Wisconsin Industrial Hemp Production: A basic FAQ guide for growing an old crop in a new era
Wisconsin growers will be able to grow and process industrial hemp under 2017 Wisconsin Act 100, a law recently passed by the Legislature and signed by the Governor. The law directs the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) to write an emergency administrative rule that will spell out the details of the program, including requirements for growers.
This document will be updated as new information becomes available. The emergency rule will remain in effect until July 2020 or until a permanent administrative rule is approved. Please consult the official DATCP and State of Wisconsin websites for official information.
Questions that likely will be addressed by the emergency rule are noted here.
Only official rules, regulations, and notices as posted by the DATCP and State of Wisconsin can be used. Official information from the DATCP and the State of Wisconsin supersedes any information contained here.
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Please click for more information on the Industrial Hemp Research Pilot Program
It is unclear whether there will be a legal mechanism to get hemp seed into Wisconsin in time to plant the 2018 growing season. The Drug Enforcement Administration (DEA) will likely require a DEA Import license for any seed coming from outside Wisconsin. Anyone planting before a license is issued is most likely taking a significant risk.
What is industrial hemp?
As defined in s.94.55 (1) Wis. Stats. “industrial hemp” means the plant Cannabis sativa L., or any part of the plant including seeds, having a Delta-9-Tetrahydrocannabinol (THC) concentration of 0.3% or less, although this allowable percentage may be raised up to a maximum concentration of 1% THC if in the future federal law allows a higher percentage. The statute includes the definition a substance, material, or product that is not designated as a controlled substance under the state Uniform Controlled Substances Act, or the federal Controlled Substances Act, or both.
Industrial hemp is classified as non-drug Cannabis sativa varieties, whose fruit is technically an achene, or a single-seeded fruit similar to a sunflower. Both the seed and hemp’s tall stalk provide significant carbohydrate feedstocks for a wide variety of industrial purposes that are used in several countries. The oil pressed from hempseed in particular, is a rich source of polyunsaturated omega-3 and omega-6 fatty acids, which are essential for human health. These same fatty acids in hempseed oil make it a fine drying oil that is used in the production of paints, varnishes, and other coating materials. Plastic flooring such as linoleum and similar materials have been made from hempseed oil, and other non-food uses of hempseed oil are similar to those of linseed oil (flaxseed oil).
The State of Wisconsin Industrial Hemp Program
Wisconsin Department of Agriculture Trade & Consumer Protection (DATCP) will promulgate rules establishing an industrial hemp program. The State of WI industrial hemp program must generally maximize opportunity for a person to plant, grow, cultivate, harvest, sample, test, process, transport, transfer, take possession of, sell, import, and export industrial hemp to the greatest extent authorized under federal law.
The authorizing legislation requires DATCP to do the following:
- Ensure the quality of industrial hemp grown or processed in this state, the security of activities related to industrial hemp, and the safety of products produced from industrial hemp, including any necessary testing.
- Verify adherence to laws and rules governing activities related to industrial hemp.
- Enforce violations of laws and rules.
- Require an initial fee from any person who plants, grows, or cultivates industrial hemp equal to the greater of $150 or $5 multiplied by the number of acres used to plant, grow, or cultivate industrial hemp, but not to exceed $1,000. An annual fee may also be imposed on any person whose industrial hemp activities are regulated by DATCP. This annual fee may not exceed an amount sufficient to cover DATCP costs to regulate those activities.
- Ensure that certain information in its possession is confidential, except that this information must be made available to a law enforcement agency or law enforcement officer.
DATCP is required to create a pilot program to study the growth, cultivation, and marketing of industrial hemp. The Act requires DATCP to issue licenses that authorize the planting, growing, cultivating, harvesting, sampling, testing, processing, transporting, transferring, taking possession, selling, importing, and exporting of industrial hemp. Such licenses do not expire unless the pilot program expires or the license is revoked.
Further questions that may be addressed by the new rule are:
- How do I apply to grow hemp?
- How long is my pilot production license good for?
- Am I required to do anything else if I participate in the pilot program?
- How do you know my field’s THC content?
- What if my plants test above the acceptable 0.3% delta-9 threshold?
- How does growing hemp affect my FSA and/or federal crop insurance contracts or program participation?
- Can I grow hemp inside a greenhouse?
- Can I see a list of hemp growers or hemp processors licensed in the state?
- Do I need to notify the sheriff/local police?
- Do I need to build a fence or put up signs around my field?
- Can I grow hemp near a school, a town, or a major road? Are there restrictions on where I can grow it?
- Do I need a license to process hemp?
Besides work done in the early 20th century, there is little information on growing hemp in Wisconsin that is based on local research. The following information is gleaned from these references:
When do you plant hemp?
Based on work done in neighboring states, planting done from mid-May to late-June resulted in highest yields with lower risk of frost injury.
What is the seeding rate?
General seeding recommendations is between 20-40 lbs per acre for grain production, and 40-60 lbs per acre for fiber production. A lot of factors go into determining the optimal seeding rate for your field, including the variety, seed purity and germ, local conditions, etc.
The end use of your hemp crop will dictate the seeding rate. When growing hemp for fiber only production, it is suggested the seeding rate should be double what is used for grain production. The reason for higher seeding rates is to ensure a higher quality fiber crop. Good quality hemp fiber comes from plants that are “pencil thin”. Higher seeding rates will ensure that there will be a high plant population with tall thin plants with longer internodes. Research is limited in Canada to determine proper seeding rates to achieve high yielding and good quality fiber. Low plant populations will not provide competition for early weed control. Hemp can have a high mortality rate under adverse growing conditions. Research has shown that 10% to 70% seed mortality can occur under varied climatic conditions. Based on observations, reasons for high mortality are generally attributed to:
- Poor growing conditions at seeding
- Seeding too deep
- Cracking of the seed coat
- Toxicity from high rates of seed placed fertilizer
- Residual herbicides from previous crop
What are some seeding recommendations?
