Home & Garden Garden How to Grow Sorghum-Sudan Grass as a Cover Crop Improve your soil and even get rid of weeds with this popular hybrid plant. By Stacy Tornio Writer University of Wisconsin-Milwaukee University of Oklahoma Tornio has authored more than 15 books about nature, gardening, and getting kids outside. our editorial process Stacy Tornio Updated May 22, 2021 Don Farrall / Getty Images Share Twitter Pinterest Email Garden Urban Farms Planting Guides Indoor Gardening Insects Planting a cover crop like sorghum-sudangrass, a hybrid of the sorghum and sudangrass plants, is a natural way to improve your soil. Cover crops are commonly grown to address poor or nutrient-depleted soil in a specific area. Before growing new plants that gardeners intend to harvest, they may grow a cover crop first to help get weak soil back to a healthy state. If you’ve had your soil tested or know that it needs improvement, this can be a really effective and inexpensive solution. Farmers use this technique all the time, and it can work just as well in backyard gardens. Sorghum-sudangrass, in particular, produces high amounts of organic matter at the low seed costs, making it ideal to put down for renewing soil quality. A single season of growing sorghum-sudangrass is sometimes all it takes to create a new, healthier garden area. Since seeds are inexpensive, readily available, and easy to grow, this is a great option for home-gardening beginners looking for a cover crop. How to Plant Sorghum Sudangrass Growing as tall as 8 to 12 feet, this plant looks a bit like a corn stalk, and its season is similar to those of most other plants and crops. Below are the best tips for getting started. Growing From Seed Growing sorghum-sudangrass from seed is the recommended way to start. Sow seeds directly in the soil after all threats of frost have passed; warm temperatures are needed for the soil to germinate. Water thoroughly after planting. One of the benefits of sorghum-sudangrass is that the seeds are fairly inexpensive, so make sure to overseed the area where you want it to grow; you can trim back the area later on. Growing From a Starter or Plants It will be difficult to find sorghum-sudangrass plants at your local garden center or home store. However, you can start seeds indoors several weeks before you plan to plant. In fact, this approach works so well because the seeds need warm soil to germinate. Starting sorghum-sudangrass indoors will help you get a jump start on creating a great cover crop and getting nutrients back for your soil. When the time is right, plant directly in the ground. Sorghum-Sudangrass Care Sorghum-sudangrass is incredibly low maintenance. It can tolerate strong heat and doesn’t require a lot of water—plus, it goes right to work for you in improving your soil. Still, some basic care tips can help ensure a successful growing season. Light, Soil, and Nutrients Grow sorghum-sudangrass in full sun, just as you would for other crops like corn. As for the soil, you don’t have to worry about adding a lot of fertilizer — after all, you’re planting this cover crop to double as a fertilizer — but you can add organic matter on top to help with overall growth. You could also grow it as a companion crop with legumes; together, they’ll really maximize the added nutrients. Water, Temperature, and Humidity Water thoroughly after the first planting. After that, sorghum-sudangrass can withstand heat and even some mild drought pretty well. This plant thrives in hot, humid conditions. Maintenance While they can grow several feet tall, sorghum-sudangrass stalks should be mowed when they reach 20 to 30 inches, leaving about 6 inches behind. If your garden is a small growing area, just set your mower on the highest level. This usually happens around mid-summer. Then, let them keep growing. At the end of the summer, mow and till completely in the soil. This plant can naturally suppress aggressive weeds that you might be struggling with. Since weeds can play a big part in depleting nutrients, it allows you to tackle two problems at once. In addition, sorghum-sudangrass has an extensive root system, meaning it can "air out" your soil—another way it makes room for nutrients. Packed With Protein Plants, just like people, need good and regular sources of protein. Sorghum-sudangrass has about as much protein as alfalfa. When you put this into the soil, you’re creating great microbes and nutrients for future plants.