Putting hemp in your rotation?

Still looking for a new crop for the 2020 growing season? It might be time to take a new look at hemp

With lighter regulations and more agronomic information available, is this the year to grow hemp on your farm?

Adding hemp to your crop rotation doesn’t involve as many regulatory hoops as it used to. With shorter varieties that make residue management easier and rapidly growing markets, especially for organic hemp, there seems to be a lot of potential value in this specialty crop.

Most hemp grown in Western Canada is used for human consumption, although there is renewed interest in hemp fibre, and if a planned decortication plant in Alberta goes ahead, it could provide future opportunities for the straw by-product.

For growers planning to sell hemp to the food market, there are a few agronomic and production considerations. Scott Wolfe, agronomist with Manitoba Harvest Hemp Foods, spends a lot of time with new and experienced contracted growers, helping them fit hemp into their rotations. Take these nine tips into account if you’re thinking about getting involved in the hemp industry this year.

1. Find the right field

“We like to avoid canola and other oilseeds right before hemp just to avoid sclerotinia and some diseases like that,” says Wolfe. Growers considering growing hemp specifically for a gluten-free or allergen-free facility like Manitoba Harvest Hemp Foods need to know that crops like soy and mustard are considered allergens. “Wheat, barley and rye all have gluten-containing agents, so rotations can get a little limited,” Wolfe says, “but we work with whatever growers have.”

As with any other crop, it’s not a good idea to grow hemp on hemp, and a longer rotation is better, but Wolfe suggests that if growers have a cereal in their rotation they make sure to follow it with a legume or pulse crop to break up disease and pest cycles. “Canola, with its prevalent acres on the Prairies, can increase incidence of sclerotinia in a field, so we try and rotate as far away from it as possible,” says Wolfe. “A cereal helps break up the disease cycle as sclerotinia is a generalist disease on broadleaf plants. Legumes can still be infected by sclerotinia but don’t canopy as aggressively as canola and are generally on wider spacing, so it doesn’t seem to harbour the disease as much.”

Hemp works well for organic growers, who often plant it after a green manure plow-down crop. “Hemp responds well to the high fertility in that situation,” says Wolfe. “Oat stubble works well too because it’s not a gluten-containing agent, and it removes well in the cleaning process. Anything legumebased like alfalfa, or even soybean, even though it is an allergen, the seed size is different enough that it cleans out well, and you also get a nitrogen credit.”

If farmers can seed and harvest wheat and canola, they can harvest hemp, says Scott Wolfe, agronomist with Manitoba Harvest Hemp Foods. photo: Marcus Isaac

One of Wolfe’s growers is seeding hemp on potato ground, to make use of the residual nutrients that the potato crop doesn’t use. “They are working it so much, they get a ton of mineralization the next year, so hemp can take advantage of that,” says Wolfe.

Field selection is important when growing hemp, especially avoiding cereal stubble and fields with wild buckwheat issues, because it’s hard to clean either of these crops out of hemp.

“Because hemp can be so competitive, any volunteer wheat kernels might not mature or fill out as well, so the seeds are smaller and shrivelled and take on the characteristics of hemp seeds in size and shape,” says Wolfe. “Wild buckwheat and immature wheat are very difficult to clean out.”

If hemp fields do have wild buckwheat it’s not the end of the world, but the cleanout costs will probably be higher, says Wolfe, who adds choosing a different variety can help.

“If you know you’re dealing with a field that has wild buckwheat problems, we suggest choosing a different variety,” says Wolfe. “Hemp seed size can vary wildly, so one of the varieties has a 1,000-kernel seed weight of about 13 and on the bigger side, it’s around 21. So, if you have buckwheat problems, plant something with a bigger seed size to minimize your cleanout. A taller variety might shade it out a little better too.”

Hemp doesn’t like heavy clay soils or wet feet, so growers need to choose lighter soils and fields with good drainage. “If you get rain and the water sits there for a couple of days, hemp doesn’t like that and it will stall out, then the weeds take over and you’ve got a bad situation on your hands,” says Wolfe.

Manitoba Hemp Harvest Foods doesn’t allow any in-crop spray applications or any pre-harvest desiccation, although there are not currently any herbicides registered for in-crop control of weeds in hemp. “That ties into setting yourself up for success early on,” says Wolfe. “We suggest our growers manage the field beforehand, whether that’s with a light harrowing or a pre-seed burn-off to take care of weeds before they plant, and give the hemp the head start that it needs to get to a competitive stage.”

