high seed yields, low stature (to avoid channelling the plants’ energy into stalk, as is the case in fiber cultivars), early maturation (for the short growing seasons of Canada), and desirable fatty acid spectrum (especially gamma-linolenic acid).

                The use of Cannabis for seed oil (Fig. 36) began at least 3 millennia ago. Hempseed oil is a drying oil, formerly used in paints and varnishes and in the manufacture of soap. Present cultivation of oilseed hemp is not competitive with linseed for production of oil for manufacturing, or to sunflower and canola for edible vegetable oil. However, as noted below, there are remarkable dietary advantages to hempseed oil, which accordingly has good potential for penetrating the salad oil market, and for use in a very wide variety of food products. There is also good potential for hemp oil in cosmetics and skin-care products.

                Foreign sources, China in particular, can produce hemp seed cheaply, but imported seed must be sterilized, and the delays this usually requires are detrimental. Seed that has been sterilized tends to go rancid quickly, and so it is imperative that fresh seed be available, a great advantage for domestic production. An additional extremely significant advantage that domestic producers have over foreign sources is organic production, which is important for the image desired by the hemp food market. Organic certification is much more reliable in North America than in the foreign countries that offer cheap seeds. Whereas China used to supply most of the hempseed used for food in North America, Canadian-grown seeds have taken over this market.

                About half of the world market for hemp oil is currently used for food and food supplements (De Guzman 2001). For edible purposes, hempseed oil is extracted by cold pressing. Quality is improved by using only the first pressing, and minimizing the number of green seeds present. The oil varies in color from off-yellow to dark green. The taste is pleasantly nutty, sometimes with a touch of bitterness. Hemp oil is high in unsaturated fatty acids (of the order of 75%), which can easily oxidize, so it is unsuitable for frying or baking. The high degree of unsaturation is responsible for the extreme sensitivity to oxidative rancidity. The oil has a relatively short shelf life. It should be extracted under nitrogen (to prevent oxidation), protected from light by being kept in dark bottles, and from heat by refrigeration. Addition of anti-oxidants prolongs the longevity of the oil. Steam sterilization of the seeds, often required by law, allows air to penetrate and so stimulates rancidity. Accordingly, sterilized or roasted hemp seeds, and products made from hemp seed that have been subjected to cooking, should be fresh. The value of hemp oil from the point of view of the primary components is discussed below. In addition, it has been suggested that other components, including trace amounts of terpenes and cannabinoids, could have health benefits (Leizer et al. 2000). According to an ancient legend (Abel 1980), Buddha, the founder of Buddhism, survived a 6-year interval of asceticism by eating nothing but one hemp seed daily. This apocryphal story holds a germ of truth -- hemp seed is astonishingly nutritional.

                The quality of an oil or fat is most importantly determined by its fatty acid composition. Hemp is of high nutritional quality because it contains high amounts of unsaturated fatty acids, mostly oleic acid (C18:1 - 10-16%), linoleic acid (C18:2 - 50-60%), alpha-linolenic acid (C18:3 - 20-25%), and gamma-linolenic acid (C18:3 - 2-5%) (Fig. 37). Linoleic acid and alpha-linolenic acid are the only two fatty acids that must be ingested and are considered essential to human health (Callaway 1998). In contrast to shorter-chain and more saturated fatty acids, these essential fatty acids do not serve as energy sources, but as raw materials for cell structure and as precursors for biosynthesis for many of the body’s regulatory biochemicals. The essential fatty acids are available in other oils, particularly fish and flaxseed, but these tend to have unpleasant flavors compared to the mellow, slightly nutty flavor of hempseed oil. While the value of unsaturated fats is generally appreciated, it is much less well known that the North American diet is serious nutritionally unbalanced by an excess of linoleic over alpha-linonenic acid. In hempseed, linoleic and alpha-linolenic occur in a ratio of about 3:1, considered optimal in healthy human adipose tissue, and apparently unique among common plant oils (Deferne and Pate 1996). Gamma-linolenic acid or GLA is another significant component of hemp oil (1-6%, depending on cultivar). GlA is a widely consumed supplement known to affect vital metabolic roles in humans, ranging from control of inflammation and vascular tone to initiation of contractions during childbirth. GLA has been found to alleviate psoriasis, atopic eczema, and mastalgia, and may also benefit cardiovascular, psychiatric and immunological disorders. Ageing and pathology (diabetes, hypertension, etc.) may impair GLA metabolism, making supplementation desirable. As much as 15% of the human population may benefit from addition of GLA to their diet. At present, GLA is available in health food shops and pharmacies primarily as soft gelatin capsules of borage or evening primrose oil, but hemp is almost certainly a much more economic source. Although the content of GLA in the seeds is lower, hemp is far easier to cultivate and higher-yielding. It is important to note that hemp is the only current natural food source of GLA, i.e. not requiring the consumption of extracted dietary supplements. There are other fatty acids in small concentrations in hemp seed that have some dietary significance, including stearidonic acid (Callaway et al. 1996) and eicosenoic acid (Mölleken and Theimer 1997). Because of the extremely desirable fatty acid constitution of hemp oil, it is now being marketed as a dietary supplement in capsule form (Fig. 38).

                Tocopherols are major antioxidants in human serum. Alpha- beta-, gamma- and delta- tocopherol represent the Vitamin E group. These fat-soluble vitamins are essential for human nutrition, especially the alpha-form, which is commonly called vitamin E. About 80% of the tocopherols of hempseed oil is the alpha form. The vitamin E content of hempseed is comparatively high. Antioxidants in hempseed oil are believed to stabilize the highly polyunsaturated oil, tending to keep it from going rancid. Sterols in the seeds probably serve the same function, and like the tocopherols are also desirable from a human health viewpoint.

                Hemp seeds contain 25-30% protein, with a reasonably complete amino acid spectrum. About two thirds of hempseed protein is edestin. All eight amino acids essential in the human diet are present, as well as others. Although the protein content is smaller than that of soybean, it is much higher than in grains like wheat, rye, maize, oat and barley. As noted above, the oilcake remaining after oil is expressed from the seeds is a very nutritious feed supplement for livestock, but it can also be used for production of a high-protein flour.

                In the 1990s, European firms introduced lines of hemp oil-based personal care products, including soaps, shampoos, bubble baths, and perfumes. Hemp oil is now marketed throughout the world in a range of body care products, including creams, lotions, moisturizers, and lip balms. In Germany, a laundry detergent manufactured entirely from hemp oil has been marketed. Hemp-based cosmetics and personal care products account for about half of the world market for hemp oil (De Guzman 2001).

                One of the most significant developments for the North American hemp industry was investment in hemp products by Anita and Gordon Roddick, founders of The Body Shop, a well known international chain of hair and body care retailers. This was a rather courageous and principled move that required overcoming American legal obstacles related to THC content. The Body Shop now markets an impressive array of hemp nutraceutical cosmetics (Fig. 39), and this has given the industry considerable credibility. The Body Shop has reported gross sales of about a billion dollars annually, and that about 4% of sales in 2000 were hemp products.

