Meet the Experts

JANNA BECKERMAN, Ph.D.

Professor, Botany and Plant Pathology, Purdue University

Janna Beckerman is an extension plant pathologist at Purdue University with a concentration in specialty crops (any crop in Indiana besides corn, beans or wheat). Her team has been growing hemp since 2014 and has partnered with several Indiana farmers for research through the U.S. Department of Agriculture (USDA) and the state’s hemp program. Beckerman and her team’s research in hemp has been published by the American Phytopathological Society as well as Elsevier’s Crop Protection.

RAYMOND CLOYD, Ph.D.

Professor/Extension Specialist, Kansas State University Department of Entomology

Raymond Cloyd’s expertise is based on decades of experience in the horticulture and agriculture industries and centers on pest management in greenhouses, nurseries, landscapes, turfgrass, conservatories, interiorscapes, Christmas trees, fruits and vegetables. His major clientele includes homeowners, master gardeners, and professional and commercial operators.

SHELBY ELLISON, Ph.D.

Assistant Faculty Associate – Industrial Hemp & Carrot, University of Wisconsin-Madison Department of Horticulture

Shelby Ellison’s work in hemp started in 2019 as she discovered a need for more training on the crop at universities. Ellison requested permission to teach a hemp science course and acquired a grower’s license last year to learn how to grow hemp herself. She has since collaborated with multiple researchers at UW-Madison on multiple small plots of hemp in Arlington, Chippewa County and Buffalo County to focus on hemp for cannabinoids, grain and fiber. She offers tips for both novice and advanced hemp farmers.

MASON WALKER

Co-Owner, CEO, East Fork Cultivars

East Fork Cultivars is a 12-acre outdoor craft hemp and adult-use cannabis operation nestled in Southern Oregon. East Fork Cultivars, which now has 13 farming employees, has been in operation for more than five years. Its USDA Organic and Sun+Earth-certified hemp products are grown, dried, cured and later processed and sold for products like CBD beverages, Rogue Ales, Gaia Herbs and more. It also produces its own hemp seed line. Walker provides pointers for CBD-rich hemp flower farmers.

1. Watch out for young plant diseases.

Beckerman says when hemp is young and soil conditions are wet, plants are susceptible to common pseudofungal and fungal diseases such as Pythium, Phytophthora, Rhizoctonia and Fusarium. These are diseases that commonly attack a plant’s roots. “When soil temperatures are cooler, we expect to see more damping off,” meaning increased disease presence, she says.

© Janna Beckerman, Ph.D.

2. Enact strict sanitation protocols.

Sanitation is key to preventing disease from spreading, especially for those cultivating in a greenhouse. Beckerman suggests making sure surfaces are cleaned daily, benches are disinfected on a regular basis and growers use appropriate commercial disinfectant. She adds that if growers are using those products, they end up protecting against bacteria and viruses that affect people as well. She strongly recommends removing infected plants, which “can easily produce hundreds of thousands to several millions of Botrytis spores,” she says.

3. Don’t work with wet plants.

“Any sort of working with plants when they’re wet is a risk. Generally, when you’re scouting, you want it to be dry,” she says, adding that when plants are wet, “it’s an easy way to spread not only bacterial diseases but easily injure the plants and allow entry of other pathogens.”

While uncontrollable for outdoor growers, rain and hail can also pose significant bacterial issues, Beckerman says. Moisture from rain can increase the prevalence of disease, and hail can injure plants when it strikes, allowing the bacteria to make its way into the plants.

4. Beware of hemp viruses.

While white mold (Sclerotinia) and grey mold (Botrytis) should be top-of-mind, growers using clonally propagated plants also need to become familiar with the viruses that are being reported with hemp production, such as Tobacco mosaic virus (TMV) and curly top virus, Beckerman says.

To spot a virus, Beckerman says to look out for any sort of leaf deformation, ring spots, discoloration and browning/wilting.

