The Root of it All

The short and skinny on industrial hemp

By Jeremiah Vardiman
Posted 11/26/19

Wyoming farmers are always exploring for future markets and crops that can be produced here. The most recent focus has been on industrial hemp production. Currently, industrial hemp is not legal to …

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The Root of it All

The short and skinny on industrial hemp


Wyoming farmers are always exploring for future markets and crops that can be produced here. The most recent focus has been on industrial hemp production. Currently, industrial hemp is not legal to grow in Wyoming until the United States Department of Agriculture (USDA) approves Wyoming’s state plan for industrial hemp regulations and guidelines.

So what is hemp? Industrial hemp is an annual herbaceous plant that is classified in the family cannabaceae, which also includes hops and hackberries. Hemp (cannabis sativa L.) is related to marijuana, but unlike marijuana only contains trace amounts of THC; THC is the psychoactive component in marijuana that gets a person “high.” The legal classification of hemp is cannabis with THC levels at or below 0.3 percent, while marijuana is cannabis with THC levels above 0.3 percent (usually 3 to 15 percent). In other words, hemp would not be a good choice for psychoactive use.

Hemp is an erect bushy herbaceous plant that is dioecious and photoperiod sensitive.

Dioecious means that there are female plants and male plants, thus both plants are needed for seed production. There are a few modern cultivars that are monecious, which means there are male and female flowers on the same plant, however, it is not the norm. Interestingly enough, male and female plants cannot be distinguished prior to flowering.

Male plants are taller and spindlier than the female plants, and die directly after shedding all their pollen. Male plants can produce up to 350,000 grains of pollen per flower. However, the pollen viability decreases after three days. One important characteristic is that hemp is a wind-pollinated plant, with research documenting pollen moving up to 10 miles away from the plant.

It is also a photoperiod sensitive plant, which means that the plant is triggered to reproduce based on the length of daylight. Hemp will not start forming flowers until day length is less than 12 hours. This also means that the plant will mature approximately the same time each year, almost no matter when it was planted. Hemp is comparable to corn in terms of maturity, approximately 85 to 115 days.

Hemp can be grown for three general categories: fiber (ropes, nets, canvas, twine, etc.), grain (used as seed, food, feed or oil), and cannabinoids (CBD oil for medicinal and health products). Typically hemp is grown for one of the three categories. Hemp can be grown for multiple purposes, though this usually results in lower quality commodities to market which, in turn, fetch lower prices. Hemp grown for fiber and grain is produced from seed, while cannabinoids are generally produced from clones.

Current grain equipment, such as grain drills and combines, can be used for the planting and harvesting of hemp seeds. Hemp seeds should be planted 0.5 to 1.25 inches with a 6 to 7 inch row spacing in well drained, medium-textured soils. Seeds germinate best in soil temperatures around 50 degrees Fahrenheit and require 20 to 30 inches of available water per year.

In contrast, high quality cannabidiol (CBD) is generally produced from clones and only from female flowers. At this time, hemp breeders are still fine tuning the genetics for CBD. The most consistent high quality CBD is generally not produced from seed because the genetics for high CBD decreases during the cross pollination process when the seeds are created. Currently, the primary way to keep the high quality CBD genetics is by cloning the parent plant. Clones are produced asexually (not sexually) with cuttings made from a parent plant, which duplicates the plant with the same genetics. Hemp grown for cannabinoids are produced under more horticultural practices, which spaces clones on a 4 foot grid system and is conducive to drip irrigation systems. This type of cultivation can be grown inside a greenhouse or in the field. Indoor production is most likely a container production system, while field production is in beds with or without plastic mulch.

The complexities of hemp production arise when production of various purposes are grown in the same area, mainly because of cross pollination issues. Cross pollination can occur between plants grown for fiber, grain and cannabinoids. For example, cannabinoid growers only want un-pollinated female flowers, but grain and fiber crops grown in the surrounding area could jeopardize this crop because of the pollen blow (pollen in the wind).

Due to these factors, stringent management techniques are utilized to create appropriate isolation zones to keep the purity of the crop viable. These isolation zones can be a radius of 3 to 10 miles around the specific field, depending on what is established by the regulations in the state. These isolation zones are beneficial, but also can limit what growers are able to produce within those isolation zones. Even hemp weeds — which are hemp plants that have escaped cultivated fields, such as in irrigation ditches and fence rows — have an impact on the crop production and the potential loss of a viable crop because of these isolation zones. This issue is compounded even further in states that have legalized marijuana, such as Colorado, because hemp plants can also cross pollinate with marijuana plants as well.

The potential of another crop in Wyoming is on the horizon and so are the risks. However, this crop is not legal to grow within Wyoming until the USDA approves the Wyoming Department of Agriculture’s hemp regulation plan and that regulation is set forth by the state. The hemp industries and some producers are optimistic that this will occur for the 2020 crop year.

(Jeremiah Vardiman is an agriculture and horticulture extension educator with University of Wyoming Extension. He is based in Powell.)