So, maybe you’ve decided it’s just too hot to be outside tending to your garden. The humidity, the heat, the insects, the rain—being a gardener in zone 10A in the summer isn’t always fun.
If you decide not to plant anything, do you know what will happen? First, the weeds will take over. With all that bare ground, you’re not putting in any plants to compete, so the weeds have free rein. The blazing sun will beat down on your soil, destroying its structure.
The torrential summer rains will wash away all the good nutrients and encourage soil erosion. The sun and rain together will compact your soil, making it hard and less fertile.
Plus, the beneficial insects that help control pests will leave if there’s nothing to keep them around. Without them, you’ll be missing important allies when you need them most. That’s a pretty rough situation!
Cover Crops to the Rescue!
If you’ve decided not to garden during the summer, may I suggest a cover crop?
A cover crop is a type of plant grown primarily to protect and improve the soil rather than for harvest. These crops are planted during the off-season when the main crops are not being grown. Cover crops offer several benefits.
First, they help prevent soil erosion by holding the soil in place with their roots. Second, they improve soil health by adding organic matter when they decompose. Third, cover crops can suppress weeds by covering the ground and preventing weed seeds from germinating.
Fourth, they help retain soil moisture, reducing the need for frequent watering. Finally, some cover crops, like legumes, can add nutrients to the soil by fixing nitrogen from the air.
Using cover crops is a smart way to maintain and improve your garden’s soil health. The best thing about cover crops is that they take little to no care from you!
Enter Sunn Hemp
Sunn hemp is a warm-season cover crop. It comes from India, where it is grown for fiber, forage, and as a cover crop. It is grown in the U.S. for the same reasons and is becoming increasingly popular in Florida.
Sunn hemp residue adds nutrients and organic matter to the soil. As a soil builder, most studies of vegetables planted after sunn hemp have found increased vegetable yields.
Additionally, the plant delays the germination of weed seeds and disrupts the life cycle of nematodes.
Forage crops are harvested and used as livestock feed for animals such as cows, sheep, goats, and horses. These crops provide essential nutrients and are an important part of animal diets, often used in the form of hay, silage, or fresh pasture.
Growing forage crops helps ensure that livestock have a reliable source of food, especially during times when natural grazing is not available. If you are homesteading and have livestock, growing forage crops can be a great solution for a summer cover crop that also provides valuable feed for your animals.
A Legume, Not a Hemp
Sunn hemp (Crotalaria juncea) is considered a “hemp” because it has historically been cultivated for fiber production, similar to hemp. However, sunn hemp is actually a legume from India, while hemp (Cannabis sativa) is a non-legume from China. In case you were still wondering, sunn hemp does not produce cannabinoids while hemp does.
As a legume, sunn hemp has nitrogen-fixing abilities, making it an excellent choice for enriching soil fertility. It also suppresses nematodes, thrives in hot climates, tolerates drought conditions, and has the unique ability to extract nutrients from deep within the subsoil. It will require watering up to and a few weeks after germination, but once established, it needs very little care.
Sunn hemp does not have any major disease or pest problems, especially in Florida. However, deer, wild hogs, and rabbits find this cover crop desirable and may destroy it in some areas.
Sunn hemp is day-length sensitive and produces vibrant yellow flowers late in the season. Typically, the plant will not go to seed above the 28 degrees N latitude.
The plant is a vigorous grower, often reaching heights of up to 6 feet within 60 days. It is recommended to mow or cut down the plants when they reach heights of 5 to 8 feet to prevent the stems from becoming overly massive and fibrous.
Sunn hemp is not a cover crop for everyone due to its size. However, if you have a corner spot in your garden that could benefit from a soil booster, sunn hemp may be the perfect plant for you to grow during the hot summer months!
Resources:
- Southern Exposure Seed Exchange: Sunn Hemp Cover Crop
- UF/IFAS: Questions and Answers for Using Sunn Hemp as a Green Manure Cover Crop
- USDA NRCS Plant Guide: Plant Guide – Sunn Hemp