                The vegetable oils have been classified by “iodine value” as drying (120-200), semi-drying (100-120), and non-drying (80-100), which is determined by the degree of saturation of the fatty acids present (Raie et al. 1995). Good coating materials prepared from vegetable oil depend on the nature and number of double bonds present in the fatty acids. Linseed oil, a drying oil, has a very high percentage of linolenic acid. Hempseed oil has been classified as a semi-drying oil, like soybean oil, and is therefore more suited to edible than industrial oil purposes. Nevertheless hemp oil has found applications in the past in paints, varnishes, sealants, lubricants for machinery, and printing inks. However, such industrial end uses are not presently feasible as the oil is considered too expensive (de Guzman 2001). Larger production volumes and lower prices may be possible, in which case hemp oil may find industrial uses similar to those of linseed (flax), soybean, and sunflower oils, which are presently used in paints, inks, solvents, binders, and in polymer plastics. Hemp shows a remarkable range of variation in oil constituents, and selection for oilseed cultivars with high content of valued industrial constituents is in progress.

                Marijuana has in fact been grown for medicinal research in North America by both the Canadian (Fig. 40) and American governments, and this will likely continue. The possibility of marijuana becoming a legal commercial crop in North America is, to say the least, unlikely in the foreseeable future. Nevertheless the private sector is currently producing medicinal marijuana in Europe and Canada, so the following orientation to marijuana as a potential authorized crop is not merely academic.

                The objectivity of scientific evaluation of the medicinal value of marijuana to date has been questioned. In the words of Hirst et al. (1998): “The ...status of cannabis has made modern clinical research almost impossible. This is primarily because of the legal, ethical and bureaucratic difficulties in conducting trials with patients. Additionally, the general attitude towards cannabis, in which it is seen only as a drug of abuse and addiction, has not helped.” In a recent editorial, the respected journal Nature (2001) stated: “Governments, including the US federal government, have until recently refused to sanction the medical use of marijuana, and have also done what they can to prevent its clinical testing. They have defended their inaction by claiming that either step would signal to the public a softening of the so-called ‘war on drugs.’... The pharmacology of cannabinoids is a valid field of scientific investigation. Pharmacologists have the tools and the methodologies to realize its considerable potential, provided the political climate permits them to do so.” Given these current demands for research on medicinal marijuana, it will be necessary to produce crops of drug types of C. sativa.

                Earliest reference to euphoric use of C. sativa appears to date to China of 5 millennia ago, but it was in India over the last millennium that drug consumption became more firmly entrenched than anywhere else in the world. Not surprisingly, the most highly domesticated drug strains were selected in India. While C. sativa has been used as a euphoriant in India, the Near East, parts of Africa, and other Old World areas for thousands of years, such use simply did not develop in temperate countries where hemp was raised. The use of C. sativa as a recreational inebriant in sophisticated, largely urban settings is substantially a 20^th century phenomenon.

                Cannabis drug preparations have been employed medicinally in folk medicine since antiquity, and were extensively used in western medicine between the middle of the 19^th century and World War II, particularly as a substitute for opiates (Mikuriya 1969; a bottle of commercial medicinal extract is shown in Fig. 41). Medical use declined with the introduction of synthetic analgesics and sedatives, and there is very limited authorized medical use today, but considerable unauthorized use, including so-called “compassion clubs” dispensing marijuana to gravely ill people, which has led to a momentous societal and scientific debate regarding the wisdom of employing cannabis drugs medically, given the illicit status. There is anecdotal evidence that cannabis drugs are useful for: alleviating nausea, vomiting and anorexia following radiation therapy and chemotherapy; as an appetite stimulant for AIDS patients; for relieving the tremors of multiple sclerosis and epilepsy; and for pain relief, glaucoma, asthma, and other ailments (see Mechoulam and Hanus (1997) for an authoritative medical review, and Pate (1995) for a guide to the medical literature). To date, governmental authorities in the US, on the advice of medical experts, have consistently rejected the authorization of medical use of marijuana except in a handful of cases. However, in the UK medicinal marijuana is presently being produced sufficient to supply thousands of patients, and Canada recently authorized the cultivation of medicinal marijuana for compassionate dispensation, as well as for a renewed effort at medical evaluation.

                Several of the cannabinoids are reputed to have medicinal potential: THC for glaucoma, spasticity from spinal injury or multiple sclerosis, pain, inflammation, insomnia, and asthma; CBD for some psychological problems. The Netherlands firm HortaPharm developed strains of Cannabis rich in particular cannabinoids. The British firm G.W. Pharmaceuticals acquired proprietary access to these for medicinal purposes, and is developing medicinal marijuana. In the US, NIH (National Institute of Health) has a program of research into medicinal marijuana, and has supplied a handful of individuals for years with maintenance samples for medical usage. The American Drug Enforcement Administration is hostile to the medicinal use of Cannabis, and for decades research on medicinal properties of Cannabis in the US has been in an extremely inhospitable climate, except for projects and researchers concerned with curbing drug abuse. Synthetic preparations of THC - dronabinol (Marinol®) and nabilone (Cesamet®) - are permitted in some cases, but are expensive and widely considered to be less effective than simply smoking preparations of marijuana. Relatively little material needs to be cultivated for medicinal purposes (Small 1971), although security considerations considerably inflate costs. The potential as a “new crop” for medicinal cannabinoid uses is therefore limited. However, the added-value potential in the form of proprietary drug derivatives and drug-delivery systems is huge. The medicinal efficacy of Cannabis is extremely controversial, and regrettably is often confounded with the issue of balancing harm and liberty concerning the proscriptions against recreational use of marijuana. This paper is principally concerned with the industrial uses of Cannabis. In this context, the chief significance of medicinal Cannabis is that, like the issue of recreational use, it has made it very difficult to rationally consider the development of industrial hemp in North America for purposes that everyone should agree are not harmful.

                Key analyses of the medicinal use of marijuana are: Le Dain (1972), Health Council of the Netherlands (1996), American Medical Association (1997), British Medical Association (1997), National Institutes of Health (1997), World Health Organization (1997), House of Lord (1998), and Joy et al. (1999).

                It has been contended that hemp is notably superior to most crops in terms of biomass production, but van der Werf (1994b) noted that the annual dry mater yield of hemp (rarely approaching 20 tonnes/ha) is not exceptional compared to corn, beets, or potato. Nevertheless, hemp has been rated on a variety of criteria as one of the best crops available to produce energy in Europe (Biewinga and van der Bijl 1996). Hemp, especially the hurds, can be burned as is or processed into charcoal, methanol, methane, or gasoline through pyrolysis (destructive distillation). As with corn, hemp can also be used to create ethanol. However, hemp for such biomass purposes is a doubtful venture in North America. Conversion of hemp biomass into fuel or alcohol is impractical on this continent, where there are abundant supplies of wood, and energy can be produced relatively cheaply from a variety of sources. Mallik et al. (1990) studied the possibility of using hemp for “biogas” (i.e. methane) production, and concluded that it was unsuitable for this purpose. Pinfold Consulting (1998) concluded that while there may be some potential for hemp biomass fuel near areas where hemp is cultivated, “a fuel ethanol industry is not expected to develop based on hemp.”

