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Last year, an acre of Sarah Kelley’s hemp crop tested “hot” above the legal tetrahydrocannabinol (THC) limit of 0.3%. Although it contained 0.4% THC—just 0.1% above the legal limit—she and her boyfriend, Jamie Degenhardt, who together co-own Sarah’s Garden in rural Greenwood, Wisc., had to burn the entire acre. Kelley says, “It was quite a bit of a loss.”

She says she was surprised the acre tested hot—she used one of her two main strains, as well as the same cow manure and the same worm castings as on her other four acres of hemp. But now, in retrospect, she thinks an irrigation of manure tea on that one acre may have caused more THC to accumulate in the crop.

“This year, we didn’t use as much cow manure as last year, and we’re using [more] worm castings instead,” she says. “We’re going to test a little bit earlier instead of trying to reach the full maturity level. That’s when you get a little bit leery of testing hot.”

Kelley and Degenhardt process their own biomass into finished cannabidiol (CBD) products, then sell them via wholesale, e-commerce and their own Greenwood storefront. Kelley says her lost hot crop totaled about 600 pounds, which she estimates would have yielded roughly $5 per gram of CBD extract, equivalent to “about a $20,000 loss in CBD bulk extract.”

Between both hot crops and feral hemp posing cross-pollination issues, Kelley says Wisconsin seems like “the wild west of the hemp industry.”

“Everybody’s trying to figure out their own boundaries,” Kelley says.

However, Kelley’s is a relatable tale, mirroring what many growers across the U.S. are experiencing with testing hemp for THC levels. Concrete federal standards on when and how to test will fall into place in 2021, as state hemp programs like Wisconsin’s that are still operating under the Agricultural Act of 2014 (the 2014 Farm Bill) adjust themselves to be in accordance with the Agriculture Improvement Act of 2018 (the 2018 Farm Bill) and the impending final rule from the U.S. Department of Agriculture (USDA).

Not everyone is pleased with the changes that are likely to come down the pike, as evidenced in formal public and interview comments regarding the interim final rule issued last fall. Hemp Grower spoke with industry specialists whose perspectives run the gamut on the feasibility of a 0.3% limit and how growers can contain THC levels in 2021 and beyond.

Raising the Standard

A strong consensus is emerging in support of hemp testing standardization—a perspective echoed in thousands of public comments on the USDA’s interim final rule. (See below.) In several interviews, industry stakeholders were quick to mention that some labs and hemp brokers allegedly fudge numbers on their certificates of analysis (COAs).

“[Hemp growers] would like to see high numbers in the case of CBD, low numbers in the case of THC. In the medical arena, they’d like to see high THC numbers and maybe no CBD,” says Paul Daley, Ph.D., chief science officer at cannabis company California Cannabinoids and former consultant with Steep Hill, which claims to be the first U.S. commercial cannabis testing lab. “The laboratories, of course, are motivated to keep their clients, so there is an inherent risk of bias in numbers that you only can get around with scrutiny by regulatory agencies.”

Information on COAs can help growers determine if a lab is trustworthy, says Craig Schluttenhofer, Ph.D., research assistant professor of natural products at Central State University in Xenia, Ohio. COAs should include the lab’s address and contact information, the name of the person who performed the test and their signature, as well as a sample number.

Furthermore, the interim final rule states that labs must be certified by the Drug Enforcement Administration (DEA) to test hemp. The DEA, Schluttenhofer says, is well-versed in handling cannabis, and using their practices can “help weed out any of the questionable labs.” What this will look like in the future, however, remains unclear. In February, the USDA issued a temporary revision of the rule and stated that “testing can be conducted by labs that are not yet DEA-registered until the final rule is published, or Oct. 31, 2021, whichever comes ?rst.”

“I know there’s been a lot of pushback from labs needing that certification and concerns about how many labs the DEA will approve,” Schluttenhofer says, adding that he understands those concerns. However, he says, additional requirements from the DEA, or more preferably from the USDA, will help improve the industry overall.

When it comes to testing methods, the interim final rule states that THC levels must be tested either through high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography (UPLC), gas chromatography (GC) or a “similarly reliable” method. According to the USDA, these offer accurate results, as they convert delta-9 tetrahydrocannabinolic acid (THCA) into THC for the total THC concentration.