Most conventional drills and seeders will work for hemp. To enhance hemp plant stands:
- Seed into warm soil
- Seed into a firm seedbed with good soil to seed contact
- Seed shallow, 1.25 cm (0.5 inches) to on 2.5 cm (1 inch) maximum
- Do not seed deep into moisture in a dry year. In spite of being a moderately large seed, hemp will struggle to emerge from deep seeding
- Avoid seeding before an abundance of precipitation is anticipated. Seed after a heavy rain rather than before
- Although most seeding equipment will work for hemp it is important to monitor seeder output to avoid seed cracking. Cracking occurs in the manifolds when air volume is too high
- Take into account germination rate. A common percentage of 70% germination is often used when calculating seeding rates. If spring seeding conditions are ideal this rate can be lowered
- Avoid compaction from wheel tracks or other soil compaction, as with other crops, will show up under certain conditions
- Avoid excessive trash that can keep soils cool and could cause hair pinning with disc drills
Can you plant hemp on hemp? How does it fit into a crop rotation?
According to the Canadian Hemp Trade Alliance (CHTA) “hemp fits in with typical crop rotation systems and with typical equipment that would already be found in a grain production system.”
Can I grow hemp organically?
Yes. On August 23, 2016, the National Organic Program (NOP) released this statement: “For hemp produced in the United States, only industrial hemp, produced in accordance with the 2014 Farm Bill, as articulated in the Statement of Principles on Industrial Hemp issued on August 12, 2016 by USDA, may be certified as organic, if produced in accordance with USDA organic regulations.” Some certification agencies will allow industrial hemp to be included in an organic rotation, so long as the growers are properly licensed under a pilot program. However, some certifiers may be taking a more hesitant approach, since there are many questions yet to be answered. Thus, farmers should talk to their certifier before making the decision to include this crop within their organic rotation. If growing industrial hemp, organic farmers will be required to do an organic seed search before using nonorganic seed.
Use practical organic farming practices such as a perennial clover or green manure plow down, with added manure to increase nutrient availability for rapid initial growth. Reduce any weed pressure by plowing and harrowing prior to sowing. The seedbed must be as fine and even as possible. Good soil, farming experience and proper nutrient levels are essential for successful organic oilseed hemp production.
Do you need to fertilize hemp?
Hemp has similar nutrient needs as canola and especially requires added nitrogen. Fertilize like rapeseed (Canola- Brassica napus) with 15% additional nitrogen. Conventional NPKS (nitrogen, phosphorus, potassium and sulfur) fertilization is recommended at the same levels required to grow rapeseed. Apply additional K and S wherever soils are deficient in these elements.
How/When do you harvest it?
Hemp can be grown for seed or fiber. Hemp grain harvesting is generally done by straight combining, however swathing is also used. Newer models of combines are best suited to handling hemp harvest and require minimal modifications. The new machines have bigger cylinders and cleaning area. In addition, newer combines can operate with headers at higher levels so all stands of hemp can be accommodated. Most new combines are now rotary design. Some new machines have the swath entering at the bottom of the cylinder. The draper header is preferred by growers.
The top third of the crop may be combined for grain while the plants are still “green” (70-90% seed head maturity). Harvesting while the crop is partially green will help minimize cutting and wrapping problems. The main disadvantage at harvest is plugging the combine with stems and other moist vegetative material. Dry field conditions are essential for a good harvest. However, a dead and desiccated crop will be more difficult to cut, more prone to wrapping and subsequent fire hazard. Grain moisture should be at least 10-15% at the time of harvest.
What kind of yield can I expect?
Yields can vary widely depending on the variety, local climatic conditions, cultivation method, and grower experience. For grain, new growers have reported yields between 250-700 lbs/acre. More experienced growers can expect between 800- 1,800+ lbs/acre. For fiber, the average yield for dual purpose crops (those varieties which are harvested for grain and fiber) is 0.75-2 tons/acre. For hemp produced solely for fiber, the average yield is between 3-5 tons per acre.
How deep are the roots?
Hemp has a large root capable of penetrating deep in the soil profile to recover nutrients that may be lost to many other crops, up to the 24-inch level.
What are some weed management strategies?
Given a good start, hemp can be an effective weed suppressant. Currently, there are no registered herbicides for weed control in hemp. A quick, even emergence is the key to effectively compete with weeds, by rapidly creating a dense leaf canopy within the first month of growth. Hemp will self thin to an optimal density, and it is better to have this crop compete with itself, rather than weeds. It is recommended to minimize weed pressure in the previous year and start with spring tilling and harrowing. Perennial forages or green manure plow downs are good preceding crops. Problem weeds may include wild buckwheat, wild oat, Amaranthus species, Chenopodium species, rapeseed, and other volunteer crops.
Where can I buy hemp seed from?
The Act requires DATCP to establish and administer an industrial hemp seed certification program, or designate a member of the Association of Official Seed Certifying Agencies or a successor organization to administer a seed certification program. This seed certification
program must include the testing and certification of THC concentrations in hemp plants. Participation in the certification program must be voluntary for growers and cultivators of industrial hemp. The Act also authorizes DATCP to seek federal approval to serve as an importer of industrial hemp seed. Importing seeds into Wisconsin to begin the hemp program may require permission from the U.S. DEA, which could affect the time when production can begin.
Other seed-related questions that may be addressed by the rules are:
- Can I save seed for planting the following year?
- Do I need a seed permit to sell hemp seed in Wisconsin?
- Can I breed a new variety of hemp for Wisconsin?
Do I need a grain buyer’s license to buy hemp grain?
Yes, if you are buying hemp grain with the purpose of reselling the grain or products made from the grain. In addition to a license, a bond must be acquired.
- Hemp is sold as a raw food so avoiding contamination is extremely important.
