A cover crop is a quick-growing crop used to cover exposed
ground, prevent erosion or soil compaction, and block weeds. Cover crops such
as buckwheat, clover, rye or other grains and legumes add nutrients and humus
to the soil when they are cut down, turned under, and allowed to decompose in
place. A cover crop that helps build soil health is called green manure.
Cover crops can protect and build the soil in all seasons.
Cover crops protect the soil and the beneficial activity of soil bacteria,
fungi, and earthworms from heavy spring and fall rain, hot summer sun, and
winter winds. Deep-rooted cover crops draw phosphorus, potassium, and trace
minerals to the soil surface at the same time they are aerating the soil.
Cover crops and green manures can be planted
• As a gap-filler between growing seasons or between
plantings of food crops.
• As soil builders in any season:
plant a warm-season cover crop followed by a cool-season or winter-hardy cover
• As a temporary living mulch to
keep weeds down between rows and beds of crops and prevent erosion or
• As a permanent mulch around
perennial vegetables and fruit trees and bushes.
Timing. Cover crops can be planted:
• In early spring to hold the ground until warm-season crops such as
peppers, tomatoes, and melons can be planted; plant early spring cover crops 6
to 10 weeks before warm-season crops turning them under 2 weeks before planting
your vegetable crop.
• In late spring or early summer
(mid-season) after the harvest of spring leaf and root crops and before the
planting of summer or fall crops. A heat-tolerant, fast-growing cover crop such
as cowpeas or buckwheat can bridge a gap as short as one month.
• In late summer or fall
after warm-season crops have been harvested; plant winter cover crops at least
6 weeks before the first killing frost. Some winter cover crops will die with
the first freeze; others will survive winter and begin growing again in spring.
• During growing season as a living mulch to suppress weeds and moderate
soil temperature in hot weather; allow 4 weeks for cover crops to begin
protecting planting beds and surrounding areas as green pathways.
• For a full year to improve infertile or compacted soil or to rejuvenate
worn-out soil. A year-round cover crop can choke out perennial weeds and reduce
root-knot nematodes as well.