ACS Laboratory in Sun City Center, Fla., uses high-performance liquid chromatogram-ultraviolet (HPLC-UV) detection to test the potency of hemp flower clipped from the field, says Roger Brown, founder and president.

“There are a lot of cannabis-testing labs out there that buy the equipment, think they can just push a button, and right away, go and get their results,” Brown says. “It takes a lot more than that, and it’s sometimes a lot more complicated, like knowing the right equipment to choose, knowing how to read the retention times and the peaks on the results, knowing when your results are wrong and to be able redo them.”

Daley, having worked in environmental chemistry before entering the cannabis industry, says, “The testing environment for [soil and water] samples was vastly more rigid than anything we saw in [high-THC] cannabis until comparatively recently.” Those recent cannabis testing requirements in California and other states include “more detailed reporting of limits of detection,” “participation in performance tests” and “blind comparisons.”

The technology side of that same market saw a similar trajectory. “The early days [of commercial cannabis testing] were confined to gas chromatography,” Daley says. “Liquid chromatography came in a little bit later, which is now sort of a more routine method for cannabinoids. Terpenes came in much later yet.”

The interim final rule requires labs to report the measurement of uncertainty for a given type of testing, Schluttenhofer says. He says this is to the growers’ advantage because if these requirements weren’t in place, growers would have to take close but failing tests at face value and destroy their crops. According to the interim final rule, “Laboratories should meet the AOAC [Association of Official Agricultural Chemists] International standard method performance requirements for selecting an appropriate method.”

“There are probably going to be labs using several different testing methods,” Schluttenhofer says. “But if [multiple labs] are using the same method, they should wind up with consistent results. Generally, even between different standardized methods, to do them properly, you’re probably going to wind up with minimal variations in between the two standards or more [after accounting for the measurement of uncertainty] … just because, realistically, if the standard’s working as it is, it should be accurately detecting what’s there.”

Why 0.3%?

This year, Sarah’s Garden is growing on the same five acres again. Because THC levels can change over time, Kelley says she plans to harvest earlier than last year; when exactly that will be depends on the genetics of her hemp. As the calendar flips from late summer into early autumn, the perfect time to harvest becomes a delicate moving target.

Raising the federal THC limit of 0.3% to 1.5% would be helpful, she says. Doing so, however, is beyond the hands of the USDA and would require an act of Congress, since the limit is written into law in the 2018 Farm Bill, Schluttenhofer says.

“I’m just the grower trying to make a profit off a new crop,” Kelley says. “This is our third year growing. It’s not like we’re actually seasoned cannabis growers; we’re just learning here on the go. Hopefully, it’ll be worth the hassle.”

Kelley is not alone in her hope for a fruitful learning curve this year. For now, the hot crop conversation is fraught with opinions on the future of the industry.

Schluttenhofer says there is more to consider about the 0.3% limit and which varieties it allows growers to cultivate. Currently, the 0.3% limit allows for hemp product sales to Canada and other countries with the same limit. (Growers in Europe have an even lower 0.2% limit.) This may not be possible with a higher THC limit. Furthermore, he says it isn’t clear at which point THC levels cause intoxication.

The 0.3% THC cap comes from a plant taxonomy research article published in 1976 in Taxon. Even then, decades ago, the authors pointed out that their figure is not based in any overt scientific reasoning. “It will be noted that we arbitrarily adopt a concentration of 0.3% [delta-9 THC] (dry weight basis) in young, vigorous leaves of relatively mature plants as a guide to discriminating two classes of plants,” the article says. “This is based on standard-grown material in Ottawa in gardens, greenhouses and growth chambers, and of course on our analytical techniques.”

In 2019, researchers at Cornell University’s School of Integrative Plant Science began to home in on the ratio of CBD:THC production in cannabis plants. Larry Smart, project lead of the school’s Hemp Research Team, says the two compounds are locked together in development. Limiting THC content will invariably limit CBD content.

“We’ve analyzed cannabinoids from a lot of different samples, and that average ratio falls around 22:1, which is critical now, considering the USDA guidelines pretty strictly limit production to 0.3% total potential THC,” Smart told Hemp Grower earlier this year. “In order to stick to that threshold, growers will not be able to produce much more than 6% to 7% CBD.”

Ultimately, this ratio becomes a delicate balancing act for growers interested in maxing out CBD production for the consumer market.