Hemp following soybeans is ideal, says Wolfe, because the fields are usually clean and the soybeans leave behind a nitrogen credit that the hemp can use.

2. Choose a good variety

There are 52 approved hemp cultivars in Canada and Wolfe expects that number to keep climbing rapidly with renewed interest in improved yields and the growth potential in the cannabinoid and fibre markets in years ahead.

Manitoba Hemp Harvest Foods sells three varieties of seed. Finola is currently the widest-grown variety on the Prairies mainly because of its harvestability. Because it is auto-flowering, it has a set number of days before it flowers. In some other varieties, flowering is triggered by shortened day length. That means Finola is more predictable in terms of maturity and harvest.

“I definitely recommend it for first-time growers, because the fibre isn’t as strong as other varieties so you can chop it a little better. It goes through the combine a little easier, and they can delay planting to control height expression,” says Wolfe. “We’ve seen growers plant it as early as the second week in May and we’ve seen it reseeded as late as July 1. Obviously, yields are not comparable, but they’re still pulling off a crop. It’s still making them money.”

Some organic growers prefer varieties that grow a bit taller, so something like CanMa, a dual-purpose variety may be a better fit for them. “Dual-purpose varieties can be used for fibre or seed production, but it won’t be like other fibre varieties that can get like 14 feet tall,” says Wolfe. “Basically, it just gives organic growers a little more weed competition if they want that extra foot or two on the plants to shade things out, and it can handle wet soils better than Finola, which is still the best option for reseeding or late planting because it’ll mature much quicker.”

3. Fertilize the crop

A popular myth about hemp is that it doesn’t need a lot of feeding, but although it is highly mycorrhizal and able to scavenge nutrients from the soil, growers should not skimp on fertilizer if they want to achieve the highest yield potential.

“It can loosen phosphorus that may not show up on soil tests, but growers may need to up the phosphorus a bit,” says Wolfe. “It’s a big plant, and needs nutrients to maintain that, so it responds really well to manure and nitrogen.” For conventional growers, Wolfe recommends using as much fertilizer as they would use for canola or a high-protein wheat crop.

Organic growers like hemp because it responds well to manure or green manure crops and helps reduce any issues with nutrient loss from their fields. “For many of our organic growers, their yields rival if not exceed conventional hemp crops,” says Wolfe. “If you can upload it with a green manure or animal manure, it responds really well. And because it roots so aggressively, it can keep taking it up so you’re not losing it; it’s mitigating that leaching mechanism that can sometimes happen. It’s a really good candidate for manure.”

4. Consider your management system

Hemp has a fit with just about any system. It’s another crop to lengthen out a rotation, and, as long as it gets off to a good start, it’s highly competitive, so it can offer good weed suppression. There is, however, a misconception that because hemp grows aggressively and is so competitive, it’s a crop that you can simply seed and leave to its own devices.

“You still want to manage it early on,” says Wolfe. “Obviously no seedling is very competitive, but with young plants, if the weeds get away at that stage, the hemp might not push through, so you do have to manage it early on just to make sure you’re starting with a nice clean field, everything is going well and you give it a good head start.” Once hemp begins elongating it can grow six inches to a foot in a week.

Hemp is also a good fit for growers who are using regenerative agriculture practices like cover crops, intercropping, and planned grazing, and are focusing on building soil health. “One of the pillars of regenerative agriculture is diversity and that’s where hemp can come in,” says Wolfe.

Statistics Canada reported 91,100 seeded acres of hemp in 2019, more than double the 41,200 acres reported in 2018. photo: Marcus Isaac

Hemp sequesters a lot of carbon to help build soil organic matter. “Hemp has a large amount of biomass, so it’s sequestering and building carbon in the soil,” says Wolfe. “If you’re not baling off the straw, you can chop it and work it in.”

Hemp is good at scavenging nutrients from deep in the soil profile and improving soil structure. “Hemp has an aggressive rooting nature,” says Wolfe. “It’s similar to canola in that it has a plastic growing habit, so if you give it space, the plant will bush out. If you plant it really tight, it’ll go monopodial, and have one stem. The roots do the same and will adapt. If a root has plenty of room it’ll spread out and be more fibrous, and if it’s not got a lot of space, it can tap down. Some of those feeder roots can get as low as six feet and pull up some of the nutrients that other plants can’t.”

That allows growers to use hemp in specific places and situations depending on which soil health goals they want to achieve.