                Essential (volatile) oil in hemp is quite different from hempseed oil. Examples of commercial essential oil product products are shown in Fig. 42. The essential oil is a mixture of volatile compounds, including monoterpenes, sesquiterpenes, and other terpenoid-like compounds that are manufactured in the same epidermal glands in which the resin of Cannabis is synthesized (Meier and Mediavilla 1998). Yields are very small - about 10 L/ha (Mediavilla and Stenemann 1997), so essential oil of C. sativa is expensive, and today is simply a novelty. Essential oil of different strains varies considerably in odor, and this may have economic importance in imparting a scent to cosmetics, shampoos, soaps, creams, oils, perfumes, and foodstuffs. Switzerland has been a centre for the production of essential oil for the commercial market. Narcotic strains tend to be more attractive in odor than fiber strains, and because they produce much higher numbers of flowers than fiber strains, and the (female) floral parts provide most of the essential oil, narcotic strains are naturally adapted to essential oil production. Switzerland has permitted strains with higher THC content to be grown than is allowed in other parts of the world, giving the country an advantage with respect to the essential oil market. However, essential oil in the marketplace has often been produced from low-THC Cannabis, and the THC content of essential oil obtained by steam distillation can be quite low, producing a product satisfying the needs for very low THC levels in food and other commercial goods. The composition of extracted essential oil is quite different from the volatiles released around the fresh plant (particularly limonene and alpha-pinene), so that a pleasant odor of the living plant is not necessarily indicative of a pleasant-smelling essential oil. Essential oil has been produced in Canada by Gen-X Research Inc., Regina. The world market for hemp essential oil is very limited at present, and probably also has limited growth potential.

                McPartland (1997) reviewed research on the pesticide and repellent applications of Cannabis. Dried plant parts and extracts of Cannabis have received rather extensive usage for these purposes in the past, raising the possibility that research could produce formulations of commercial value. This possibility is currently hypothetical.

                As noted above, hemp seed cake makes an excellent feed for animals. However, feeding entire plants is another matter, because the leaves are covered with the resin-producing glands. While deer, groundhogs, rabbits, and other mammals will nibble on hemp plants, mammals generally do not choose to eat hemp. Jain and Aroroa (1988) fed narcotic Cannabis refuse to cattle, and found that the animals “suffered variable degrees of depression and revealed incoordination in movement.” By contrast, Letniak et al. (2000) conducted an experimental trial of hemp as silage. No significant differences were found between yield of the hemp and of barley/oat silage fed to heifers, suggesting that fermenting hemp plants reduces possible harmful constituents.

                One of the most curious uses of hemp is as a fence to prevent pollen transfer in commercial production of seeds. Isolation distances for ensuring that seeds produced are pure are considerable for many plants, and often impractical. At one point in the 1980s, the only permitted use of hemp in Germany was as a fence or hedge to prevent plots of beets being used for seed production from being contaminated by pollen from ruderal beets. The high and rather inpenetrable hedge that hemp can produce was considered unsurpassed by any other species for the purpose. As well, the sticky leaves of hemp were thought to trap pollen. However, Saeglitz et al. (2000) demonstrated that the spread of beet pollen is not effectively prevented by hemp hedges. Fiber (i.e. tall) varieties of hemp were also once used in Europe as wind-breaks, protecting vulnerable crops against wind damage. Although hemp plants can lodge, on the whole very tall hemp is remarkably resistant against wind.

                Preliminary work in Germany (noted in Karus and Leson 1994) suggested that hemp could be grown on soils contaminated with heavy metals, while the fiber remained virtually free of the metals. Koz»owski et al. (1995) observed that hemp grew very well on copper-contaminated soil in Poland (although seeds absorbed high levels of copper). Baraniecki (1997) found similar results. Mölleken et al. (1997) studied effects of high concentration of salts of copper, chromium and zinc on hemp, and demonstrated that some hemp cultivars have potential application to growth in contaminated soils. It would seem unwise to grow hemp as an oilseed on contaminated soils, but such a habitat might be suitable for a fiber or biomass crop. The possibility of using hemp for bioremediation deserves additional study.

                Hemp is plagued by bird predation, which take a heavy toll on seed production. The seeds are well know to provide extremely nutritious food for both wild birds and domestic fowl. Hunters and birdwatchers who discover wild patches of hemp often keep this information secret, knowing that the area will be a magnet for birds in the fall when seed maturation occurs. Increasingly in North America, plants are being established to provide habitat and food for wildlife. Hemp is not an aggressive weed, and certainly has great potential for being used as a wildlife plant. Of course, current conditions forbid such usage in North America.

                Hemp has at times in the past been grown simply for its ornamental value. The short, strongly-branched cultivar ‘Panorama’ (Fig. 43) bred by Iván Bósca, the dean of the world’s living hemp breeders, was commercialized in Hungary in the 1980s, and has been said to be the only ornamental hemp cultivar available. It has had limited success, of course, because there are very few circumstances that permit private gardeners can grow Cannabis as an ornamental today. By contrast, beautiful ornamental cultivars of opium poppy are widely cultivated in home gardens across North America, despite their absolute illegality and the potentially draconian penalties that could be imposed. Doubtless in the unlikely event that it became possible, many would grow hemp as an ornamental.

                The following sketch of hemp cultivation is insufficient to address all of the practical problems that are encountered by hemp growers. Bócsa and Karus (1998) is the best overall presentation of hemp growing available in English. The reader is warned that this book, as well as almost all of the literature on hemp, is very much more concerned with fiber production than oilseed production. McPartland et al. (2000) is the best presentation available on diseases and pests, which fortunately under most circumstances do limited damage. The resource list presented below should be consulted by those wishing to learn about hemp production. Provincial agronomists in Canada now have experience with hemp, and can make local recommendations. Particularly good web documents are: for Ontario (OMAFRA Hemp Series, several documents): ; for Manitoba (several documents): ; for British Columbia: (BC Ministry of Agriculture and Foods Fact Sheet on Industrial Hemp, prepared by A. Oliver and H. Joynt): http://www.agf.gov.bc.ca/croplive/plant/horticult/specialty/specialty.htm

In the US, extension publications produced up to the end of World War II are still useful, albeit outdated (e.g. Robinson 1935; Wilsie et al. 1942; Hackleman and Domingo 1943; Wilsie et al. 1944).

                Hemp does best on a loose, well-aerated loam soil with high fertility and abundant organic matter. Well-drained clay soils can be used, but poorly-drained clay soils are very inappropriate because of their susceptibility to compaction, which is not tolerated. Young plants are sensitive to wet or flooded soils, so that hemp must have porous, friable, well-drained soils. Sandy soils will grow good hemp, provided that adequate irrigation and fertilization are provided, but doing so generally makes production uneconomical. Seedbed preparation requires considerable effort. Fall plowing is recommended, followed by careful preparation of a seedbed in the spring. The seedbed should be fine, level, and firm. Seed is best planted at 2-3 cm (twice as deep will be tolerated). Although the seedlings will germinate and survive at temperatures just above freezing, soil temperatures of 8-10EC are preferable. Generally hemp should be planted afer danger of hard freezes, and slightly before the planting date of corn. Good soil moisture is necessary for seed germination, and plenty of rainfall is needed for good growth, especially during the first 6 weeks. Seeding rate is specific to each variety, and this information should be sought from the supplier. Fiber strains are typically sown at a minimum rate of 250 seeds per m² (approximately 45 kg/ha), and up to three times this density is sometimes recommended. In western Europe, seeding rates range from 60 to 70 kg/ha for fiber cultivars. Recommendations for seeding rates for grain production vary widely, from 10-45 kg/ha. Densities for seed production for tall, European, dual-purpose cultivars are less than for short oilseed cultivars. Low plant densities, as commonly found in growing tall European cultivars for seed, may not suppress weed growth adequately, and under these circumstances resort to herbicides may pose a problem for those wishing to grow hempseed organically. Hemp requires about the same fertility as a high-yielding crop of wheat. Industrial hemp grows well in areas that corn produces high yields. Growing hemp may require addition of up to 110 kg/ha of nitrogen, and 40-90- kg/ha of potash. Hemp particularly requires good nitrogen fertilization, more so for seed production than fiber. Adding nitrogen when it is not necessary is deleterious to fiber production, so that knowledge of the fertility of soils being used is very important. Organic matter is preferably over 3.5%, phosphorus should be medium to high (>40 ppm), potassium should be medium to high (>250 ppm), sulfur good (>5,000 ppm) and calcium not in excess (<6,000 ppm).

