cbd hemp plantDecember 15, 2021
The researchers examined different types of cannabis, including drug-type varieties that produce large amounts of psychoactive tetrahydrocannabinol (THC). Plant breeding has increased the THC level to the point where it can account for up to a quarter of a plant’s total weight. The scientists found that breeding high-THC plants with hemp-type plants can swap a few genes and make a new plant that produces high levels of CBD instead.
Researchers say this means that when high-CBD plants are grown to full maturity, farmers interested in producing hemp for CBD run the risk of their crop crossing over the federal, legal limit of 0.3% THC.
After assembling a complete genome from a new breed of cannabis, University of Minnesota and Sunrise Genetics researchers found that high-CBD “hemp” plants have a mostly marijuana genome.
“Over the past decade, we’ve seen a surge in demand for CBD and we wanted to better understand how plant breeders created high-CBD plants to meet rising demand,” said study co-author George Weiblen, who is a professor in the College of Biological Sciences (CBS) and the science director at the Bell Museum.
Published in the journal New Phytologist, the researchers found that high-CBD plants inherit about 90% of their genes from drug-type cannabis and the rest from hemp. Traditionally, cannabis plants are split into two varieties: a drug-type grown for psychoactive or intoxicating properties (i.e., marijuana) and a hemp-type used to make industrial products like fiber.
“This poses a challenge, though,” said study co-author and CBS graduate CJ Schwartz of Sunrise Genetics. “The genes that allow for the production of CBD are also a bit ‘leaky.’ This can result in about 5% of the product ending up as THC instead of 100% CBD.”
“These high-CBD plants are genetically marijuana for the most part and they can’t be expected to meet the legal definition of industrial hemp in every situation,” said Weiblen. “This means that CBD products — such as flowers, extracts and edibles — that are labeled ‘hemp’ could be incorrectly labeled and falsely branded. Fiber hemp and products made from hemp seeds, however, are drug-free.”
Just like a marijuana grower, a hemp farmer growing for high concentrations of CBD would want to remove the male plants from the field or facility before pollination. This allows for less seed and higher concentrations of phytocannabinoids in each plant. Under this growing condition, hemp grown for phytocannabinoids like CBD commonly resembles marijuana production patterns.
For this reason, certain states have passed legislation for recreational and/or medical marijuana as well as the legal production of industrial hemp. The 2014 Farm Bill protects hemp production for research purposes and pilot scales within universities and State departments of agriculture. This is a federal bill.
Hemp and marijuana are both cannabis. But, hemp and marijuana are different varieties of the Cannabis sativa species.
The major similarity when growing hemp and marijuana is when growing for the cannabinoids. In hemp’s case, farmers grow for the CBD and other minor cannabinoids, but legally require less than 0.3% of the cannabinoid THC. As for marijuana, unless growing for a particular ratio of THC : CBD, growers want the highest concentrations of THC and CBD possible. Because these production schemes both desire high concentrations of cannabinoids found in the floral material; the current growing conditions are similar.
First and foremost: Hemp is not marijuana. Marijuana is not hemp. This is one of the most important facts to KNOW AND SHARE because people are unaware that they are different. Oftentimes people believe that hemp is the male plant of marijuana. This is false.
Growing for Phytocannabinoids.
In the regulatory realm, technically anything containing (even the minutest) concentrations of tetrahyrdocannabinol (THC) are regulated under the Drug Enforcement Agency’s Controlled Substance Act; however, the federal government allows states to create their own cannabis policies.
This confusion exists because marijuana was created by selectively breeding Indian hemp for Tetrahyrdocannabinol (THC). THC is the major differentiating factor between hemp and marijuana.
Conversely, European growing conditions for CBD resemble fiber conditions and the crop is often dual harvested for fiber and CBD. This CBD is produced at lower concentrations in the tops of fiber varieties. This method creates a dual-purpose production system and resembles densely-packed hemp fiber production as opposed to bushy, flowering marijuana.
The 2015 and 2016 Omnibus Bills (Federal Spending Bill) also contain strategic language that prohibits the DEA from using federal dollars to block research, production and sales of both hemp and marijuana.
What is the difference between hemp and marijuana?
Market information is too weak for prediction or advice but information is improving such as with a USDA ERS Feb 2020 report.
The CBD levels can be much reduced by cross-pollination with wild or non-CBD hemp. The CBD plants must be well-separated by distance or time of pollination from hemp weeds or another hemp crop. Also, a few rows of corn or forage sorghum can planted around the plots to reduce pollen flow.
