Hairy vetch is going strong this winter in a small planting bed at the UC Master Gardener's “Garden of the Sun,” a demonstration garden in central Fresno.
Hairy vetch, common vetch, sweet clover and crimson clover are types of ‘green manure.' Like all legumes, they work with bacteria in the soil to convert nitrogen from the air into a form that plants can use and deposit the nitrogen in the soil. In this small plot, hairy vetch was planted by seed in September after harvesting mini watermelons. The vetch will grow through the winter and early spring and then be cut down to the ground before it sets seed. The top of the plants will remain on the surface as a mulch for cotton, which will be planted from seed in the spring. All the cotton's fertilizer needs will be met by this crop of hairy vetch.
Cover crops are inexpensive and build and protect the soil, however it has one drawback. The area being treated is not available for growing winter vegetables.
The Garden of the Sun, 1750 N. Winery Ave., Fresno, is open to the public Mondays, Wednesdays and Fridays from 8 a.m. to 11 a.m. (except holidays).