- All harvest related equipment should be cleaned out prior to harvest to ensure no contamination occurs from other crop types that are difficult to clean out of hemp.
- Combine divergent crops like canola or soybeans before combining hemp. This cleans out the combine and these crops are easily removed if contamination occurs.
- Clean grain as soon as possible to maintain grain quality and ensure safe storage. Inspect trucks for cleanliness before loading clean grain that is destined for the processor.
- For maximum shelf life, grain should be stored in a clean, dry location. Storage temperatures in excess of 75° Fahrenheit for a sustained period of time may cause rancidity and separation of the soluble and insoluble proteins.
- Hemp is combined at a moisture content of 10 to 20% moisture. The majority of the moisture comes from broken plant material, immature seeds and seeds enclosed in bracts. Dockage will range from 10 to 20%. The wetter the sample, the more urgent the drying process is. Drying should begin within hours of harvest. Heated air grain dryers and aeration can be used for drying the seed down
- The industry has accepted 10% moisture as dry. A safer level is 8 or 9%. Percent moisture requirement should be checked with contractor.
- Hemp grain generally has a lot of bracts and broken plant parts that are higher in moisture than the grain. Once drying begins these plant parts dry quickly and the speed at which the grain dries also increases at the end of the drying cycle.
- Monitor grain dryer temperatures to ensure the seed and seed oil quality is not compromised. Overheating the seed can cause the seed to turn yellow and discount the oil quality.
- Use grain drying when seed moisture is over 13 or 14%
- Monitor the dryer operation closely. Batch and continuous flow dryers are the most commonly used. Augers should be run full and slow to prevent cracking of the grain.
- Use heat of 150 to 160 degrees F for the first ½ of the drying period and then use 120 to 130 degrees to finish off the drying.
- Cleaning is required to remove contaminants such as weed seeds, plant parts and insects and it should be conducted as soon as possible after harvest. More importantly, cleaning removes cracked seeds resulting from combining.
- When cracked seeds are exposed to the air it causes oxidized rancidity of the oil which will contaminate the other seeds in the seed lot. This gives the hemp seed an undesirable taste and shortens the shelf life.
Economics and Marketing
Further marketing information can be found at:
Alberta Agriculture and Forestry
Who will buy my hemp if I grow it?
The market is limited and constantly in flux for hemp in the U.S. due to many different factors. We encourage interested individuals to contact a hemp trade association to learn more about marketing opportunities.
How much can I sell my hemp for?
Prices for hemp grain are widely fluctuating in the U.S. specifically due to the infancy and constant development of the industry. According to the Alberta Agriculture and Forestry Department, the average hemp grain price in 2015 in Alberta was $0.74 per pound. Typical returns for hemp grain in the U.S. have been between $0.40-0.70 per pound for conventional, and $0.75-1.00 per pound for organic. Due to the volatile nature of the current U.S. hemp industry, growers are advised to secure a contract before they plant.
What is the cost per acre?
The Alberta Agriculture and Forestry Department reported an average total production cost for hemp seed grown on dryland in 2015 at $409 per acre. With an average grain yield of 1,074 pounds per acre, that amounted to $0.38 per pound of hemp seed produced.
In Minnesota, hemp seed prices are widely variable based on the variety and the source. Imported seed has additional shipping and customs fees above and beyond domestically produced seed. Farmers should also consider the possibility of needing to buy or rent new harvesting equipment if they grow hemp. In 2016, hemp producers in Minnesota reported costs per acre between $970-$2,500 per acre. In 2017, initial reports indicate production costs of between $300-$600 per acre (does not include land cost).
Other questions that may be addressed by the new rules:
- Who will process my hemp in WI?
- Where are processors located in WI?
- Can I export hemp product to other countries?
- Can I sell grain or fiber to other states?
- Can I sell seed to other states?
- Are there any grants that I can get?
- Can I grow hemp under contract with someone else?
Can I feed hemp to my livestock?
Hemp is not currently an approved ingredient for commercial animal feed. Therefore, hemp material cannot be sold as animal feed.
Other sources of information
Wisconsin Hemp 101: Educational Seminar
Date: Jan 30, 2018 6:30PM
Venue: Chippewa Valley Technical College – Eau Claire
Defining Hemp: A Fact Sheet
Botanically, hemp and marijuana are from the same species of plant, Cannabis sativa. However, hemp and marijuana are genetically distinct forms of cannabis that are distinguished by their use and chemical composition as well as by differing cultivation practices in their production. The two are from distinct strains of Cannabis sativa called varieties or cultivars.
While marijuana generally refers to the psychotropic drug (whether used for medicinal or recreational purposes), hemp is cultivated for use in the production of a wide range of products, including foods and beverages, personal care products, nutritional supplements, fabrics and textiles, paper, construction materials, and other manufactured and industrial goods.
Hemp is generally characterized by plants that are low in delta-9 THC, the dominant psychotrophic compound in Cannabis sativa. In addition to its low THC content, hemp generally has high levels of cannabidiol (CBD), the primary nonpsychotropic compound in Cannabis sativa. Hemp and marijuana have varying statutory definitions in U.S. law. Changes enacted as part of the 2018 farm bill (Agriculture Improvement Act of 2018, P.L. 115-334) distinguish between hemp and marijuana in terms of policy and federal regulatory oversight. The 2018 farm bill amended the Controlled Substances Act (21 U.S.C. §§801 et seq.) to specify that the term marijuana excludes hemp (as defined in the 2018 farm bill), thereby permitting the production and sale of hemp and hemp-derived products.
Since the late 1950s, hemp’s association with marijuana had placed it under control and regulation of the U.S. Drug Enforcement Administration (DEA). The 2018 farm bill instead established a new regulatory framework to monitor compliance and regulate hemp production under the jurisdiction of the U.S. Department of Agriculture (USDA).
