Cover Crops

Cover crops are an alternative way to manage soil fertility in agricultural systems; they can be a living mulch or incorporated into the soil as a green manure. Sometimes one crop can cover multiple needs.

Florida’s sandy soils tend to have low soil fertility as well as low water and nutrient retention because of their low organic content. Cover crops increase soil fertility by adding organic matter.

Farmers can grow cover crops between crop cycles (such as vegetables) or intercropped among crops (such as ground cover in orchards).

Cover Crop Uses

Cover crops are sown to:

Control weeds through competition for available space, light, water, and nutrients
Prevent soil erosion caused by heavy rainfall or winds
Protect crops (such as watermelon) from sand blasting damage
Retain and harvest residual nutrients that would be leached in the off-season
Recycle and restore nutrients in a crop system
Reduce select harmful nematode populations
Create additional income (such as hay production)
Provide mulch cover for row middles and/or mulched beds
Provide habitat for beneficial insects and birds

Although cover crops have many benefits, improper selection of cover crop types can create challenges. Some may be too weedy, woody, and/or tall, which can interfere with cultivation and harvest. Others may harbor pests and diseases.

Some of these challenges can be avoided by cultural practices such as mowing, but the easiest way to prevent unwanted effects is to identify and plant cover crops that suit your needs.

Types of Cover Crops

The main distinction in cover crops is between annual cover crops intended for a season and perennial crops that will last for many years. Annual crops can be grains/grasses or legumes (those that produce nitrogen), and are either summer or winter crops. Winter cover crops are adapted to shorter, cooler days, while summer crops are better for hot, long-hour days.

Choosing a Crop

Species suited for cover cropping in Florida are listed below in Table 1. Because of South Florida's climate, winter cover crops may not be ideal choices for cultivation. Crops appropriate for South Florida are marked with an asterisk.

Cover crops can be chosen for purposes such as soil protection, nitrogen production, or creating residues for incorporation into the soil. Variables such as decomposition rates, herbage (biomass), and classification determine how well a cover crop is suited to a specific purpose.

Finding the best cover crop for your specific needs may take some patience and experimentation with different crops, crop combinations, management practices, and use of appropriate technology. Growing multiple species can increase the performance and adaptability of a cover cropping system, especially when growing conditions are less favorable for one of the species.

Cover cropping was a large part of past Florida farming practices, so it may be worthwhile to take advantage of the experience and knowledge of older farmers in your region who farm similar soils and have used cover crops successfully.

Table 1. Cover crops for Florida (*South Florida compatible)

Crop & Seeding Date	Yield-Biomass (lbs / acre)	Yield-Nitrogen (lbs / acre)	Seeding Rate (lbs / acre)
Annual Winter Cover Crops
Leguminous
Crimson Clover Oct. 1 – Nov. 15	1500 – 5000	35 – 120	20 – 25
Hairy Vetch Oct. 1 – Nov. 15	2000 – 4000	35 – 150	20 – 30
Lupine* Oct. 1 – Nov. 15	2000 – 4500	45 – 120	30 – 45
Grain
Black Oats Oct. 1 – Nov. 15	1500 – 3500	20 – 40	80 – 100
Winter Rye Oct. 15 – Nov. 15	3000 – 6000	30 – 50	80 – 100
Annual Summer Cover Crops
Leguminous
Aeschynomene* Mar. 1 – June 30	2000 – 4000	50 – 100	6 – 8
Cowpeas* Apr. – Aug.	4000 – 6000	50 – 90	6 – 8
Hairy Indigo Mar. 15 – May/June	7 – 10 tons of greenchop/acre	80 – 150	6 – 10
Sunhemp* Mar. 1 – June 30	4500 – 10,000	90 – 180	30 – 50
Velvetbeans* Mar. 1 – June 30	2200 – 4000	50 – 85	30 – 50
Grain
Sorghum-sudan Mar. 1 – June 30	6500 – 9500	55 – 80	24 – 30
Perennial Cover Crops
Leguminous
Rhizoma Peanut Dec. – Mar.	2000 – 10,000 (12 months)	50 – 130	80 – 100 bu of rhizomes/acre
Grass
Bahiagrass* Jun. - Aug. if rainfed	3000 – 8000	55 – 140	15 – 20