The growing world of industrial hemp

SIU weed scientist Karla Gage offered some basic beginning information about industrial hemp during a field day at Southern Illinois University’s Belleville Research Center in St. Clair County.

CARBONDALE, Ill. — Think growing industrial hemp is as easy as growing corn or soybeans? Think again, warns Southern Illinois University weed scientist Karla Gage.

She’s been alerting farmers around the state about industrial hemp’s unusual plant characteristics, growing and harvesting needs and product uses during field days this summer. One of them was at the SIU Belleville Research Center’s annual field day in St. Clair County. Her comments were geared toward industrial hemp, not CBD-oil generating hemp.

Here’s what she had to say:

Not pot — She stressed that the cannabis species grown as industrial hemp has less than 0.3% THC. In other words, this plants does not possess any — zero — psychoactive properties as marijuana. “So with that amount of THC, you can smoke it all day, it’s not going to do anything to you. So we’re not growing marijuana here, we’re not growing pot, we’re growing industrial hemp.”

Permits required — To ensure that no growers try to grow marijuana illegally, all Illinois industrial hemp growers must be permitted through the Illinois Department of Agriculture. What’s more, the ag department also requires lab testing for THC levels on a regular basis.

Four- or five-crop rotation — As a weed scientist interested in sustainable weed control, Gage also studies crop rotation, its impact on the weed competition and solutions to weed herbicide resistance. She suggests that southern Illinois farmers consider adding industrial hemp into their commercial crop rotation with corn, soybeans, wheat and/or sorghum.

“If you could add industrial hemp into (a rotation), even a three-crop rotation is going to improve things over what we have now. But we have a long way to go to make this profitable,” she said.

Gage noted it will take a few years for hemp processors to ensure they have infrastructure in place to receive the crop.

“There’s an already pretty solid infrastructure in Kentucky for fiber production. So that’s a model a good model for us to follow,” she said, “Ideally, more crops in rotation it would be a good idea.”

She also pointed out a recent article stating that “this crop was highly competitive against the weeds,” and to see if this holds true in southern Illinois, SIU is launching research to study the competitive effects between water hemp and industrial hemp.”

“We want to see if this truly is a crop that can suppress our weeds,” Gage said. “We know that we have to get the crop established early, it has to close canopy in order to suppress those weeds, where you want to see it in rotation with other crops, we want to look at the control of volunteer hemp.”

First research plot — SIU researchers have planted the first industrial hemp plots at the Belleville center. Most of the studies are currently focusing on production best practices. Those plots were planted with seed at about a half inch deep to help with germination. Yet, like much of Illinois, rain issues created planting issues.

An Illinois weed — Gage noted that industrial hemp is a known entity in Illinois as a weed, with some calling it ditch weed. “And that’s another source actually for genetics. They’re potentially pretty valuable. So if you know somebody with ditch weed, you might want to give them a heads up and send them to me,” she said.

Researchers will be combing all sources, including European industrial hemp, for the best genetics for an ideal southern Illinois variety.

Besides looking at the feasibility and desirability of production, Gage said research will look at the required soils and growing conditions, the seed availability and varieties, the harvest methods, the markets, and the environmental benefits.

Agricultural costs — Citing that there are as many as 30,000 products that can be made from industrial hemp, Gage said the uses ranges from food, personal care products, consumer textiles and then industrial applications such as inks.

“So, these economic figures are a moving target changing all the time,” she said, adding that it’s estimated about $21,000 per acre for seeds, $12,500 an acre for fiber and CBD production from $10,000 to $75,000 an acre.

Planting systems — Decisions on how to plant hemp depends on the end product.

Hemp for hemp requires a variety that’s really tall, but doesn’t have a lot of branching, Gage said. “When it matures, the stalks at the base are going to be void of leaves. You’re going to harvest that when it’s about the diameter of a pencil. When it’s planted densely, it’s going to be the most competitive with our weeds,” she said.

When planting for dual purpose of harvesting seeds and fiber, “that’s where you harvest the seeds off the top of the plant, and you can come back later and harvest the stems for fiber. If you’re going to do that, though, you need to identify your fiber processor first,” she said.

There’s also planting for an oil seed which needs a low-density planting to accommodate shorter plants and will not compete well against weeds.

Agronomic basics — For row crop production, Gage said there’s safe germination within seven days, it’s going to be sensitive to drought, but also flooding. It should be planted after a danger of hard frost, but some cultivars may be resistant. While optimal germination is 75 degrees, but there’s a wild range between 32 and 113 degrees.

Planting depth is less than an inch, but not too deep, even though it’s a big seed. It’s subject to wind lodging, but when you plant high densities that’s going to help with lodging.

Soil and climate requirements are going to be similar to a high productivity corn and should not be grown on marginal lands.

Harvesting fibers is a slow process, at about 1.5 to 5 acres per hour. Be warned that the fibers will wrap around every moving part of the combine. “One of the common recommendations is to make sure your equipment insurance is up to date before you start harvesting,” Gage stressed.

For large plants, specialized equipment such as a three-tiered sickle bar mower is going to help prevent the fibers from wrapping.

Short history — Gage said there isn’t a good economic history yet with industrial hemp because of its short legal production period so far.

So, the economics are just all over the board. “You know, I hear it called the ‘Wild West’ all the time. Because there are a lot of people out there who are promising things and they’re not delivering. Some people are trying to get rich, quick,” Gage said.

What this means is “in some cases you don’t know who to trust.”

This makes research all the more important and also prompts growers to learn as much possible to make informed decisions.

Gage can be reached at

Karen Binder can be reached at or 618-534-0614. Follow her on Twitter: @AgNews_Binder.


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