WYOMING, Ill. — Farmers growing industrial hemp in Illinois can choose to focus on growing the crop for fiber, grain or cannabidiol.
“We have a long history of growing hemp in Illinois for the World War II effort,” said Phillip Alberti, University of Illinois Extension educator, commercial agriculture. “We had 11 hemp mills processing fiber across Illinois.”
This history shows that the crop can be grown in Illinois, however, Alberti said. that was 70 years ago. “The varieties have changed and the climate has changed and because of that we have a lot of work to do,” he stated during a presentation at the Introduction to Industrial Hemp Workshop.
There are male and female hemp plants and it is an open pollinated crop. “Hemp is photoperiod dependent so the earlier you plant the crop, the more biomass you will get,” he said. “From 10 to 12 hours of darkness is the trigger for flowering. The varieties we’re using are coming from Colorado, Oregon, Canada and Europe, so their photoperiods are different than ours.”
Hemp likes to grow in well-drained soils. “For field selection, choose fields that are highly productive with low weed pressure and well drained,” Alberti said. “The crop has very slow growth in the first month and then it takes off so you have to keep it weed free for a month.”
There are no registered herbicides or insecticides for industrial hemp. “Use of cultivation and preparing the seed bed is critical to get good weed control,” he added.
Nutrient demands of the hemp plants increase as the crop grows. “Nitrogen is critical for getting the crop started and for vegetative growth and phosphorus is important for seed establishment,” Alberti said. “Potassium and sulfur are very important for standability to increase cell wall strength and reduce susceptibility to logging.”
The insects that may impact hemp crops include European corn borers, Japanese beetles, and grasshoppers. “Spider mites, aphids and whiteflies are primarily greenhouse issues,” Alberti stated. “We are also watching for white mold and gray mold.”
Planting seeds for grain hemp can be done by broadcast, a grain drill or a corn planter with modified seed meters. “Planting rate is 25 to 35 pounds per acre and you harvest the crop with a combine,” Alberti said. “You only chop the top third of the plant and then you can go back and harvest the rest of the plant for fiber.”
Since hemp is an oilseed, the grain must be put into aeration bins immediately after harvest. “If you don’t store the grain properly, it will spoil and that happens fast,” Alberti noted. “Like canola, you harvest the hemp grain when the seeds are 70 to 80 percent mature.”
Hemp seed oil is different from CBD. “Hemp seed oil comes from processed seeds not processed flowers,” the speaker said. “It has potential for human and animal feed.”
A grain drill or broadcasting can be used to plant seeds for fiber hemp. “You will double the planting rate at 50 to 70 pounds per acre because you want the plant to be very tall and thin which makes the hemp fiber easier to process,” Alberti stated. “When the stalks are thicker they are harder to decorticate or process.”
The hemp fiber or hurd is used in building materials and paper. “Dust pellets are used as absorbents or burned as biofuel so the entire hemp plant can be used,” he said.
Planting stock for CBD is typically done with transplants and a transplanter. Farmers also can plant them by hand with spacing of three to five feet between plants. “You will have from 1,000 to 2,000 plants per acre and the plants are harvested by hand and hung to dry in sheds,” Alberti said.
“CBD is found in the floral material of unpollinated plants so the male plants must be culled,” Alberti said. “CBD production is labor intensive and currently there are no hemp grain or fiber processors in Illinois.”
There are several ways to do CBD extraction. “Each method has its pros and cons depending on the end product,” he said. “Hemp-derived CBD is available in many forms and concentrations so how it is processed will determine that.”