Defining Hemp: A Fact Sheet
B otanically, hemp and marijuana are from the same species of plant, Cannabis sativa, 1 but from different varieties or cultivars. 2 However, hemp and marijuana are genetically distinct forms of cannabis that are distinguished by their use and chemical composition as well as by differing cultivation practices in their production. While marijuana generally refers to the cultivated plant used as a psychotropic drug (whether used for medicinal or recreational purposes), hemp is cultivated for use in the production of a wide range of products, including foods and beverages, personal care products, nutritional supplements, fabrics and textiles, paper, construction materials, and other manufactured and industrial goods. Hemp and marijuana also have separate statutory definitions in U.S. law.
Despite these differences, growing hemp has been restricted in the United States until recently, and the U.S. market has been largely dependent on imports for finished products and as an ingredient for use in further processing. Hemp’s association with marijuana placed its production under U.S. drug laws wherein all cannabis varieties, including hemp, were considered Schedule I controlled substances under the Controlled Substances Act (CSA). 3 Since the late 1950s, the U.S. Drug Enforcement Administration (DEA) has strictly controlled and regulated hemp production. Prior to the late 1950s, hemp in the United States was considered an agricultural commodity, and the U.S. Department of Agriculture (USDA) supported its production. 4
Restrictions on U.S. hemp production and marketing were relaxed by changes enacted in the 2014 farm bill (Agricultural Act of 2014, P.L. 113-79 ) and were further relaxed in the 2018 farm bill (Agriculture Improvement Act of 2018, P.L. 115-334 ). These changes provide further differentiation between hemp and marijuana in terms of farm policy and federal regulatory oversight.
The Food and Drug Administration (FDA) maintains oversight of hemp-derived consumer products under the Federal Food, Drug, and Cosmetic Act (21 U.S.C. §§ 301 et seq.). FDA’s jurisdiction includes hemp and hemp-derived products as a food and food ingredient, as well as an ingredient for use in body products, cosmetics, dietary supplements, and therapeutic products.
Hemp and marijuana are distinct in several key ways: (1) statutory definitions and regulatory oversight, (2) chemical and genetic compositions, and (3) production practices and use. This fact sheet describes these differences, which are summarized in Figure 1.
Figure 1. Differences Between Hemp and Marijuana
Source: CRS from various governmental and industry sources.
Statutory Definition and Regulatory Oversight
Congress expanded the definition for hemp in the 2018 farm bill (amending the 2014 farm bill definition of industrial hemp), further distinguishing hemp and marijuana under U.S. law. Hemp is codified in Section 297A of the Agricultural Marketing Act of 1946 (AMA, 7 U.S.C. 1621 et seq.) as follows: 5
the plant Cannabis sativa L. and any part of that plant, including the seeds thereof and all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers, whether growing or not, with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis.
As defined in statute, hemp must contain no more than a 0.3% concentration of delta-9 tetrahydrocannabinol (delta-9 THC)—marijuana’s primary psychoactive chemical. In general, a level of about 1% THC is considered the threshold for cannabis to have a psychotropic effect or an intoxicating potential. 6 Some suggest that cannabis with a THC level of greater than 1% be considered a drug varietal (e.g., marijuana), 7 with some suggesting that marijuana plants often have a THC level of 5% or more. 8 In the United States, hemp varieties or cultivars having less than 0.3% THC may be cultivated under USDA-approved license as hemp, while plant varieties or cultivars having higher amounts of THC may not be cultivated as they are considered to have too high a potential for drug use. 9
By contrast, marijuana (or “marihuana,” as it is spelled in the older statutes) is more broadly defined in the CSA and does not specify a permissible limit for THC or any other cannabinoid:
(16) The term “marihuana” means all parts of the plant Cannabis sativa L., whether growing or not; the seeds thereof; the resin extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds or resin. Such term does not include the mature stalks of such plant, fiber produced from such stalks, oil or cake made from the seeds of such plant, any other compound, manufacture, salt, derivative, mixture, or preparation of such mature stalks (except the resin extracted therefrom), fiber, oil, or cake, or the sterilized seed of such plant which is incapable of germination. 10
Marijuana is a Schedule I controlled substance under federal law, and, as such, the unauthorized manufacture, distribution, dispensation, and possession of marijuana is prohibited. 11 Cannabis that exceeds the 0.3% delta-9 THC concentration limit falls under the definition of marijuana and the CSA. THC levels in marijuana reportedly average about 10%, with a high of 30% concentration. 12 However, advancements in cannabis breeding have introduced plant varieties with even higher levels of THC and other cannabinoids. 13
The definition of industrial hemp enacted in the 2014 farm bill allowed for hemp cultivation under certain narrowly prescribed circumstances—namely, for research purposes by research institutions and state departments of agriculture in states with laws allowing for hemp production. Although hemp production was allowed in accordance with the requirements of the 2014 farm bill provision, other aspects of production were still subject to CSA regulations and DEA oversight, including the importation of viable seeds, which still required DEA registration according to the Controlled Substances Import and Export Act (21 U.S.C. §§951-971). This and other requirements were reinforced in a 2016 joint Statement of Principles on Industrial Hemp issued by DEA, USDA, and FDA. 14 The 2016 guidance also clarified DEA’s contention that the commercial sale or interstate transfer of hemp continued to be restricted. A May 2018 internal directive by the DEA later clarified that certain “products and materials that are made from the cannabis plant and which fall outside the CSA definition of marijuana (such as sterilized seeds, oil or cake made from the seeds, and mature stalks) are not controlled under the CSA.” 15 Accordingly, such products may be sold and distributed throughout the United States without restriction under the CSA or its implementing regulations. The 2018 directive, however, does not apply to cannabis extracts and resins. 16
The 2018 farm bill further expanded upon hemp policies in the 2014 farm bill by amending the CSA and removing hemp from the CSA definition of marijuana (21 U.S.C. §802(16)). 17 Removing hemp (as defined in AMA Section 297A) from the CSA—and thus removing it from being considered a controlled substance—effectively permits the cultivation, processing, marketing, and sale of hemp and any cannabinoid derived from hemp that is produced by an authorized grower in accordance with the 2018 farm bill, associated federal USDA regulations, and applicable state regulations. The 2018 farm bill also excludes THCs in hemp (as defined) from Schedule I of the CSA. 18 All other cannabis and cannabis-derived products remain a Schedule I substance under federal law and are thus subject to CSA regulations and DEA oversight, except for certain drug products approved by FDA. Regardless of whether a substance is hemp-derived, it is FDA’s view that it is unlawful to market food or dietary supplements containing cannabidiol (CBD) or other cannabinoids, as well as any products making therapeutic claims without FDA approval. 19
The 2018 farm bill also established a new regulatory framework to monitor compliance and regulate production under USDA’s jurisdiction. 20 The 2018 farm bill also contains an “interstate commerce” provision that prohibits states and Indian tribes from interfering with the transport of hemp or hemp products produced in accordance with the new USDA requirements through their jurisdictions. 21 Hemp is now also eligible for federal crop insurance programs, as well as USDA research and development programs. 22 These changes returned U.S. hemp production to the status of an agricultural commodity and thus eligible for USDA-supported farm programs, similar to the status it had in the United States before the late 1950s.
