Cover crops are plants that are grown to help the soil on a small farm--whether that's improving its structure, adding nitrogen, conserving moisture, preventing erosion, suppressing weeds, or even helping other crops by boosting disease and pest resistance. Sudan grass is one of these crops.
There are many cover crops to choose from, and your farm will benefit if you choose the one that meets your needs in a particular place at a specific time and that works with your climate.
What is Sudan Grass?
Sudan grass is a fast-growing cover crop with an extensive root system that thrives in the heat of summer. It excels at suppressing weeds.
Its funny name comes from the fact that it is a hybrid, a cross between sorghums grown for forage and a type of grass called sudan grass or sudangrass.
It's easily grown most places in the United States (soil temperature must reach 65°F to 70°F for two months before frost) and it is extremely drought-tolerant once established (it does need rain or irrigation in early growth).
Tips for Planting Sudan Grass
Seed Sorghum Sudan grass at a rate of 40 to 50 pounds per acre if broadcast, 35 pounds per acre if drilled. Plant after frost threat has passed in spring, but before July 15 in the Northeast for maximum growth potential.
Soil temperatures of at least 60°F are required for this cover crop to germinate. Repeated mowing can increase the root system, leading to greater penetration in compacted soil. In fact, this cover crop should be mowed several times in the season to prevent it from setting seed.
Why Grow Sorghum Sudan Grass?
Sorghum Sudan grass is the best at revitalizing worn-out, "farmed-out" soils, adding a lot of organic matter and bulk to the soil.
It grows so quickly, especially in temperate regions, that it creates a thick stand that cannot be penetrated by weeds. It's also very tolerant of heat and drought, making it hardy. And the first frost will kill it - so it's great to leave over winter as a dead residue to protect from soil erosion. Sorghum Sudan grass is also excellent at penetrating compacted subsoil and improving the structure of the soil. It's often recommended to follow Sorghum Sudan grass with a legume cover crop, such as clover, to restore soil health.
It will add a lot of biomass to the soil, partly because it grows so tall--five to 12 feet--with stalks up to a half-inch thick.
Finally, it's an excellent quick forage for pastured animals.
As mentioned above, maintain by mowing several times during the season before the crop seeds. Just prior to a killing frost, mow the Sudan grass to finely chop it and then immediately till into the ground while still green. Due to the presence of weed-suppressing compounds in the freshly mowed crop, wait several weeks before planting crops.