                Finding cultivars suited to local conditions is a key to success. Hemp prefers warm growing conditions, and the best European fiber strains are photoperiodically adapted to flowering in southern Europe, which provides seasons of at least 4 months for fiber, and 5.5 months for seed production. Asian land races are similarly adapted to long seasons. In Canada, many of the available cultivars flower too late in the season for fiber production, and the same may be predicted for the northern US. Fiber production should also be governed by availability of moisture throughout the season, and the need for high humidity in the late summer and fall for retting, so that large areas of the interior and west of North America are not adapted to growing fiber hemp. The US Corn Belt has traditionally been considered to be best for fiber hemp. There are very few cultivars dedicated to oilseed production (such as ‘Finola’ and ‘Anka’) or that at least are known to produce good oilseed crops (such as ‘Fasamo’ and ‘Uniko-B’). Oilseed production was a specialty of the USSR, and there is some likelihood that northern regions of North America may find short-season, short-stature oilseed cultivars ideal.

                Although hemp can be successfully grown continuously for several years on the same land, rotation with other crops is desirable. A 3- or preferably 4-year rotation may involve cereals, clover or alfalfa for green manure, corn, and hemp. In Ontario it has been recommended that hemp not follow canola, edible beans, soybeans or sunflowers. However, according to Bócsa and Karus (1998), “it matters little what crops are grown prior to hemp.”

                For a fiber crop, hemp is cut in the early flowering stage or while pollen is being shed, well before seeds are set. Tall European cultivars (greater than 2 m) plants have mostly been grown in Canada to date, and most of these are photoperiodically adapted to mature late in the season (often too late). Small crops have been harvested with sickle-bar mowers and hay swathers, but plugging of equipment is a constant problem. Hemp fibers tend to wrap around combine belts, bearings, indeed any moving part, and have resulted in large costs of combining repairs (estimated at $10.00/ha). Slower operation of conventional combines has been recommended (0.6 - 2 ha/hour). Large crops may require European specialized equipment, but experience in North America with crops grown mainly for fiber is limited. The Dutch company HempFlax has developed or adapted several kinds of specialized harvesting equipment (Figs. 44, 45).

                Retting is generally done in the field (Figs. 46, 47). This typically requires weeks. The windrows should be turned once or twice. If not turned, the stems close to the ground will remain green while the top ones are retted and turn brown. When the stalks have become sufficiently retted requires experience - the fibers should have turned golden or grayish in color, and should separate easily from the interior wood. Baling can be done with any kind of baler (Fig. 48). Stalks should have less than 15% moisture when baled, and should be allowed to dry to about 10% in storage. Bales must be stored indoors. Retted stalks are loosely held together, and for highest quality fiber applications, need to be decorticated, scutched, hackled and combed to remove the remaining pieces of stalks, broken fibers, and extraneous material. The equipment for this is rare in North America, and consequently use of domestically-produced fiber for high quality textile applications is extremely limited. However, as described above relatively crude fiber preparations also have applications.

                Harvesting tall varieties for grain is difficult. In France, the principal grower of dual-purpose varieties, the grain is taken off the field first, leaving most of the stalks for later harvest (Fig. 49). Putting tall whole plants through a conventional combine results in the straw winding around moving parts, and the fibers working into bearing, causing breakdown, fires, high maintenance, and frustration. Following the French example of raising the cutting blade to harvest the grain is advisable. Growing short varieties dedicated to grain production eliminates many of the above problems, and since the profitability of hemp straw is limited at present, seems preferable. Grain growers should be aware that flocks of voracious birds are a considerable source of damage to hempseed, particularly in small plantations.

                Although the environmental and biodiversity benefits of growing hemp have been greatly exaggerated in the popular press, C. sativa  is nevertheless exceptionally suitable for organic agriculture, and is remarkably less “ecotoxic” in comparison to most other crops (Montford and Small 1999b). Figure 50 presents a comparison of the ecological friendliness of Cannabis crops (fiber, oilseed, and narcotics) and 21 of the world’s major crops, based on 26 criteria used by Montford and Small (1999a) to compare the ecological friendliness of crops.

                The most widespread claim for environmental friendliness of hemp is that it has the potential to save trees that otherwise would be harvested for production of lumber and pulp. Earlier, the limitations of hemp as a pulp substitute were examined. With respect to wood products, several factors appear to favor increased use of wood substitutes, especially agricultural fibers such as hemp. Deforestation, particularly the destruction of old growth forests, and the world’s decreasing supply of wild timber resources are today major ecological concerns. Agroforestry using tree species is one useful response, but nevertheless sacrifices wild lands and biodiversity, and is less preferable than sustainable wildland forestry. The use of agricultural residues (e.g. straw bales in house construction) is an especially environmentally friendly solution to sparing trees, but material limitations restrict use. Another chief advantage of several annual fiber crops over forestry crops is relative productivity, annual fiber crops sometimes producing of the order of four times as much per unit of land. Still another important advantage is the precise control over production quantities and schedule that is possible with annual crops. In many parts of the world, tree crops are simply not a viable alternative. “By the turn of the century 3 billion people may live in areas where wood is cut faster than it grows or where fuelwood is extremely scarce” (World Commission on Environment and Development 1987). “Since mid-century, lumber use has tripled, paper use has increased six-fold, and firewood use has soared as Third World populations have multiplied” (Brown et al. 1998). Insofar as hemp reduces the need to harvest trees for building materials or other products, its use as a wood substitute will tend to contribute to preserving biodiversity. Hemp may also enhance forestry management by responding to short-term fiber demand while trees reach their ideal maturation. In developing countries where fuelwood is becoming increasingly scarce and food security is a concern, the introduction of a dual-purpose crop such as hemp to meet food, shelter and fuel needs may contribute significantly to preserving biodiversity.

                The most valid claims to environmental friendliness of hemp are with respect to agricultural biocides (pesticides, fungicides, herbicides). Cannabis sativa is known to be exceptionally resistant to pests (note Fig. 51), although, the degree of immunity to attacking organisms has been greatly exaggerated, with several insects and fungi specializing on hemp. Despite this, use of pesticides and fungicides on hemp is usually unnecessary, although introduction of hemp to regions should be expected to generate local problems. Cannabis sativa is also relatively resistant to weeds, and so usually requires relatively little herbicide. Fields intended for hemp use are still frequently normally cleared of weeds using herbicides, but so long as hemp is thickly seeded (as is always done when hemp is grown for fiber), the rapidly developing young plants normally shade out competing weeds.