5. Assemble your scouting tool kit.

When scouting for disease (or pests), it’s important to bring along either a pen/notebook or digital device for documenting, a knife to cut into stems when necessary, a trowel to dig up whole plants to collect samples, brown paper bags for culled plants (Beckerman suggests against plastic because it can encourage mold), and a cellphone or digital camera for photos.

Beckerman says there’s no one right way to store your scouting data; just make sure it can be easily accessible for years to come to understand what’s happened on the farm over time. She encourages always documenting issues with imagery and recording an issue description with the time and location. Beckerman also suggests keeping notes handy with history of the land, including what was planted there previously and how the land was treated (for example, tilled or treated with herbicide.).

© Janna Beckerman, Ph.D.

RAYMOND CLOYD, Ph.D.

6. Employ an aggressive scouting program.

Cloyd suggests scouting two to three times per week as part of a plant protection or integrated pest management (IPM) program. “There are very few, if any, insecticides or miticides labeled for hemp,” he says. “You are basically in the same boat as [THC-rich] cannabis growers. Therefore, it is better to be out aggressively scouting your crops, and if you find any pests, physically remove them from plants.”

© Janna Beckerman, Ph.D.

7. Use a forceful water spray.

One way to remove a pest infestation is to spray the affected plants with water, Cloyd says. “Fill up a 100-gallon sprayer of water, and just go through the crop and forcefully remove or dislodge the insect or mite pests. Do it in the morning so you do not run the risk of any disease problems” due to excess moisture accumulating in the evening when cooler temperatures occur, he says. Cloyd notes that no protective clothing is needed with this method, and water alone will likely have only minimal impact to the chemical composition of cannabinoid-rich hemp plants.

8. Use the ‘beat’ method.

When looking for insect and mite pests, one of the most effective methods is fairly simple: Position a clipboard with a white or black piece of paper underneath the plant canopy and shake a random sampling of leaves or branches over the clipboard, and look for any insect and mites that land on the paper, Cloyd says.

9. Yellow sticky cards can be helpful, but use caution.

Yellow sticky cards are useful for understanding what insect and mite pests are present in a greenhouse; however, Cloyd notes that the use of yellow sticky cards outdoors may be difficult. The cards, he says, will “pick up the adult moths that are larvae (caterpillars) so that will give you a heads-up … that you may see caterpillars soon, and that will help intensify your scouting efforts. But if you put these sticky cards outdoors, you’re going to catch good and bad bugs that can fly.” Yellow sticky cards also won’t capture mites because they do not have wings. Therefore, visual inspections and the beat method are best used in tandem for outdoor grows.

SHELBY ELLISON, Ph.D.

10. Know your chokepoints, and consider your labor early.

“The way that hemp is grown right now for CBD production is very, very labor-intensive,” Ellison says. “It’s moderately intensive to plant, but that [process] is pretty quick.” It’s also intensive to weed, she adds, especially once it reaches a certain height that makes it difficult for a tractor or other mechanical method to do the job, often forcing growers to do it by hand. However, the “ultimate chokepoint is harvest,” Ellison says. “Many grows struggle to find enough of a labor crew to help with harvest … because you’ll have this two-week time frame when you’ll have to get all the plants out of the field.”

MASON WALKER

11. Lean on your certification adviser.

Farmers with certifications such as Sun+Earth or USDA Organic can tap into those certifying bodies for more agriculture tips, Walker says. “They understand organic farming really well, so you get a lot of value from the certifier to understand your options for soil health inputs, fertilizers and pest control because there are a lot of options out there that are not the … approaches that Big Ag relies on.”

12. Delegate your data collection, and cross-train your team.

A CBD-rich farm can produce lots of useful data. To keep those data points centralized and accurate, it’s important to delegate that information gathering to certain team members. At East Fork, one person is in charge of all data regarding their farming methods, another person is in charge of recording their plant trialing data, and another is solely responsible for gathering and evaluating records for compliance with their various certifying and regulatory bodies. On the other hand, he says, it’s important that others in the operation know how the process works in case an employee is unable to perform their duties. “One thing we’re pretty high on as a work culture is cross-training and transparent information sharing,” he says.