Chemical and Genetic Makeup
There are many different varieties of cannabis. Although industrial hemp and marijuana are both varieties of cannabis, they have been bred for different uses and can be distinguished by their chemical and genetic compositions. 23
Differences in Chemical Composition
The term industrial hemp dates back to the 1960s and generally refers to cannabis varieties that are grown primarily as an agricultural crop, such as seeds and fiber, and byproducts, such as oil, seed cake, and hurds. 24 Hemp is generally characterized by plants that are low in delta-9 THC, the dominant psychotrophic compound in Cannabis sativa. 25 In addition to its low THC content, hemp generally has high levels of CBD, the primary nonpsychotropic compound in Cannabis sativa. 26 Accordingly, a high ratio of CBD to THC might also be a metric used to differentiate hemp from other cannabis varieties. 27
THC and CBD are among the subclasses of cannabinoids and their 66 known variants in Cannabis sativa (see text box). 28 Cannabinoids refer to the unique chemical compounds produced in the plant, which are known to exhibit a range of psychological and physiological effects. 29 These compounds exist in both hemp and marijuana in varying amounts. THC is the primary psychoactive compound in cannabis; however, the plant contains multiple THC isomers and variants. 30 While some cannabinoids are psychoactive, others, such as CBD, are not considered to be psychoactive. 31 THC and CBD are considered to be among the most abundant cannabinoids in cannabis, and some consider both to be medically valuable. THC and CBD are also the most well-known and researched cannabinoids. Among the isomers of THC, properties may vary and not all have been well characterized. 32 The interaction between THC and other cannabinoids in the cannabis plant is also not well known.
More than 480 natural components are found within the Cannabis sativa plant, of which 66 are classified as cannabinoids. Cannabinoids are separated into the following subclasses.
Delta-9 tetrahydrocannabinol (delta-9 THC)
Number of known variants: 9
Delta-8 tetrahydrocannabinol (delta-8 THC)
Number of known variants: 2
Number of known variants: 6
Number of known variants: 5
Number of known variants: 7
Number of known variants: 7
Cannabinodiol (CBND or CBDL)
Number of known variants: 2
Number of known variants: 3
Number of known variants: 5
Number of known variants: 9
Other miscellaneous types of cannabinoids
Number of known variants: 11
Source: J. E. Joy et al., eds., Marijuana and Medicine: Assessing the Science Base, Institute of Medicine, 1999; and University of Washington, Alcohol and Drug Abuse Institute, “Cannabinoids,” June 2013 .
Differences in Genetic Composition
Scientific and genome research indicate that hemp and marijuana are neither genetically identical nor genetically similar. Although hemp and marijuana are from the same cannabis plant, available research supports the conclusion that selective breeding has resulted in two separate strains.
A 2015 study by Canadian researchers reports that “marijuana and hemp are significantly differentiated at a genome-wide level, demonstrating that the distinction between these populations is not limited to genes underlying THC production.” 33
A 2015 University of Minnesota study notes that marijuana and hemp “can be readily distinguished by the relative yield” of tetrahydrocannabinolic acid (THCA) in marijuana and cannabidiolic acid (CBDA) in hemp. 34 The study observed a “diversity of THCA and CBDA synthase sequences observed in the mapping population, the position of enzyme coding loci on the map, and patterns of expression suggest multiple linked loci.” The study also found that marijuana is distinguished from hemp by compounds that appear to have been “positively selected to enhance psychoactivity.” 35
The discovery of a single gene distinguishing two plant varieties suggests that the two plants are distinct. A 2011 Canadian study further concluded that “single nucleotide variant analysis uncovered a relatively high level of variation among four cannabis types, and supported a separation of marijuana and hemp.” 36 These studies find that available research and genome mapping suggest that hemp and marijuana are genetically separate and distinct plant varieties.
Genomic research in Canada supports the notion that over thousands of years of cultivation, cannabis farmers have “selectively bred Cannabis sativa into two distinct strains—one for fiber and seed, and one for medicine.” 37
Production Practices and Use
In general, hemp is grown and harvested differently from marijuana. Production practices among cannabis varieties vary with respect to cultivation, including plant height, density, and timing of their harvest. While marijuana is cultivated to promote the development of flowering tops and leaves of psychoactive cannabis plant varieties with elevated concentrations of THC, hemp is cultivated depending on its intended use across three different crops: fiber, seeds, and flower ( Table 1).