                The basic commercial options for growing hemp in North America is as a fiber plant, an oilseed crop, or for dual harvest for both seeds and fiber. Judged on experience in Canada to date, the industry is inclined to specialize on either fiber or grain, but not both. Hemp in our opinion is particularly suited to be developed as an oilseed crop in North America. The first and foremost breeding goal is to decrease the price of hempseed by creating more productive cultivars. While the breeding of hemp fiber cultivars has proceeded to the point that only slight improvements can be expected in productivity in the future, the genetic potential of hemp as an oilseed has scarcely been addressed. From the point of view of world markets, concentrating on oilseed hemp makes sense, because Europe has shown only limited interest to date in developing oilseed hemp, whereas a tradition of concentrating on profitable oilseed products is already well established in the US and Canada. Further, China’s supremacy in the production of high-quality hemp textiles at low prices will be very difficult to match, while domestic production of oilseeds can be carried out using technology that is already available. The present productivity of oilseed hemp - about 1 tonne/ha under good conditions, and occasional reports of 1.5 to 2 tonnes/ha, is not yet sufficient for the crop to become competitive with North America’s major oilseeds. We suggest that an average productivity of 2 tonnes/ha will be necessary to transform hempseed into a major oilseed, and that this breeding goal is achievable. At present, losses of 30% of the seed yields are not uncommon, so that improvements in harvesting technology should also contribute to higher yields. Hemp food products cannot escape their niche market status until the price of hempseed rivals that of other oilseeds, particularly rapeseed, flax, and sunflower. Most hemp breeding that has been conducted to date has been for fiber characteristics, so that there should be considerable improvement possible. The second breeding goal is for larger seeds, as these are more easily shelled. Third is breeding for specific seed components. Notable are the health-promoting gamma-linolenic acid; improving the amino acid spectrum of the protein; and increasing the antioxidant level, which would not only have health benefits but could increase the shelf life of hemp oil and foods.

                Germplasm for the improvement of hemp is vital for the future of the industry in North America. However, there are no publically available germplasm banks housing C. sativa in North America. The hundreds of seed collections acquired for Small’s studies (reviewed in Small 1979) were destroyed in 1980 because Canadian government policy at that time envisioned no possibility that hemp would ever be developed as a legitimate crop. An inquiry regarding the 56 United States Department of Agriculture hemp germplasm collections supplied to and grown by Small and Beckstead (1973) resulted in the reply that there are no remaining hemp collections in USDA germplasm holdings, and indeed that were such to be found they would have to be destroyed. While hemp has been and still is cultivated in Asia and South America, it is basically in Europe that germplasm banks have made efforts to preserve hemp seeds. The Vavilov Institute of Plant Research in St. Petersburg, Russia has by far the largest germplasm collection of hemp of any public gene bank, with about 500 collections (detailed information on the majority of hemp accessions of the Vavilov Institute can be found in Anonymous (1975)). Budgetary problems in Russia have endangered the survival of this invaluable collection, and every effort needs to be made to find new funding to preserve it. Maintenance and seed generation issues for the Vavilov hemp germplasm collection are discussed in a number of articles in the Journal of the International Hemp Association (e.g.Clarke 1998b; Lemeshev et al.1993, 1994). The Gatersleben gene bank of Germany, the 2^nd largest public gene bank in Europe, has a much smaller Cannabis collection, with less than 40 accessions (detailed information on the hemp accessions of the Gatersleben gene bank are available at ). Because hemp is regaining its ancient status as an important crop, a number of private germplasm collections have been assembled for the breeding of cultivars as commercial ventures (for examples see de Meijer 1999; de Meijer and van Soest 1992), and of course these are available only on a restricted basis, if at all.

                The most pressing need of the hemp industry in North America is for the breeding of more productive oilseed cultivars. At present, mainly European cultivars are available, of which very few are suitable for specialized oilseed production. More importantly, hempseed oil is not competitive, except in the novelty niche market, with the popular food oils. As argued above, to be competitive, hemp should produce approximately 2 tonnes/ha; at present 1 tonne/ha is considered average to good production. Doubling the productive capacity of a conventional crop would normally be considered impossible, but it needs to be understood just how little hemp has been developed as an oilseed. There may not even be extant land races of the kind of hemp oilseed strains that were once grown in Russia, so that except for a very few very recent oilseed cultivars, there has been virtually no breeding of oilseed hemp. Contrarily, hemp has been selected for fiber to the point that some breeders consider its productivity in this respect has already been maximised. Fiber strains have been selected for low seed production, so that most hemp germplasm has certainly not been selected for oilseed characteristics. By contrast, drug varieties have been selected for very high yield of flowers, and accordingly produce very high yield of seeds. Drug varieties have been observed to produce more than a kilogram of seed per plant, so that a target yield of several tonnes per hEctare is conceivable (Watson and Clarke 1997). Of course, the high THC in drug cultivars makes these a difficult source of germplasm. However, wild plants of C. sativa have naturally undergone selection for high seed productivity, and are a particularly important potential source of breeding germplasm.

                Wild North American hemp is derived mostly from escaped European cultivated hemp imported in past centuries, perhaps especially from a revival of cultivation during World War II. Wild Canadian hemp is concentrated along the St. Lawrence and lower Great Lakes, where considerable cultivation occurred in the 1800s. In the US, wild hemp is best established in the American Midwest and Northeast, where hemp was grown historically in large amounts. Decades of eradication have exterminated many of the naturalized populations in North America. In the US, wild plants are rather contemptuously called “ditch weed” by law enforcement personnel. However, the attempts to destroy the wild populations are short-sighted, because they are a natural genetic reservoir, mostly low in THC. Wild North American plants have undergone many generations of natural adaptation to local conditions of climate, soil and pests, and accordingly it is safe to conclude that they harbor genes that are invaluable for the improvement of hemp cultivars. We have encountered exceptionally vigorous wild Canadian plants (Fig. 52), and grown wild plants from Europe (Fig. 46) which could prove valuable. Indeed, studies are in progress in Ontario to evaluate the agronomic usefulness of wild North American hemp. Nevertheless, present policies in North America require the eradication of wild hemp wherever encountered. In Europe and Asia, there is little concern about wild hemp, which remains a valuable resource.

                It is clear that there is a culture of idealistic believers in hemp in North America, and that there is great determination to establish the industry. As history has demonstrated, unbridled enthusiasm for largely untested new crops touted as gold mines sometimes leads to disaster. The attempt to raise silk in the US is probably the most egregious example. In 1826 a Congressional report that recommended the preparation of a practical manual on the industry resulted in a contagious desire to plant mulberries for silk production, with the eventual collapse of the industry, the loss of fortunes, and a legacy of “Mulberry Streets” in the US (Chapter 2, Bailey 1898). In the early 1980s in Minnesota, Jerusalem artichoke was touted as a fuel, a feed, a food, and a sugar crop. Unfortunately there was no market for the new “wonder crop” and hundreds of farmers lost about $20 million (Paarlberg 1990). The level of “hype” associated with industrial hemp is far more than has been observed before for other new crops (Pinfold Consulting 1998). Probably more so than any plant in living memory, hemp attracts people to attempt its cultivation without first acquiring a realistic appreciation of the possible pitfalls. American presidents George Washington and Thomas Jefferson encouraged the cultivation of hemp, but both lost money trying to grow it. Sadly in Canada in 1999 numerous farmers contracted to grow half of Canada’s acreage or hemp for the American-based Consolidated Growers and Processors, and with the collapse of the firm were left holding very large amounts of unmarketable grain and baled hemp straw. This has represented a most untimely setback for a fledgling industry, but at least has had a sobering effect on investing in hemp. In this section we emphasize why producers should exercise caution before getting into hemp.