Hemp CBD varieties have not been well-validated for Nebraska but possibilities may include ‘Abocus’, ‘Autopilot’, ‘Boax’, Cherry Wine, Cherry Blossom, Cobbler, and Sweetgrass for high pharmaceutical-grade CBD yield but having less than 0.3% THC.. High CBD varieties are generally grown only as female plants, as the combination of male and female plants leads to seed production and decreased CBD yield. Breeders continue to improve the processes for creating stable feminized seed. Farmers need to be wary of the source of their feminized seed stock and to check test results for validation of feminized seed.
The ground-up plant material is soaked in grain alcohol or ethanol to extract the CBD oil. After soaking, the mix is pressed to extract the liquid. The alcohol is then evaporated off leaving the CBD oil.
Hemp grown for CBD is a high-value crop grown more as a horticultural than as an agronomic crop. It has a high labor demand, putting US production at a disadvantage with production in China and other countries with relatively inexpensive labor.
Drying the plant material is a major operation as the water content is high when harvested. To reduce the quantity to be dried and handled for CBD production, the woody stems may be removed for land application, composting or dried separately for fiber production. Artificial drying at up to 100 o F should be continuous flow but the temperature of the plant material should not exceed 75 o F. Suspending plants or branches upside down by wires indoors out of the sun and with good air movement for air drying at up to 75 o F is a common practice if the harvest is not too large.
Farmers need to know state regulations for testing hemp for CBD and THC. The Nebraska Department of Agriculture (NDA) regulations for industrial hemp production have been approved by USDA. Plant sampling by NDA staff to test for THC needs to be within 15 days before the date of harvest with the grower present during sampling. If the THC level is >0.3% by dry weight, the crop will not meet the legal definition of industrial hemp and need to be destroyed. Again, THC is expected to increase with stressful growing conditions.
Drying for smoke able buds is an option. Smoking of CBD is reported to be more effective than oral consumption. The buds are preferred but some upper leaves may be included. Well-dried material can be kept and sold in sealable plastic bags or glass jars.
CBD-containing products marketed in the US range from cosmetics to chocolate bars to bottled water to pet treats, all with no regulation. The Food and Drug Administration warned marketers of CBD products against the use of non-validated health claims to sell their products. In June 2019 the FDA approved the first CBD-based drug, called Epidiolex, to treat seizures caused by extreme types of epilepsy. The efficacy of CBD for treatment of chronic pain, neuro-inflammation, anxiety, addiction, and anti-psychotic effects has not been well-validated by clinical research.
The highest concentration of CBD is in the bracts of female flowers but CBD oil may be extracted from the whole plant. Harvest may be by topping plants for the harvest of mostly leaves and flowers, by picking the leaves and flowers from the plant, or by taking most of the plant cut at 8-12” above the ground. The whole plant harvest may be by shredding such as with a silage chopper or by keeping the plant intact.
CBD varieties have short plants with much branching, growing as squat bushes. The suggested spacing at this time is 2-4 feet x 6 feet. Planting practices may change for higher plant densities when seed supply is sufficient to greatly reduce the cost of seed. Given the high cost of seed, seedlings should be produced in a greenhouse for transplanting. If planting more than five acres, machine transplanting is recommended which may allow transplanting 2 acres per day. Plants can also be produced from cuttings with similar vigor and productivity compared to plants from seedlings. Propagation from cuttings may improve plant uniformity and is a means to all-female plants. The potting mix for greenhouse production of seedlings is important but needs to be well-drained with good available water holding capacity and nutrient supply. The mix probably should include sandy loam soil, perlite, and some organic material.
University of Nebraska-Lincoln Extension information typically is based on the interpretation of research information from Nebraska or elsewhere in the Midwest. However, such information is not available for hemp production due to previous restrictions on research in the U.S. This publication relies heavily on research findings from Europe and Canada and learning from growers’ experiences. See more stories in this series at https://cropwatch.unl.edu/tags/hemp.
Demand for CBD, a non-psychoactive compound derived from hemp, has soared for un-validated treatment of many conditions and illnesses. However, an approximate 75% plummet in prices for the CBD feedstock during 2019 indicates that the supply exceeded demand.
For information on budgeting for hemp grain, fiber and CBD production, see worksheets from Pennsylvania State University and from the University of Kentucky.