Table 1. Primary Hemp Crops: Fiber, Seeds, and Flowers
Desired Plant Material
Stalks (bast fibers and hurd/core fibers)
Dried (high in oil and protein)
Dried and cut (flower bud and floral material)
Dense spacing to discourage branching and flowering (35-50 plants/ft 2 )
Dense spacing to discourage branching and flowering (35-50 plants/ft 2 )
Well spaced (typically planted 3-4 feet apart on a 3-5 foot center)
Tall plants with small stalks and less leafy material
Plants with small stalks and less leafy material
Bushy plant with wide branching to promote flowers/buds (selecting female plants is ideal)
Typically using hay equipment (mow, field retting 2-3 weeks, then roll balling)
Must be harvested within a short window due to seed scatter issues
Harvesting is highly labor intensive, in part given possible degradation of plant material related to efforts to preserve the chemical properties of the plant’s flowering heads; also requires drying down to 10% moisture
1.0-5.5 tons per acre of dry matter (whole dry stems)
Avg: 800-1,000 lbs./acre (up to 1,600 lbs./acres)
NA (varies widely); one plant yields about one pound of dried material
$0.65-$0.75 per pound
$25-$200 per pound
About 8¢/lb. ($160/ton).
Return per Acre
Up to $700 per acre
Up to $1,200 per acre
Bast fibers used for paper, insulation, composites, and textiles; core fibers used for animal bedding, concrete, fiberboard, and oil absorbents
Foods and body products
Shelled seed and fines
Oil and seed cake
Extractions of plant resin (CBD, other cannabinoids)
Nutraceuticals and wellness products
Decortication, removing the tough woody interior (hurd) from the softer, fibrous exterior of the stalk (separating the bast and the hurd/core fibers)
Dehulling and pressing of dried hemp seed/grains
Requires extraction using a variety of methods, including lipid or alcohol/ethanol infusions, CO2 extraction, or extraction using other types of chemical solvents (hexane, butane), as well as solvent-free extractions; extraction may or may not involve heat decarboxylation
Source: CRS from various sources, including K. Pularski, “Hemp Industry Overview,” presentation at hemp conference hosted by the Greater Peoria Economic Development Council, Illinois, January 18, 2019.
Notes: Most figures are based on 2017 Kentucky crop data. Production data for other producing regions may vary. NA = Not available.
Cannabis is dioecious, meaning that there are separate male and female plants, each with distinctive growth characteristics. For drug production, the female flowers are more valuable, whereas male plants are used to produce hemp fibers. When cannabis is grown to produce marijuana, it is cultivated from varieties where the female flowers are specifically selected to prevent the return of separate male and female plants. 38 When cultivating marijuana, the female flowers are short and tightly clustered. In marijuana cultivation, growers remove all the male plants to prevent pollination and seed set. Some growers will hand-pollinate a female plant to get seed. This is done in isolation from the rest of the female plants. Encouraging monoecism (female-only plants) in marijuana cultivation requires the skill of a competent plant breeder and rarely occurs under noncultivated conditions. By contrast, when cannabis is grown to produce hemp fiber and seeds (using only male plants), the plant is discouraged from flowering, forcing it to grow taller with less branching.
Cannabis seeds generally fall into one of three categories: regular, feminized, or autoflowering. 39 Regular seeds produce both male and female plants at about a 50/50 ratio, but often male plants may be identified to avoid the fertilization of the female plants. Feminized seeds are specially treated plants to produce only female plants, generally by stressing a female plant to produce viable, genetically identical seeds without being fertilized by a male plant, resulting in female offspring only. Autoflowering seeds are crossbred hybrids that generally result in all female plants that often contain less THC. 40 Some seeds are being genetically and/or selectively bred to produce strains that have zero THC. 41
Preserving the genetic composition of each variety requires careful attention to the prevention of cross-pollination. Cross-pollination among the different varieties is a concern because cannabis plants are open (e.g., wind and/or insect pollinated), and thus cross-pollination is possible if the crops are grown in close proximity. Cross-pollination would result in unwanted characteristics in both industrial hemp and marijuana. For growers of marijuana, cross-pollination with hemp could significantly lower the THC content and thus degrade the value of the marijuana crop. Likewise, growers of hemp would seek to avoid cross-pollination with marijuana plants, especially given the illegal status of marijuana. If hemp varieties are grown in or around marijuana, the hemp would pollinate the female marijuana plant. Likewise, marijuana growers would not want to plant near hemp fields, because this could result in harvests that are seedy and lower in THC and thus degrade the value of their marijuana crops. Plants grown for oilseed are also marketed according to the purity of the oilseed, and the mixing of other genotypes would degrade the value of the crop. 42
Differences in the cultivation practices between marijuana and hemp generally result in different observable traits under field conditions. 43 Visual plant differences between hemp and marijuana generally include plant height (hemp is often encouraged to grow tall, whereas marijuana is selected to grow short and tightly clustered); cultivation (hemp is often grown as a single main stalk with few leaves and branches, whereas marijuana is encouraged to become bushy with many leaves and branches to promote flowers and buds); and planting density (hemp is often densely planted to discourage branching and flowering, whereas marijuana plants are well spaced).
In general, the period of seeding to harvest ranges from 70 to 140 days depending on its intended purpose, the cultivar or variety planted, and climatic conditions. Different cannabis varieties or cultivars may be harvested at different times depending on the growing area.
Recent advances in cannabis research and development, as well as plant breeding and the creation of new cultivars and hybrids, are resulting in plants that do not always precisely present these distinctive observable characteristics. 44 Specifically, some hemp plants are being grown to be short and bushy, encouraging larger flowers, often from high-CBD, low-THC hemp seed. Hemp plants grown for flower are planted less densely—about 3 to 5 feet apart—to encourage the plant to become bushy with many leaves with wide branching to promote flowers and buds. Similarly, marijuana’s high THC content is concentrated primarily in the flowers and to a lesser extent in the leaves.
