As a hemp farmer, you’re likely well into your growing season by this point. With prep and planting out of the way, farmers’ focus throughout most regions has by now shifted to disease prevention, labor and training, as well as preparing for harvest.
In this special three-part series, Hemp Grower spoke with cannabidiol (CBD), grain and fiber farmers, as well as university researchers at the top of their fields, to gather reliable, actionable tips you can implement throughout the growing season.
In this issue, Part II will focus on some mid-season considerations and challenges, including pests, diseases and more.
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.
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.
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.).
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.”
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.
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.”
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.