“When the crop is breaking down, similar to how a forage radish does, it creates channels that improve soil tilth because the roots of other crops can follow that path, and water infiltration follows that path, so any aggressive rooter that can pull up nutrients that other plants can’t and improve soil tilth is a huge asset,” says Wolfe.

5. Store it carefully

Growers often don’t swath hemp, so it can tend to come off tough at about 16 per cent moisture. The crop needs to be stored below nine per cent moisture.

“Eight per cent moisture is ideal for long-term storage, so you want to get it on air within four hours of harvest, or ideally right away,” says Wolfe. “If you can use supplemental heat or a grain dryer at low temperature, that’s a good idea just to dry it down and make sure you don’t get spoilage in the bin. If you get hot spots, you can get overheating and then we will see rancidity problems.”

If hemp is swathed, it’s usually a lot drier coming off, but then growers may have issues with things like E. coli on the seed if it’s in contact with the soil for any period of time.

“Hemp is a raw food product, so we have to be a little more careful when we talk microbiology,” says Wolfe. Seed is tested to check for potentially harmful bacteria or other micro-organisms at the field level, after it is cleaned and again when it enters the Manitoba Hemp Harvest facility.

In the future, Manitoba Hemp Harvest may be less concerned about bacteria and micro-organisms, as it has just added a pasteurization process at the facility to treat hemp seed. “We still want to encourage correct practices to not contaminate the seed, but we now have a five-kill step so we’ll be able to take microbiology down by shaving five zeros off any numbers that we are seeing that look alarming,” says Wolfe. “For the peace of mind for our consumers, and our buyers it’s a big thing for us and the industry as well, because it takes so much risk out of growing hemp.

6. Get licensed

In 2018, Health Canada lightened its regulations — growers no longer require a criminal record check to be issued a licence to grow hemp, and they can now collect the leaves and fibres as well as the seeds. That change drove a huge interest in growing hemp, which resulted in a flood of requests for licences, so much so that there was a processing backlog. Now, growers can apply online. Licences, which are free, no longer must be renewed every year.

7. Assess demand

The food market for hemp seed has driven the hemp industry up to this point and will continue to do so. Now, CBD extractors are popping up. These companies extract CBD (cannabidiol oil) from hemp chaff. With a decortication facility coming to Alberta, growers will have marketing options for hemp seed, chaff and straw.

8. Do the math

Yields vary by year, soil type and production systems, but Wolfe says a grower who has some experience growing hemp can average around 1,000 lbs./acre, and conventional hemp seed averages around 55 cents per pound. Organic producers may get slightly lower yields, but can command up to triple the price.

“Last year, we were a little bit more conventional than organic. This year, we’re probably about 50/50 and next year we expect to be far more organic than conventional,” says Wolfe. “It’s what the consumer wants, but it also works for the grower, so hemp can work out pretty nicely for organic and conventional growers.”

9. Research special equipment

If farmers can seed and harvest wheat and canola, they can harvest hemp, says Wolfe. Special equipment is not necessarily needed to seed or harvest most of the new, grain-specific varieties of hemp, although some growers do find it necessary to make modifications to their harvesting equipment.

“When seeding we recommend using canola settings because it is a little sensitive seed, and it can crack. Turn the fan speed down so it’s not hitting hidden manifolds and cracking before it gets in the ground, which could affect germination,” Wolfe says.

With a shorter variety like Finola, growers can use most combines without any modifications. “Delaying planting and using Finola ensures an easier harvest. I would recommend that to growers who are new to the crop,” says Wolfe.

If the crop is dry, there can be issues swathing taller varieties; fibre gets stronger as it dries. “So, if growers straight cut and the fibre is fairly green, it can go through pretty well. They can chop it with the chopper and spread it out the back like they would wheat or canola. You do need maybe a little more aggressive knives or newer knives, and make sure they’re sharp.” Some growers have installed after-market Redekopp choppers.

Twin rotary combines are not ideal, though. “More moving parts are generally bad for hemp because they can wrap,” says Wolfe. It’s generally a good idea, with any hemp crop, for growers to carry a few extra pieces of equipment like a fire extinguisher and a leaf blower or air compressor to blow chaff off exhaust manifolds and other areas of the combine where it might pile up. “If they are growing taller varieties it’s about experimenting, and with experience, they will see where wrapping occurs.”

About the author


Angela Lovell

Angela Lovell is a freelance writer based in Manitou, Manitoba. Visit her website at http://alovell.ca or follow her on Twitter @angelalovell10.



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