Cassie Neiden is the conference programming director for Cannabis Conference, produced by Cannabis Business Times, Cannabis Dispensary and Hemp Grower, and editor of Cannabis Dispensary.

© mates | AdobeStock;

1. Seed and clone quality.

One of the first challenges starts with what growers put in the ground—seeds and clones. Many established farmers have quality expectations based on their successes with other crops. Unfortunately, both hemp seed and clone quality varied widely in 2019, significantly impacting production. At Purdue, we have studied seed quality, and one of the biggest issues is a mismatch between the label and what we see in the bag of seed. Getting seed that is clean and has a high germination percentage has been challenging in this industry. Germination and percent feminization were two big disparities for many growers last year. Clone quality was assessed by overall health when growers received them. Growers reported poor root development and pest infestation as two big clone issues last year. In addition, seeds and clones should match the cultivar name on a certificate of analysis (CoA). The best solution to combat quality issues is to find a reputable provider—easier said than done in this nascent industry. Speaking with other growers can help uncover the bad players, and sometimes, the good players, too. Established indoor facilities are starting to break into clone production, so those of us involved in hemp research at Purdue hope they will provide high-quality plants because they have a reputation to uphold in their communities.

2. Labor and related costs.

Another challenge we saw last year was difficulty in securing labor. Labor challenges are not unique to hemp, but many new growers vastly underestimate the need to hire labor for production. This includes labor for planting, in-season maintenance (scouting for males, weeding and pruning) and harvesting. Many growers also underestimate labor costs in their initial budgets. While more mechanical innovations exist in hemp production now compared to six years ago, the expense of this type of equipment could be a barrier to entry and is why some may choose to opt for a more labor intensive model.

Securing labor before you purchase seeds or clones will prevent scrambling to find help at the last minute and help you avoid budgeting challenges. Some enterprise budget models, which estimate production costs and help establish appropriate pricing, also build in labor costs. Make sure whatever model you use includes these expenses.

You may also want to look for alternative, less labor-intensive production models, such as investing in equipment to produce cannabinoid-rich hemp in a row crop model, or purchasing specialized harvest equipment for a raised bed system. You will have specific expenses for different models, but in the long term, it could be the best option for your operation.

3. Weed, pest and pathogen management.

Growers have faced and will continue to face the challenges associated with managing weeds, pests and pathogens. These can be difficult to manage in any crop, but hemp producers have fewer tools that are tried and true. It seems like every time I step into a hemp field, I find a new pest or disease. The more time we spend in the field looking for problems, the more likely we are to find them, but it can also help find solutions.

If you have little experience in farming, one of the first solutions is to turn to experienced crop producers. Growers who have produced many other crops can pull techniques from their repertoire and apply them to hemp. Organic producers can be invaluable resources for hemp growers because they also have limitations on the products they can use. Referencing scouting articles and university resources can help you understand what you should expect to see in hemp fields. These resources can also help you develop integrated pest management plans for different pests, pathogens and weeds. Growers and researchers alike are investigating solutions for specific problems. The more years of production and research we have under our belts, the more management tools growers will have. Scouting your fields and staying up to date on current research is a great way to become familiar with problems in the field and how researchers are working to find solutions.

© Whitney Cranshaw, Colorado State University, Bugwood.org

4. THC level compliance.

A challenge unique to hemp growers is the compliancy testing for tetrahydrocannabinol (THC). Compliancy testing for THC is nerve-racking for many growers, especially if they planted a new cultivar with limited production data (which makes up a lot of what is on the market today). Failing the state compliancy testing can be economically and emotionally devastating for a grower, and destruction leaves a bad taste in everyone’s mouth.