The cannabis plant’s cannabinoids (e.g., CBD, THC) are generally concentrated not in the plant’s seeds but in the flowering head of the plant. 45 Specifically, the heads of the mature cannabis flowers and leaves contain the trichomes—a term that refers to the small resin-like hairs/glands of the flowering buds but may also cover the leaves, bracts, and stems of plants. 46 Trichomes—the plant hairs—are among the primary source of the plant’s cannabinoids. Cannabinoids may be present in other parts of the plant, including the seeds, but in lower quantities. 47 Cannabinoid concentration in hemp may also vary depending on the types of trichomes and secretory structures present. 48 Besides cannabinoids, cannabis trichomes produce other secondary metabolites, including terpenes and certain phenolic compounds, such as flavonoids. 49
In general, each cannabis plant yields approximately one pound of dried floral material available for extraction by chemical process ( Table 1). However, the percentage of extract generated per pound of dried material, as well as the quality and level of cannabinoids extracted, varies widely. Still, the flowers of the hemp and marijuana plant differ. Drug-grade cannabis also contains high resin concentrations, whereas fiber-grade cannabis generally has low levels of resin.
Hemp plants grown for fiber or oilseed are planted more densely—about 35-50 plants per square foot to discourage branching and flowering—than hemp plants grown for flower. For fiber and oilseed, the plant’s stalk and seed are the harvested products. 50 Available 2017 production statistics for Kentucky indicate that 1 acre of hemp yields between 800 and 1,000 pounds of seed, or between 1 and more than 5 tons of dry matter ( Table 1). 51
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In this report, cannabis refers to the plant species Cannabis sativa and all of its industrial, medicinal, and recreational varieties. The terms industrial hemp and hemp are used interchangeably, and the term marijuana refers to the plant used as a medicinal or recreational drug unless otherwise specified. The terms Cannabis sativa L denote use of the Linnean system of taxonomy.
Plant varieties and cultivars both refer to unique characteristic of a particular plant, but they differ overall: Varieties often occur in nature, and most varieties are true to type, meaning that seedlings grown from a variety will also have the same unique characteristic of the parent plant. Cultivars are cultivated varieties and not necessarily true to type, since certain traits have been selected by growers. See Cindy Haynes, “Cultivar versus Variety,” Iowa State University, February 6, 2008, https://hortnews.extension.iastate.edu/2008/2-6/CultivarOrVariety.html .
21 U.S.C. §§801 et seq.; Title 21 C.F.R. Part 1308.11.
Strictly speaking, the CSA does not make growing hemp illegal, but makes it illegal to grow without a DEA permit.
A definition of hemp was originally established in the 2014 farm bill and amended by the 2018 farm bill ( P.L. 115-334 , §10113). The 2014 farm bill defined industrial hemp to mean “the plant Cannabis sativa L. and any part of such plant, whether growing or not, with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis” (7 U.S.C. §5940(b)(2)).
See, for example, E. Small and D. Marcus, “Hemp: A New Crop with New Uses for North America,” in Trends in New Crops and New Uses, ed. J. Janick and A. Whipkey (Alexandria, VA: American Society for Horticultural Science Press, 2002).
F. Grotenhermen and M. Karus, “Industrial Hemp Is Not Marijuana: Comments on the Drug Potential of Fiber Cannabis,” nova-Institute, http://www.internationalhempassociation.org/jiha/jiha5210.html .
See, for example, M. Shipman, “Is Hemp the Same Thing as Marijuana?,” North Carolina State University, February 15, 2019, https://phys.org/news/2019-02-hemp-marijuana.html ; and D. Donnon, A. T. Kearney, “The New Green Rush,” presented at a Food Institute webinar, January 31, 2019.
E. Small and D. Marcus, “Tetrahydrocannabinol Levels in Hemp (Cannabis sativa) Germplasm Resources,” Economic Botany, vol. 57, no. 4 (October 2003); and G. Leson, “Evaluating Interference of THC Levels in Hemp Food Products with Employee Drug Testing” (prepared for the province of Manitoba, Canada), July 2000.
Generally, all cannabis varieties are commonly considered to be of a single species. However, not all researchers agree on a single taxonomy. Other cannabis species may include Cannabis indica (meaning from India) and its known subspecies. See, for example, R. C. Clarke and M. D. Merlin, “Cannabis Taxonomy: The ‘Sativa’ versus ‘Indica’ Debate,” HerbalGram, vol. 13, no. 4 (April 2016).
Based on sample tests of illegal cannabis seizures from December 2007 through March 2008. National Institute of Drug Abuse, “Quarterly Report, Potency Monitoring Project,” University of Mississippi, 2008.
See, for example, M. A. ElSohly et al., “Changes in Cannabis Potency over the Last Two Decades (1995-2014): Analysis of Current Data in the United States,” Biological Psychiatry, vol. 79, no. 7 (April 1, 2016): pp. 613-619.
81 Federal Register 156: 53395-53396, August 12, 2016; also DEA/USDA/FDA joint “Statement of Principles on Industrial Hemp,” August 2016.
DEA, “DEA Internal Directive Regarding the Presence of Cannabinoids in Products and Materials Made from the Cannabis Plant,” May 22, 2018.
81 Federal Register 240: 90194-90196, December 14, 2016. See also DEA, “Clarification of the New Drug Code (7350) for Marijuana Extract,” https://www.deadiversion.usdoj.gov/schedules/marijuana/m_extract_7350.html .
FDA, “Statement from FDA Commissioner Scott Gottlieb, M.D., on the Signing of the Agriculture Improvement Act and the Agency’s Regulation of Products Containing Cannabis and Cannabis-Derived Compounds,” press release, December 20, 2018.
See, for example, S. L. Datwyler and G. D. Weiblen, “Genetic Variation in Hemp and Marijuana (Cannabis sativa L.) According to Amplified Fragment Length Polymorphisms,” Journal of Forensic Sciences, vol. 51, no. 2 (2006).
