Preparing for the New Hemp Rules-Consider Your Genetics

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hemp growing in field

Hemp field in western North Carolina.

4/9/2020 – Licensed NC hemp farmers are producing hemp under the rules and guidance of the NC Industrial Hemp Pilot Program until October 31, 2020. This is good news for many people because for our established hemp farmers and others working with the industry, it’s “business as usual”. But on November 1, 2020, the rules will change. As of that date we will all be operating under the U.S. Domestic Hemp Production Program (often referred to as the Interim Final Hemp Rule) in some form or fashion. We don’t yet know if North Carolina will have its own hemp program or if we will operate directly under the USDA program, but regardless, there will be some serious changes that we should take this growing season to prepare for.

USDA Hemp webpage

The biggest issue that NC hemp farmers need to start preparing for is that as the federal Interim Hemp Rule stands now, THC compliance testing for hemp will take place within 15 days of the anticipated harvest date. This is MUCH later than when testing is taking place in North Carolina right now. Presently, N.C. Department of Agriculture and Consumer Services collects samples for THC compliance testing when the hemp plants are at about 50% flowering. In the research hemp plots in my program last year, that was three to five weeks before harvest. If we had been operating under the new federal ruling, our plants would have been allowed to grow and mature for another one to three weeks before being tested. Since THC continues to rise as hemp plants mature, plants that met the 0.3% THC limit at 50% flowering, might well have been over that limit one to three weeks later.

A hemp floral sample being cut from a hemp plant in the field

A hemp compliance sample being collected.

THC and cannabinoid levels are mainly determined by genetics. Many of us still think that environmental factors, location, stress, time of planting, and seasonal differences also play a role, but recent research shows that genetics is the primary factor affecting THC and cannabinoid levels.

At NC State University, we have conducted hemp strain (variety) trials across the state for several years. We looked at growth, plant architecture, floral and biomass yields, and THC and cannabinoid content. The 2019 Hemp Strain Testing Results can be found online. Keep in mind that the THC and CBD levels reported in these studies are from harvested material at full maturity. Those plants, of course, were more mature than when the federal compliance testing would have taken place, but since the goal of the later testing is have harvested material that is below 0.3% THC, I want to show you how the strains we grew tested out at harvest.

Table of hemp strains and THC and CBD levels

THC and CBD test results from the 2019 Henderson County, NC hemp strain trial.

Note that all but one strain was over 0.3% THC at harvest. Also note that harvested material of three of the strains was over 0.5% THC (the significance of that is explained below).

Under our NC Pilot Hemp Program, if hemp passes the compliance test at 50% flowering, i.e., was 0.3% total THC or less, the harvested, mature material is still considered compliant even if it tests out at over 0.3% total THC. That is not the case under the new federal rules. It is stated clearly that “State and Tribal plans must incorporate procedures for sampling and testing hemp to ensure the cannabis grown and harvested does not exceed the acceptable hemp THC level.”

The USDA does recognize that even if you carefully select the strains that you are going to grow, follow best agricultural practices, and pass the THC compliance test, that your hemp may still “go hot”. They address that here: “We believe that a hemp producer in that scenario has exercised a level of care that a reasonably prudent person would exercise if the plant does not have a THC concentration of more than 0.5 percent on a dry weight basis. USDA arrived at that percentage by examining the test results of samples taken from several States that have a hemp research program under the 2014 Farm Bill and by reviewing results from plants grown from certified seed as well as uncertified seed and tested using different testing protocols. Under this scenario, although a producer would not be considered “negligent,” they would still need to dispose of the plants if the THC concentration exceeded the acceptable hemp THC level.” In other words, even if you pass the THC compliance test, if your harvested hemp material is over 0.3% (plus the measurement of uncertainty provided by the lab) but less than 0.5%, it still needs to be destroyed. If your harvested material tests out over 0.5% total THC, you will receive a negligent violation. Three of our strains did that last year!

Woman in hemp field

NCSU research assistant in research hemp field

There is always the chance that the USDA will change the 15-day harvest window for THC compliance testing. We know that they received many comments about how difficult that will be to accomplish, but based on all the information I am receiving, they are not going to change the 0.3% total THC level for legal hemp. So, I strongly recommend that you start practicing this year to grow and harvest hemp that will be legal under the new rules. Carefully select the strains you grow, follow best management practices during production and drying to keep THC low, and consider testing frequently as you near harvest to learn at what stage your plants go hot (which hopefully, they don’t!).

I wish you success in your hemp growing this year. Remember that even though we may not be in our offices right now, Extension is still here for you. Most of us are working remotely and extension specialists and agents can assist you in many ways. We have lots of Farming Resources for COVID times and each County Extension Center has staff and resources to help you. Stay safe.