Researchers have mapped the Cannabis genome, and multiple publications exist on Cannabis genetics and testing techniques. However, even with information to guide breeders and growers, a lot of unreliable genetics are still on the market. One of the solutions goes back to the earlier point of finding a reputable seed or clone provider. Again, I know this can be easier said than done, but this is crucial to avoid bad players and possible crop destruction.

Another solution is to self-monitor during the growing season by testing on your own, which many growers already do. This can be costly if done frequently, so be sure to build testing costs into your budget. This frequent self-monitoring is a smart decision to help determine when to harvest to maximize cannabidiol (CBD), or any other cannabinoid, while still remaining THC-compliant. Eventually, I hope to see all cultivars pass compliancy testing, regardless of when growers decide to harvest.

© rcfotostock | AdobeStock;

Marguerite Bolt is the hemp extension specialist at Purdue University’s Department of Agronomy. She received her M.S. in entomology from Purdue University and her B.S. in entomology from Michigan State University. Bolt’s research has focused on hemp-insect interactions and plant chemistry.

Hemp production takes many forms, and with those various forms comes the need for different irrigation treatments.

The best irrigation systems will differ depending on production practices, where the hemp is grown and what it’s grown for. However, some irrigation principles apply to all hemp growing methods.

The goal of irrigation management should be to provide the plant with an adequate amount of water using the minimum number of applications and without overfilling the root zone. It is important to never wet below the root zone, as this wastes water and can even potentially waste nutrients. Plants need enough water to saturate the top half of the root zone at least once per week, as the nutrients in the soil need water to move into the plant.

For newly planted hemp, this zone may be only a few inches deep. But as plants reach maturity, rooting depth may be 36 inches or more. Growers should also monitor weather forecasts for anticipated precipitation to make the best use of rainfall and adjust irrigation plans as needed.

Choosing a System

While many growing operations have existing irrigation systems, farmers looking to add hemp to their crop rotations often look to integrate watering equipment that is ideal for hemp production.

The most common form of irrigation across the country is a sprinkler system (see Table 1), which includes center-pivot and traveler equipment. These systems are designed for deep-rooted crops (24 to 36 inches) where the roots also extend laterally throughout the soil between plants. Overhead sprinkler systems allow producers to germinate seed or incorporate surface-applied fertilizer.

Hemp production in 36-inch or narrower rows—usually used for fiber and grain production—will have root systems that fully recover overhead-irrigated water, making it an efficient method of irrigation in these situations. The high fixed cost of overhead irrigation, however, results in the need to utilize a crop rotation with other high-value crops, such as vegetables and crops grown for seed production, that can justify expenses in non-hemp production years.

Although hemp can be grown in the same field continuously—assuming the soil is adequate for hemp production in the first place—it would be best to grow it in a rotation to reduce the risk of increasing insect pest pressure and fungal inoculum.

Some hemp production methods present challenges for overhead irrigation. Plant spacing greater than 36 inches apart, which is common in cannabidiol (CBD) production, can increase weed pressure and create areas where overhead irrigation water will pass through the soil without reaching the crop. Plastic mulch can exacerbate the problem by directing overhead irrigated water away from the hemp plant root mass, making irrigation inefficient. In addition, frequent leaf-wetting can make cannabis susceptible to foliar diseases, such as white mold or gray mold, making frequent overhead irrigation applications even more undesirable.

Drip irrigation excels where row and plant spacing are wider than rooting areas. This method allows for water application directly to the root zone. Growers have the flexibility of using thin-walled drip tape with a single-year life span or longer-life drip tubing that can be rolled up and reused for two or more years. Either would allow for a minimal long-term investment. Some of the water supply components, such as the main distribution line and manifold, can be relocated each year to a new field if the hemp is grown in a rotation with other crops. Drip irrigation systems also work well with plastic mulch, providing efficient water application and weed control. Adding fertigation (fertilizing through drip irrigation) allows producers to spoon-feed the plant for efficient water and nutrient delivery.