                In Europe and Asia, hemp farming has been conducted for millennia. Although most countries ceased growing hemp after the second word war, some didn’t, including France, China, Russia, and Hungary, so that essential knowledge of how to grow and process hemp was maintained. When commercial hemp cultivation resumed in Canada in 1997, many farmers undertook to grow the crop without appreciating its suitability for their situation, or for the hazzards of an undeveloped market. Hemp was often grown on farms with marginal incomes in the hopes that it was a saviour from a downward financial spiral. The myth that hemp is a wonder crop that can be grown on any soil led some to cultivate on soils with a history of producing poor crops; of course, a poor crop was the result.

                Market considerations also heavily determine the wisdom of investing in hemp. Growing hemp unfortunately has a magnetic attraction to many, so there is danger of overproduction. A marketing board could be useful to prevent unrestrained competition and price fluctuations, but is difficult to establish when the industry is still very small. As noted above, unwise investment in Canada produced a glut of seeds that resulted in price dumping and unprofitable levels for the majority. Cultural and production costs of hemp have been said to be comparable to those for corn, and while the truth of this remains to be confirmed, the legislative burden that accompanies hemp puts the crop at a unique disadvantage. Among the problems that Canadian farmers have faced are the challenge of government licensing (some delays, and a large learning curve), very expensive and sometime poor seed (farmers are not allowed to generate their own seed), teenagers raiding fields in the mistaken belief that marijuana is being grown, and great difficulties in exportation because of the necessity of convincing authorities that hemp is not a narcotic. Unless the producer participates in sharing of value-added income, large profits are unlikely. The industry widely recognizes that value added to the crop is the chief potential source of profit, as indeed for most other crops.

                Cannabis has long had an image problem, because of the extremely widespread use of “narcotic” cultivars as illegal intoxicants. The US Drug Enforcement Administration has the mandate of eliminating illicit and wild marijuana, which it does very well (Figs. 54-56). Those interested in establishing and developing legitimate industries based on fiber and oilseed applications have had to struggle against considerable opposition from many in the political and law enforcement arenas. The United States National Institute on Drug Abuse (NIDA) information web site on marijuana, which reflects a negative view of cannabis, is at and reflects several basic fears:

a) Growing Cannabis plants makes law enforcement more difficult, because of the need to ensure that all plants cultivated are legitimate.

b) Utilization of legitimate Cannabis products makes it much more difficult to maintain the image of the illegitimate products as dangerous.

c) Many in the movements backing development of hemp are doing so as a subterfuge to promote legalization of recreational use of marijuana.

d) THC (and perhaps other constituents) in Cannabis are so harmful that their presence in any amount in any material (food, medicine or even fiber product) represents a health hazard that is best dealt with by a total proscription.

                Ten years ago hemp cultivation was illegal in Germany, England, Canada, Australia, and other countries. Essential to overcoming governmental reluctance in each country was the presentation of an image that was business-oriented, and conservative. The merits of environmentalism have acquired some political support, but unless there is a reasonable possibility that hemp cultivation is perceived as potentially economically viable, there is limited prospect of having anti-hemp laws changed. Strong support from business and farm groups is indispensable; support from pro-marijuana interests and what are perceived of as fringe groups is generally counterproductive. It is a combination of prospective economic benefit coupled with assurance that hemp cultivation will not detrimentally affect the enforcement of marijuana legislation that has led most industrially advanced countries to reverse prohibitions against growing hemp. Should the US permit commercial hemp cultivation to resume, it will likely be for the same reasons.

                The US Office of National Drug control Policy issued a statement on industrial hemp in 1997 () which included the following: “Our primary concern about the legalization of the cultivation of industrial hemp (Cannabis sativa) is the message it would send to the public at large, especially to our youth at a time when adolescent drug use is rising rapidly... The second major concern is that legalizing hemp production may mean the de facto legalization of marijuana cultivation. Industrial hemp and marijuana are the product of the same plant, Cannabis sativa... Supporters of the hemp legalization effort claim hemp cultivation could be profitable for U.S. farmers. However, according to the USDA and the U.S. Department of Commerce, the profitability of industrial hemp is highly uncertain and probably unlikely. Hemp is a novelty product with limited sustainable development value even in a novelty market... For every proposed use of industrial hemp, there already exists an available product, or raw material, which is cheaper to manufacture and provides better market results.... Countries with low labor costs such as the Philippines and China have a competitive advantage over any U.S. hemp producer.”

                Recent European Commission proposals to change its subsidy regime for hemp contained the following negative evaluation of hemp seed: “The use of hemp seed...would, however, even in the absence of THC, contribute towards making the narcotic use of cannabis acceptable... In this light, subsidy will be denied producers who are growing grain for use in human nutrition and cosmetics.”

                A USDA analysis of hemp, “Industrial hemp in the United States: status and market potential,” was issued in 2000, and is available at This is anonymously-authored, therefore presumably represents a corporate or “official” evaluation. The conclusion was that “U.S. markets for hemp fiber (specialty textiles, paper, and composites) and seed (in food or crushed for oil) are, and will likely remain, small, thin markets. Uncertainty about longrun demand for hemp products and the potential for oversupply discounts the prospects for hemp as an economically viable alternative crop for American farmers.” Noting the oversupply of hempseeds associated with Canada’s 30,000 acres in 1999, the report concluded that the long term demand for hemp products is uncertain, and predicts that the hemp market in the US will likely remain small and limited. With respect to textiles, the report noted the lack of a thriving textile flax (linen) US industry (despite lack of legal barriers), so that it would seem unlikely that hemp could achieve a better market status. With respect to hemp oil, the report noted that hemp oil in food markets is limited by its short shelf life, the fact that it can not be used for frying, and the lack of US Food and Drug Administration approval as GRAS (“generally recognized as safe”). Moreover, summarizing four state analyses of hemp production (McNulty 1995, Ehrensing 1998, Kraenzel et al. 1998, Thompson et al. 1998), profitability seemed doubtful.

                Without arguing the merits of the above contentions, we point out that the legitimate use of hemp for non-intoxicant purposes has been inhibited by the continuing ferocious war against drug abuse. In this atmosphere, objective analysis has often been lacking. Unfortunately both proponents and opponents have tended to engage in exaggeration. Increasingly, however, the world is testing the potential of hemp in the field and marketplace, which surely must be the ultimate arbiters. De Guzman (2001), noting the pessimistic USDA report, observed that “Nevertheless, others point to the potential of [the] market. Hemp products have a growing niche market of their own, and the market will remain healthy and be well supported with many competing brands.”

                A wide variety of hemp clothing, footwear, and food products are now available in North America. Some American manufacturers and distributors have chosen to exploit the association of hemp products with marijuana in their advertising. Such marketing is unfortunate, sending the message that some in the industry are indifferent to the negative image that this generates in the minds of much of the potential consuming public. Admittedly, such advertising works. But marketing based on the healthful and tasteful properties of hemp food products, the durable nature of hemp textiles, and the environmental advantages of the crop has proven to be widely acceptable, and is likely to promote the long term development of hemp industries.