See L. Grlic, “A Combined Spectrophotometric Differentiation of Samples of Cannabis,” United Nations Office on Drugs and Crime, January 1968. Hurds are soft inner core fiber of the hemp stalk. Hurds are woody in texture and mostly used in nonwoven items, including hempcrete and animal bedding.
R. C. Clarke and M. D. Merlin, Cannabis: Evolution and Ethnobotany (University of California Press, 2013), p. 255. A psychotrophic drug is capable of affecting mental activity, behavior, or perception and may be mood-altering.
U. R. Avico et al., “Variations of Tetrahydrocannabinol Content in Cannabis Plants to Distinguish the Fibre-Type from Drug-Type Plants,” UNODC Bulletin on Narcotics, January 1985; C. W. Waller, “Chemistry of Marihuana,” Pharmacological Reviews, vol. 23 (December 1971); K. W. Hillig and P. G. Mahlberg, “A Chemotaxonomic Analysis of Cannabinoid Variation in Cannabis (Cannabaceae),” American Journal of Botany, vol. 91, no. 6 (June 2004); and A. W. Zuardi et al., “Cannabidiol, a Cannabis sativa Constituent, as an Antipsychotic Drug,” Brazilian Journal of Medical and Biological Research, vol. 39 (2006).
Continued advancement in breeding and plant genetics, however, are resulting in cannabis varieties or cultivars that have more equal parts THC and CBD, making previous generalizations about the inverse relationship between THC and CBD concentration less relevant.
More than 540 phytochemicals have been described in hemp (see J. Gould, “The Cannabis Crop,” Nature, vol. 525, no. S2–S3 [September 24, 2015]). Other present compounds include certain terpenes and phenolic compounds, including flavonoids. See footnote 49.
Clarke and Merlin, Cannabis: Evolution and Ethnobotany, p. 255.
Isomers are molecules with the same chemical formula but distinct atomic structures.
Clarke and Merlin, Cannabis: Evolution and Ethnobotany . For example, cannabigerol, cannabichromene, and cannabidivarin are reported to be nonpsychotrophic.
See, for example, E. A. Carlini, “The Good and the Bad Effects of (-) Trans-Delta-9-Tetrahydrocannabinol (Δ9-THC) on Humans,” Toxicon, vol. 44 (July 2004), pp. 461-467. Other identified isomers of THC, such as delta-1 THC and delta-6 THC, may be related to delta-9 THC and delta-8 THC, respectively.
J. Sawler et al., “The Genetic Structure of Marijuana and Hemp,” August 2015, PLoS ONE, vol. 10, no. 8, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0133292 .
G. D. Weiblen et al., “Gene Duplication and Divergence Affecting Drug Content in Cannabis Sativa,” New Phytologist, July 17, 2015, https://doi.org/10.1111/nph.13562 .
Weiblen et al., “Gene Duplication and Divergence.”
H. van Bakel et al., “The Draft Genome and Transcriptome of Cannabis Sativa,'” Genome Biology, vol. 12, no. 10 (October 20, 2011), https://doi.org/10.1186/gb-2011-12-10-r102 .
ScienceDaily, “How Hemp Got High: Cannabis Genome Mapped,” October 24, 2011, citing vanBakel et al., “The Draft Genome and Transcriptome of Cannabis Sativa.”
Van Bakel et al., “The Draft Genome and Transcriptome of Cannabis Sativa.” In botany, dioecious describes plant varieties that possess male and female flowers or other reproductive organs on separate, individual plants.
I. Zeiler and C. Bussink, “The Cannabis Seeds Business,” draft report by researchers at the United Nations Office on Drugs and Crime, 2012.
Zeiler and Bussink, “The Cannabis Seeds Business.”
See, for example, BusinessWire, “GenCanna Announces First Patentable Non-GMO Hemp Genetics with 0.0% THC,” January 28, 2019.
An example of another plant whereby different crops are cultivated by selecting for different traits is sweet corn and field corn (or corn for grain). Corn may also naturally cross-pollinate and requires early selection and removal of plants before pollination based on certain plant traits. Intermixing plants of the two types of corn may result in cross-pollination and degradation of each crop.
G. D. Weiblen, University of Minnesota, presentation at the 2013 Annual HIA Conference, Washington, DC, November 17, 2013.
CRS communication with Duane Sinning, Colorado Department of Agriculture, February 2, 2016.
J. E. Joy et al., eds., Marijuana and Medicine: Assessing the Science Base, Institute of Medicine, 1999.
C. M. Andre et al., “Cannabis sativa: The Plant of the Thousand and One Molecules,” Frontiers in Plant Science, vol. 7, no. 19 (2016).
See, for example, S. A. Ross et al., “GC-MS Analysis of the Total Delta9-THC Content of Both Drug- and Fiber-Type Cannabis Seeds,” Journal of Analytical Toxicology, vol. 24, no. 8 (November-December 2000), pp. 715-717.
Hemp trichome types include unicellular nonglandular trichome, cystolythic trichomes, capitate sessile trichome, capitate-stalked trichome, simple bulbous trichome, and complex bulbous trichome.
Ross et al., “GC-MS Analysis.” Terpenes refers to certain phytochemicals (or biologically active compounds) found in plants, generally associated with a plant’s aromatic organic compounds. Phenolic compounds refers to a large class of secondary metabolites found in most plants.
The stalk provides two types of fibers: (1) the interior or core short woody fibers (or hurds) and (2) the outer portion of the stem, which contains the long bast fibers (referring to the cellulosic fibers that grow on the outside of the hemp plant’s stalk, which are used for animal bedding and oil absorbents, among other uses).
Previous estimates from Agriculture and Agri-Food Canada suggest that about 700 pounds of seed can be pressed into about 50 gallons of oil and 530 pounds of meal, whereas 5,300 pounds of hemp straw can be transformed into about 1,300 pounds of fiber .