Foliar diseases are a major factor in irrigation selection for hemp production. With few fungicides registered for hemp disease control (see Table 2), growers need to minimize disease potential by limiting the amount of times they wet the leaves. Drip irrigation eliminates wetting the leaves altogether. When drip irrigation and plastic mulch are used together, the ground surface remains dry, lowering the humidity at the leaf level and further reducing foliar disease potential.

How Much Should I Water?

Knowing how much water to apply is as important as knowing which irrigation system to use. Crops that close to a solid canopy will need more water than crops without closed canopies. Water requirements should be calculated based on canopy cover and sunlight interception rather than on total acreage.

With overhead irrigation, calculate the volume of water applications by adding inches of rainfall plus inches of irrigation that fall into a rain gauge.

If using drip irrigation, growers will need to convert to gallons of application. Drip irrigation tubing and tapes are rated by output per emitter, or per foot of row, in gallons per hour. As an example, a grower with plant rows 220 feet long and a crop canopy 2 feet wide has 440 square feet of canopy cover (220 x 2). This equals roughly 1/100th of an acre of sunlight interception (440 square feet of canopy cover divided by 43,560 square feet in an acre). To calculate what a 1-inch application of water would be on that area, use the formula shown below.

So, using this formula with the example given, a 1-inch application over one row would be equal to 274 gallons.

A single drip tape the length of the row is installed, and the drip tape delivers a half-gallon of water per foot per hour. Almost all crops in the Midwest require approximately one-quarter inch of water per day at the time of peak water need, which usually correlates with the reproductive stage or, for crops that do not reach flowering, peak biomass production. This water requirement is general and is based on water use coefficients that have been developed with numerous crops through research. However, more research needs to be conducted to determine these coefficients for different hemp types.

Instead of providing one-quarter inch of water per day, as is ideal in the Midwest, many farmers prefer to apply 1 inch of water every four days to cut back on frequency of running the system. In this example, the farmer will be applying 110 gallons of water per hour of run time (220-foot-long rows multiplied by the half-gallon of water per foot per hour from the drip tape). So, he will need to run the system for 2.4 hours every fourth day to provide 274 gallons (274 gallons needed divided by 110 gallons per hour), or the equivalent of a 1-inch rainfall in the given area.

Some farmers use checkbook scheduling methods to calculate how much irrigation is needed to make up the deficit between crop water use and rainfall for the previous week. A checkbook method of irrigation scheduling follows the concept that the soil in a field is like a bank checking account. As a starting point, crops will have the rainfall from the week available plus the water stored in the soil. Rainfall and irrigation applications are deposits into the checking account. Daily water removal from evaporation and transpiration from the field and crops are withdrawals from the account. Soil has a maximum amount of water it can hold (called field capacity), so any water added beyond the soil’s water holding capacity would be a loss.

The University of Minnesota has published a checkbook scheduling spreadsheet. While the spreadsheet is meant for growers in Minnesota and North Dakota, it serves as a launching point for anyone who wants to use the checkbook method. The method requires monitoring a crop’s growth, knowing the soil texture in the rooting zone, observing and logging the maximum air temperature each day, and measuring and logging the rainfall or irrigation applied to the field. (To access the spreadsheet and a full manual on how to use it, visit https://extension.umn.edu/irrigation/irrigation-scheduling-checkbook-method.)

No matter what growth stage they’re in, crops need more water when rainfall frequency and volume decrease. Matching hemp’s water needs with the appropriate type of irrigation system and amount of water applied is essential to producing a successful crop.

Lyndon Kelley is an irrigation educator with Purdue and Michigan State University (MSU) Extension.

Eric Anderson is a field crops educator with MSU Extension. Additional information about hemp and irrigation can be found at www.canr.msu.edu/hemp and www.canr.msu.edu/irrigation.

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

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.