                Will hemp commercial cultivation resume in the US in the foreseeable future? This is difficult to judge, but the following considerations suggest this might occur:

a) Increasing awareness of the differences between industrial hemp and marijuana

b) Growing appreciation of the environmental benefits of hemp cultivation

c) Continuing demonstration of successful hemp cultivation and development in most of the remaining western world; all the G8 countries, except the US, produce and export industrial hemp

d) Increasing pressure on state and federal governments to permit hemp cultivation by farmers, particularly wheat, corn, and tobacco farmers in desperate need of substitute crops, but also for rotation crops to break pest and disease cycles

                More than a century ago, an expert on hemp concluded his manual on hemp-growing in the US by stating “There is no question that when the inventive genius, comprehension and energies of the American people become interested, another grand source of profitable employment and prosperity will be established” (Boyce 1900).

                Individual entrepreneurs, and indeed whole industries, as a matter of economic survival need to adopt a clear investment policy with respect to whether their market is to be output-driven or demand-led. From the individual producer’s perspective, the old adage “find your market before you plant your seed” remains sound advice.

                In the mid 1990s, the EU provided subsidization for hemp cultivation of ca. $1,050.00/ha. This support was instrumental in developing a hemp industry in western Europe. However, no comparable support is available in North America, and indeed those contemplating entering into hemp cultivation are faced with extraordinary costs and/or requirements in connection with licensing, security, THC analysis, and record keeping. Those involved in value-added processing and distribution are also faced with legal uncertainties and the regular threat of idiosyncratic, indeed irrational actions of various governments. Simply displaying a C. sativa leaf on advertising has led to the threat of criminal charges in the last decade in several G8 countries. Attempting to export or import hemp products among countries is presently a most uncertain activity.

                It often takes 10 to 15 years for the industry associated with a new agricultural crop to mature. While it is true that foreign imports have been the basis for hemp products in North America for at least a decade, North American production is only 4 years of age in Canada, and farming of hemp in the US has not even begun. Viewed from this perspective, the hemp industry in North America is still very much in its infancy. Varieties of hemp specifically suited to given products and regions have only started to be developed in North America. There is considerable uncertainty regarding yields, costs of production, harvesting and processing equipment, product characteristics, foreign competition, governmental support, and the vagaries of the regulatory environment. Hemp is not presently a standard crop, and is likely to continue experiencing the risks inherent in a small niche market for some time. Hemp is currently a most uncertain crop, but has such a diversity of possible uses, is being promoted by extremely enthusiastic market developers, and attracts so much attention that it is likely to carve out a much larger share of the North American marketplace than its detractors are willing to concede.

                Given the uncertainties and handicaps associated with hemp, it is fortunate that there are compensating factors. As noted, as a crop hemp offers some real environmental advantages, particularly with regard to the limited needs for herbicides and pesticides. Hemp is therefore pre-adapted to organic agriculture, and accordingly to the growing market for products associated with environmentally-friendly, sustainable production. Hemp products are an advertiser’s dream, lending themselves to hyperbole (“healthiest salad oil in the world,” “toughest jeans on the market”). While the narcotics image of C. sativa is often disadvantageous, advertisers who choose to play up this association do so knowing that it will attract a segment of the consuming population. In general, the novelty of hemp means that many consumers are willing to pay a premium price. It might also be said that those who have entered the hemp industry have tended to be very highly motivated, resourceful, and industrious, qualities that have been needed in the face of rather formidable obstacles to progress.

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Table 1. Hemp fiber usage in the European Union in 1999 (after Karus et al. 2000).

Table 2. Analysis of commercial Cannabis product potential in North America.

Decreasing value  |

„

Table 3. Comparative annual world economic significance of categories of Cannabis activity.

___________________________________________________________________________

Category                                World  ($)                              North America ($)              Type of investment

___________________________________________________________________________

Recreational drugs               > 1 trillion                              100's of billions     Law enforcement, eradication, education

Industrial hemp    100's of millions¹                   10's of millions      Production, development, marketing, research

Therapeutic drugs               100's of millions                    10's of millions      Production, development, marketing, research

Phytoremediation 10's of thousands nil                                            Research

Ornamental hemp thousands                             nil                                            Development

___________________________________________________________________________

¹ “The global market for hemp-derived products is valued at between $100 million and $200 million annually” (Pinfold Consulting 1998; De Guzman 2001).

Captions to figures

Fig. 1. Major uses of industrial hemp.

Fig. 2. Cannabis sativa. This superb composite plate by artist Elmer Smith, often reproduced at a very small scale and without explanation in marijuana books, is the best scientific illustration of the hemp plant ever prepared. 1. Flowering branch of male plant. 2. Flowering branch of female plant. 3. Seedling. 4. Leaflet. 5. Cluster of male flowers. 6. Female flower, enclosed by perigonal bract. 7. Mature fruit enclosed in perigonal bract. 8. Seed (achene), showing wide face. 9. Seed, showing narrow face. 10. Stalked secretory gland. 11. Top of sessile secretory gland. 12. Long section of cystolith hair (note calcium carbonate concretion at base). Reproduced with the permission of Harvard University, Cambridge, MA.

Fig. 3. Photograph of Cannabis sativa. Left, staminate (“male”) plant in flower; right, pistillate (“female”) plant in flower.

Fig. 4. United States National Institute of Health, University of Mississippi marijuana plantation site, showing variation in plant size. A tall fiber-type of hemp plant is shown at left, and a short narcotic variety (identified as “Panama Gold”) at right.

Fig. 5. Typical architecture of categories of cultivated Cannabis sativa. Top left: narcotic plants are generally low, highly branched, and grown well-spaced. Top right: plants grown for oilseed were traditionally well-spaced, and the plants developed medium height and strong branching. Bottom left: fiber cultivars are grown at high density, and are unbranched and very tall. Bottom centre: “dual purpose” plants are grown at moderate density, tend to be slightly branched and of medium to tall height. Bottom right: some recent oilseed cultivars are grown at moderate density and are short and relatively unbranched. Degree of branching and height are determined both by the density of the plants and their genetic background.

Fig. 6. ‘Finola,’ the first cultivar of Cannabis sativa bred exclusively for grain. (Courtesy of the breeder, J.C. Callaway, University of Kuopio, Finland.)

Fig. 7. ‘Anka,’ the first registered North American bred cultivar of Cannabis sativa. This variety is best suited for grain production. (Courtesy of the breeder, P. Dragla, and of the Industrial Hemp Seed Development Company, Chatham, Ontario.)

Fig. 8. Scanning electron micrographs of the abaxial surface of a perigonal bract (which envelops the fruit). These bracts are the most intoxicating part of the plant, and may contain 20% THC, dry weight. The resin is synthesized both in stalked and sessile glands. Multicellular secretory glands (of phallic appearance), some broken stalks of these (note cellular appearance), and unicellular cystolith hairs (claw-like structures) are pictured.

Fig. 9. Some important cannabinoids of cannabis resin. )⁹-THC (delta-9 tetrahydrocannabinol) is the chief intoxicant chemical and predominates in intoxicant strains, while the isomer )⁸-THC is usually present in no more than trace amounts. CBD (cannabidiol) is the chief non-intoxicant chemical, and predominates in non-intoxicant strains; it has sedative effects. The non-intoxicant CBN (cannabinol) is a frequent degradation or oxidation product. The non-intoxicaant cannabichromene (CBC) is typically found in trace amounts in intoxicant strains. The non-intoxicant cannabigerol (CBG) is considered to be a precursor of the other cannbinoids (see Fig. 10).

Fig. 10. Proposed biosynthetic pathways of the principal cannabinoids (after Pate 1998b).

