August is the time to start planning for a fall vegetable garden, and those looking for a successful season should consider adding cover crops into the rotation.

Healthy soil is key to a flourishing garden. By planting cover crops, gardeners can maintain and build the healthy biology of the soil while reaping a variety of seasonal benefits.

The advantages of cover crops include providing winter interest, shading the soil from excessive heat during the summer, and breaking pest cycles when used strategically, according to Fairfax County Master Gardeners.

In Virginia, the four main cover crop categories are grasses, legumes, brassicas and forbes.

Grasses such as cereal rye grow later in the season and are popular for their ability to scavenge nutrients. Brassicas like forage radish are useful for relieving soil compaction, scavenging excess nutrients and suppressing weeds. Legumes like hairy vetch and crimson clover are best for fixing atmospheric nitrogen and providing a nitrogen source for later plantings.

Cultivating a mixture of cover crops produces the best results, as soil and weather conditions vary from year to year. Combine legumes and non-legumes whenever possible.

Winter cover crops are typically planted as early as mid-August but no later than mid-October—they need to germinate and become established before the first hard frost.

You can sow a cover crop while vegetable crops are still producing by removing mulch from around plants and raking the area smooth. Your cover crop will have a good start without interfering with current vegetable growth.

Popular fall-planted cover crops include oats, winter rye, field peas, crimson clover and hairy vetch. Hardy vegetables like brassicas, mustards and Asian greens also can provide winter soil coverage.

Visit the Fairfax County Master Gardeners website for more information on planting cover crops in the Mid-Atlantic Zone 7b climate. The Master Gardeners of Northern Virginia also offer recommendations for winter cover crops to plant in August to early fall.

Refer to your local Extension Master Gardener program for gardening recommendations specific to your hardiness zone. To find your local Extension Master Gardeners, reach out to your local Virginia Cooperative Extension office or search the web or Facebook.