How to Grow Crimson Clover as a Cover Crop

Perhaps you've tired of undoing the mat of weeds that greets you each spring -- or your garden sits on a hill. Or maybe you'd like to do away with all the chemical fertilizers and herbicides used to keep a garden growing. In any -- or all -- of these cases, consider planting crimson clover (Trifolium incarnatum) in the fall to keep weeds at bay, control erosion and nourish soil.

About Crimson Clover

• Crimson clover is an annual, meaning it completes its life cycle in one year. The plant is hardy only in U.S. Department of Agriculture plant hardiness zones 6 through 9 so in cooler climates, it will probably die off during winter. Even dead standing plants, however, protect soil against fall-seeding weeds and guard against erosion.
• Turned under in spring, a wealth of nitrogen is trapped in the plants' roots, although plants that live through the winter and bloom in spring retain more of the essential element. This "fixed" nitrogen makes clover, a legume, a superior source of nutrition for depleted soil.
  
• If you have never used crimson clover as ground cover, buy inoculated seed -- seed that has been treated with inoculant type“R,” Rhizobium leguminosarum biovar trifolii. Innoculants may be purchased for mixing. Just make sure to use a Rhizobium labeled for use on crimson clover and follow label directions carefully_._
• Because crimson clover grows best in sunny, well-drained, slightly acidic soil, a garden is a perfect location to use it.

Planting Crimson Clover

1. Clean out unharvested vegetables and cultivate to remove weeds. Prepare the garden so you can seed the clover six to eight weeks before the average first frost date in the area.
   
2. Broadcast inoculated seed over the soil at a rate of one-half pound per 500 square feet of garden.
3. Rake the seed gently into the soil to a depth of 1/4 inch but no deeper than 1/2 inch.
4. Water well if the weather is dry. Clover should begin to grow tall hairy stems dotted with triple leaf sets within 14 days.

Tending and Finishing Crimson Clover

• Water clover only during periods of drought before the first frost.
• Allow clover to stand as it dies. Surviving plants produce spears of red flowers in early spring.
• Mow clover and dig it into the soil four to six weeks before planting your garden. This gives the clover time to decompose and provide green manure, the equivalent of well-rotted animal manure.
  

Crimson Clover Seeds

The seeds of crimson clover are often sown around and in between other crops, such as corn, wheat and soybeans. The plants can tolerate light shade, so in this position it grows relatively quickly and helps to keep down weeds. At the end of the season, as the plant dies and decomposes, this nitrogen goes right into the soil, making it available for other plants. Crimson clover is a winter annual. It does not like extreme hot or cold temperatures, preferring cool and humid weather. Crimson clover grows densely and flowers profusely in full sun, but will also tolerate partial shade. When planted in fall, it grows slowly over the winter, quickening its pace in the cool of early spring.