Hemp can germinate in soils between 40-50°F, and with the warm temperatures in late march, volunteer and feral hemp (ditch weed) had the right conditions to pop up. Feral hemp was observed on March 29th in Jasper county (thanks Bryan Overstreet). However, the recent cold temperatures did cause some damage. 2019 hemp growers should be on the lookout for volunteers if they grew for seed/grain or harvested their fiber hemp after seed set. From an insect pest management perspective, volunteer hemp can be a food source for pests early in the season, like Cannabis aphid. Cannabis aphid overwinter as eggs in the field, so volunteer plants provide an early season meal.
If you are planting hemp in the same field as last year, your site should already be licensed for 2020. However, if you are going to plant a different crop in that 2019 hemp site, be sure to terminate volunteers. Hemp is pretty wimpy early in the season and can be terminated through tillage. Historically, feral hemp has been controlled by county weed boards with herbicide applications. Volunteers are likely to perish during a burn down targeted at broadleaf weeds.
Feral hemp found on March 29th, 2020 in Jasper County. (Photo Credit: Bryan Overstreet)
Feral hemp with frost damage.
