New, fall-seeded hemp varieties could revolutionize the way the crop is grown in Canada, according to bio-prospector and hemp breeder John Baker.
Most traditional hemp varieties grown for grain and fibre cannot survive the winter under the soil, which means that it must be planted in spring. Then the crop is vulnerable to shading from aggressive weeds during the critical first month.
But new germ plasm that Baker discovered growing wild in remote areas of Ontario could change that.
He believes that the feral varieties, which have developed the winter seed dormancy trait common to many wild plants, are the descendants of Russian hemp varieties introduced by the British navy before the War of 1812.
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In an ironic twist, archival research found that the original seedstock was distributed by the county sheriffs, who browbeat reluctant local farmers into growing the crop in the service of the Empire, which needed rope and sail-making materials.
The winter dormancy trait was acquired possibly by mutation and passed on to subsequent generations that have survived to the present day.
Since Baker began breeding hemp eight years ago, he has found more than 20 isolated and unique feral hemp varieties with THC levels well below the legal limit.
Describing the process as similar to breeding corn, the president of Stonehedge Bio-Resources in Stirling, Ont., is developing new hybrids based on what he has named Upper Canada Heritage Hemp genetics.
Of the total, he has maintained eight, with two now in serious development stages.
“So we have a whole group of genetic material now that has this overwintering trait. Not as a plant, but as a seed in the ground,” said Baker. “They are extremely well adapted to our region. They wouldn’t still be around unless they were.”
The potential for biomass yield with the new hemp varieties is staggering, he said.
Spring-seeded Petera, a registered variety being tested, yields four tonnes per acre. Tests have shown that Petera can be successfully fall-seeded, and could top about seven tonnes an acre with the early start, he added.
“The potential is huge. It’s going to drastically change the economics of growing this crop,” said Baker.
Other competing crops such as switchgrass or Miscanthus giganteus may compete with hemp’s biomass potential in warmer, more southern climes, he said, but not under Canadian conditions.
“I think it has the potential to be an amazing biomass crop all the way from B.C. to Newfoundland,” said Baker.
Inputs for biomass hemp are similar to those for soybeans, he said, with 100 lb. of nitrogen per acre sufficient under good soil conditions.
“If you put it on garbage land, you’ll get garbage yield. If you put it on exceptional land, you’ll get exceptional yields.”
Cold required
The new varieties offer relatively lackluster results if spring seeded because they require a cold period to break dormancy.
Fall seeding mimics conditions in the wild and capitalizes on the plant’s ability to grow at such a rate that no prairie weed stands a chance, he added.
“It’s up and out of the ground before anything else.”
Perennially cropping the new strains of hemp offers an intriguing possibility, said Baker, but management practices must address the problem of overcrowding.
“If you just let it volunteer, like it would in a barnyard, often it will get too thick and doesn’t do as well,” he said, adding that one-pass discing or harrowing the crop in spring might suffice.