Fig. 11. Frequency histograms of THC concentration in germplasm collections. Left, collection of E. Small and D. Marcus; of the 167 accessions, 43% had THC levels >0.3%. Right, the collection of the Vavilov Institute, St. Petersburg; of the 278 accessions for which chemical analyses were reported in Anonymous (1975), about 55% had THC levels >0.3%.

Fig. 12. Cross sections of stems at internodes of a fiber plant (left) and of a narcotic plant (right). Fiber cultivars have stems that are more hollow at the internodes, i.e. less wood, since this allows more energy to be directed into the production of bark fiber.

Fig. 13. Water retting of hemp in Yugoslavia. (Courtesy of Dr. J. Berenji, Institute of Field and Vegetable Crops, Novi Sad.)

Fig. 14. Fiber in retted hemp stem. This stem was bent sharply after retting, breaking the woody central portion (hurds), leaving the bark fibers unbroken. The two portions of stem are separated in this photograph, and are joined by the tough bark fibers.

Fig. 15. Multi-purpose matting, fabricated from hemp. (Courtesy of Kenex Ltd., Pain Court, Ontario.)

Fig. 16. Hemp cigarette paper, the most profitable paper product currently manufactured from hemp.

Fig. 17. Hemp paper products (writing paper, notebook, envelopes).

Fig. 18. C-class Mercedes-Benz automobiles have more than 30 parts made of natural fibers, including hemp. (Courtesy of T. Schloesser, Daimler-Chrysler.)

Fig. 19. Henry Ford swinging an axe at his 1941 car to demonstrate the toughness of the plastic trunk door made of soybean and hemp. (From the collections of Henry Ford Museum & Greenfield Village.)

Fig. 20. Spun, loosely compacted hemp insulation. (Manufactured by La Chanvrière de l’Aube, France.)

Fig. 21. Loose Isochanvre® thermal insulation being placed between joists. (Courtesy of M. Périer, Chènovotte Habitat, France.)

Fig. 22. Experimental fiberboard made with hemp. (Courtesy of Dr. K. Domier, University of Alberta, Edmonton.)

Fig. 23. Molded fiberboard products. (Courtesy of HempFlax, Oude Pekela, The Netherlands).

Fig. 24. New building in France being constructed entirely of hemp. Wall castings are a conglomerate of Isochanvre® lime-hemp, for production of a 200 mm thick monolithic wall

without an interior wall lining. (Courtesy of M. Périer, Chènovotte Habitat, France.)

Fig. 25. The “hemp house” under construction on the Oglala Lakota Nation (Pine Ridge Reservation), South Dakota. Foundation blocks for the house are made with hemp fiber as a binder in cement. Stucco is also of hemp. Shingles are 60% hemp in a synthetic polymer. Hemp insulation is used throughout. (Courtesy of Oglala Sioux Tribe, Slim Butte Land Use Association, and S. Sauser.)

Fig. 26.  Renovation of plaster walls of a traditional timber frame 16^th century house (Mansion Raoul de la Faye, Paris) with Isochanvre® lime-hemp conglomerate. (Courtesy of M. Périer, Chènovotte Habitat, France.)

Fig. 27. Hemp “ceramic tile.” (Courtesy of Kenex Ltd., Pain Court, Ontario.)

Fig. 28. Commercial warehouse of baled hemp animal bedding. (Courtesy of Kenex Ltd., Pain Court, Ontario.)

Fig. 29. Animal bedding made from hemp hurds.

Fig. 30. Pelleted hemp hurds. (Courtesy of La Chanvrière de l’Aube, Bar sur Aube, France.)

Fig. 31. Songbirds on hemp litter. (Courtesy of La Chanvrière de l’Aube, Bar sur Aube, France.)

Fig. 32. Hemp-based erosion control blanket. Top left: Close-up of 100% hemp fiber blanket. Top right: Grass growing through blanket. Bottom: Demonstration of installation of blanket, near La Rivière, Manitoba. (Courtesy of Mark Myrowich, ErosionControlBlanket.com)

Fig. 33. “Seeds” (achenes) of hemp, with a match for scale.

Fig. 34. Some North American food products made with hemp seed and/or hemp seed oil.

Fig. 35. Canned hulled hemp seed. (Courtesy of Kenex Ltd., Pain Court, Ontario.)

Fig. 36. Hemp oil. (Courtesy of La Chanvrière de l’Aube, Bar sur Aube, France.)

Fig. 37. Content of principal fatty acids in hempseed oil, based on means of 62 accessions grown in southern Ontario (reported in Small and Marcus 2000).

Fig. 38. Hemp oil in capsule form sold as a dietary supplement.

Fig. 39. Body care products offered by the Body Shop. (“Chanvre” is French for hemp.)

Fig. 40. A truckload of Canadian medicinal marijuana from a plantation in Ottawa in 1971. More than a ton of marijuana was prepared for experimental research (described in Small et al. 1975).

Fig. 41. Medicinal tincture of Cannabis sativa. (Not legal in North America.)

Fig. 42. Bottles of hemp fragrance (left) and essential oil (centre), and pastilles flavored with hemp essential oil (right).

Fig. 43. ‘Panorama,’ the world’s only ornamental cultivar, with the breeder, Ivan Bócsa. (Courtesy of Professor Bócsa.)

Fig. 44. A John Deere Kemper harvester, with circular drums that cut and chop hemp stalks, shown in operation in southern Ontario. (Courtesy of  Kenex Ltd., Pain Court, Ontario.)

Fig. 45. A hemp harvester operated by HempFlax (Netherlands), with a wide mowing head capable of cutting 3 m long stems into 0.6 m pieces, at a capacity of 3 ha/hour. (Courtesy of HempFlax, Oude Pekela, The Netherlands.)

Fig. 46. Windrowed fiber hemp in process of dew retting. Photograph taken in 1930 on the Central Experimental Farm, Ottawa, Canada.

Fig. 47. Shocked fiber hemp in process of dew retting. Photograph taken in 1931, near Ottawa, Canada. The shocks shed water like pup-tents, providing more even retting than windrows.

Fig. 48. Baled, retted hemp straw. (Courtesy of Kenex Ltd., Pain Court, Ontario.)

Fig. 49. Harvesting hemp in France. (Courtesy of La Chanvrière de l’Aube, Bar sur Aube, France.)

Fig. 50. A crude comparison of the biodiversity friendliness of selected major crops and three Cannabis sativa crops (fiber, oilseed, drug) based on 26 criteria (after Montford and Small 1999a).

Fig. 51. Grasshopper on hemp. Most insects cause only limited damage to hemp, and substantial insect damage is uncommon, so the use of insecticides is very rarely required.

Fig. 52. Wild female hemp plant collected Oct. 17, 2000 near Ottawa, Canada. This vigorous plant had a fresh weight of 1.5 kg.

Fig. 53. A wild female hemp plant grown in southern Ontario (accession #16 from Georgia (formerly USSR), reported in Small and Marcus (2000)). Such highly-branched plants can produce very large quantities of seeds, and may be useful for breeding.

Fig. 54. The war on drugs: helicopter spraying of Paraquat herbicide on field of marijuana. (Courtesy US Drug Enforcement Administration.)

Fig. 55. The war on drugs: clandestine indoor marijuana cultivation. (Courtesy US Drug Enforcement Administration.)

Fig. 56. The war on drugs: burning seized marijuana. (Courtesy US Drug Enforcement Administration.)