This is where calls for a 1% or even 1.5% THC limit are coming from. With a bit of leeway on the allowable THC content, hemp farmers may be able to comfortably stretch their CBD production to meet demand—or, at the very least, find some peace of mind as the harvest season looms.

Time Flies

For 2020, Wisconsin has joined at least 24 other states in continuing to work within the regulatory framework of its hemp research pilot program (allowed for qualifying states in the U.S. for just this one last planting season in 2020). Kelley and the more than 1,200 other growers in her state will have a 30-day window to get their crops tested before harvesting this fall.

Courtesy of Sarah Kelley
Sarah Kelley (right in photo at right) and Jamie Degenhardt (left) of Sarah’s Garden process their own biomass into finished CBD products, then sell them via wholesale, e-commerce and their own storefront.
Courtesy of Sarah Kelley
Courtesy of Sarah Kelley

But after Nov. 1—and for hemp growers already working in states following the 2018 Farm Bill—the interim final rule grants only a 15-day window for testing. Public comments on the rule have zeroed in on this new time crunch as a likely problem later this year.

Brian Smith is the CEO of Big Sur Scientific, which manufactures on-site analyzers for hemp farmers. He’s spent the past year looking at test reports from different states, and he’s now warning of a bottleneck awaiting the industry at the 2020 harvest.

“I’ve heard horror stories from last year of farmers waiting for weeks or months for data, and that’s not fair,” he says. “Of course, the crop changes over time. If you take the sample now and test it three weeks later, that data is no longer relevant and that kind of folds back to the labs not having the testing capacity.”

Daley says: “This is a little out of my wheelhouse, but I have heard that, for instance, higher THC levels will build up late in what could be a harvest window. So, it’s sort of a game you have to play. If you can afford to do analysis out at the farm—and it’s, say, a $15,000 investment to have an HPLC—but if it made you $100,000 in a year, it’d probably be worth it. You could time your harvest to avoid a window where THC is building up.”

New Regulations

A major question on the minds of many growers who are still operating under state pilot programs is if they will be able to meet the 0.3% THC requirement under the sampling and testing measures of the interim final rule, and then a subsequent final rule.

Schluttenhofer, who previously worked at the University of Kentucky, points out that the Kentucky Department of Agriculture (KDA) has a 0.399% limit of tolerance for total THC.

Strains, according to a KDA document, “may be excluded from the KDA Hemp Licensing Program if: a) more than 50% of Pre-Harvest Samples’ test results for a given Variety of Concern are above 0.3000% delta-9-THC, b) a Pre-Harvest test result is equal to or greater than 1% delta-9-THC, or c) a Post-Harvest test result is equal to or greater than 0.4000% delta-9-THC.”

“Right now, because they have that leeway, the growers know that, and [some] push that [limit],” Schluttenhofer says, referring to the varieties they can grow. “[Those are] not necessarily the kind of practices that the industry needs to be doing anyways.” Ultimately, a clearly defined THC limit will improve the consistency of genetics available to growers across the U.S. Once Kentucky growers begin operating under the interim final rule, he says he doesn’t think they should have a problem growing hemp under the 0.3% THC limit.

Stresses on a hemp plant also influence its THC levels, Brown says, so growers have to pay attention to what occurs in different fields or different parts of a field.

“Is more water or less water, more nutrients, less nutrients, more sun, less sun going to stress the plant?” Brown asks. “You really don’t know until you have experience with growing on that farm.”

After 2019’s hot crop, Kelley says she plans to take her hemp to independent labs for third-party tests once or twice this August, prior to the state test.

For CBD producers, she says, “Then, ... you [should] third-party test your product that you made from that crop to [show that it’s] a reliable source of CBD,” she says. “If you don’t have that third-party test, people typically don’t want to buy your products.”

To prepare for state testing, Daley says growers can better understand their THC levels by submitting samples to multiple labs and seeing variability among results. He adds that labs need to step up to educate growers on what quality assurance data means.

“As more regulation creeps in and more people get stuck with material that they have to either remediate or destroy, there will be enough noise that hopefully the education and the strictness of the evaluation of labs will increase in parallel,” he says.

Eric Sandy is digital editor of Hemp Grower and sister publication Cannabis Business Times.

Patrick Williams is senior editor of Hemp Grower and sister publication Cannabis Business Times.