Gerald Almy: Sunn hemp a new food plot option

Gerald Almy

Gerald Almy

For summer food plots for wildlife, you can’t go wrong with soybeans. And what the deer don’t eat, you can sell as a valuable cash agricultural crop when the beans ripen.

In this column we’re going to examine a newer offering for food plots — sunn hemp. Well, the plant itself is not actually new. It’s been around for many years, originating in India around 600 B.C. But it is so new for use in food plots that comparatively few deer managers know much about it or have tried it. I have to admit this is the first year I have planted this crop, but extensive research shows it should be a great seed to put in the ground for wildlife and also as a soil builder and rejuvenator.

According to the United States Department of Agriculture (USDA), sunn hemp has been tested in the U.S. since the 1930s and has shown extensive benefits for soil. It also grows well as a cover crop on poorer soils than many other plants.

It is used extensively in many countries, especially Brazil, as a soil improvement and green manure crop because of its ability to produce large amounts of biomass in as little as 60 days. “Because of this, it has the potential to build organic matter levels and sequester carbon,” the USDA says. “Also, as a legume it can fix large amounts of nitrogen. Used as a cover crop, sunn hemp can improve soil properties, reduce erosion, conserve soil water, and recycle plant nutrients.” They add that it is also resistant to root-knot and nematodes, and may ultimately prove useful as a biofuel crop.

The ability to restore nutrients to the soil makes sunn hemp especially appealing, and it’s a great crop to plant in summer to add nitrogen before a fall planting of wheat or oats, which can then utilize that nitrogen. It’s been shown to produce up to 134-147 pounds of nitrogen per acre after just 60 days. Even if a winter crop isn’t grown, a large portion of this nitrogen will remain for agricultural corn planting in spring.

Sunn hemp also brings up to the topsoil from the subsoil 10 pounds of residual phosphorous and up to 80 pounds of potash per acre, while creating four tons of organic matter. In extremely favorable conditions it can release up to 200 pounds of nitrogen, 160 pounds of potash, and 20 pounds of phosphorous.

Sunn hemp can be planted any time after frost danger is gone, but grows best when the soil temperature is 65 degrees or higher. The first heavy frost will kill it in fall, much like soybeans.

Sunn hemp grows quickly. It can reach 4-6 feet tall in just 60 days. What’s more, it’s resistant to heavy early browsing by deer and will keep growing back. In fact, sunn hemp grows so fast that it’s recommended that it be cut back to about 12-14 inches height after it reaches six feet because the stem can become chewy and fibrous. The new tender leaves that emerge will be more appealing to deer. Left uncut, it can reach 10-11 feet!

As you can imagine, this makes sunn hemp very appealing to deer for cover as well as food. Some animals will simply bed down in it and get up to eat during the summer. It’s also great cover for quail, if you’re fortunate enough to have any of those delightful gamebirds in your area, providing cover and lots of insects for the birds to feed on. For agricultural purposes, goats also do well on sunn hemp.

Sunn hemp costs anywhere from $2-6 per pound, depending on the quantity you buy. I’ve seen seeding rates vary in recommendations from 15-40 pounds per acre, so this is not an inexpensive plant, but it is not prohibitively costly, either, at least for a few plots to experiment with and improve the soil. And when you consider that its protein level is 30 percent, its benefits to deer should be outstanding. Since it grows so thick, it is also a tremendous weed suppressor and eradicator.

Plant sunn hemp by drilling or broadcasting and cover ¼-1 inch deep. It does best on well-drained soils, rather than wet areas. The pH does not have to be high. Over 5.5 is fine.

This plant is excellent for mixing with other crops such as soybeans, lablab and cowpeas. It will divert some early browsing pressure from deer, allowing them establish well, and also provide stalks that these plants can “climb” as they grow, providing increased yield. You can also mix it with sunflowers, sorghum or corn. If you plan it later in summer, mix it with cover radish crops which will thrive after the sunn hemp dies following heavy frosts.

This is an exciting “new” food plot seed that wildlife managers and farmers may want to experiment with more extensively. It is sold by several sources that you can locate with an internet search. Several I’ve checked out include Hancock Seed Company, Tecomate, Turner Seeds, and Petcher Seeds. Expect many more wildlife food plot seed companies to be jumping on the bandwagon and offering straight sunn hemp or this intriguing legume mixed with other food plot seeds in coming years.

And I’ll keep you posted on how my experimental plantings go!

Award-winning outdoors writer Gerald Almy is a Maurertown resident.

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