Clover proves worthy Cover crops guard against soil erosion

A good stand of clover is a beautiful thing. To be sure, we in Maine may take this rather ordinary looking plant for granted. The deep red flowers of the common red clover are a bit ho-hum compared to some of our more attractive roadside wildflowers. But clover has an edge.

Silently, unobtrusively, under the soil this precious plant is specially adapted for capturing nitrogen from the atmosphere and transforming it into a form usable for our garden plants. In addition to the plant’s ability to “fix” nitrogen, clover plants form a dense, strong-rooted mat of groundcover that proves an invaluable tool for the discriminating gardener. Wisely planned and carefully planted, various types of clover can control erosion, increase organic matter in the soil, improve fertility, minimize weeding and act as a living mulch.

Some gardeners attend to plants’ nitrogen needs through the integration of clover into their crop rotation. Clover can be used as a cover crop or green manure. It may be common knowledge among serious alternative gardeners, but a cover crop is a stand of plants grown on ground that is in rotation or being prepared for future production. Cover crops provide a blanket of living material over otherwise exposed ground, thereby minimizing soil erosion by wind or water. Simply put, a green manure is a crop grown for its nutritive qualities. Generally speaking, green manures are selected plants sown and grown briefly, then turned into the soil to serve as “food” in the soil for the next crop. Cover crops can double as green manure, if scheduled appropriately.

Let’s dispel some misconceptions about cover crops and green manure:

No. 1: Only organic gardeners can use cover crops and green manure. Not true! While the practice is widely used by organic gardeners, anyone – conventional, sustainable or organic – can incorporate cover crops and green manure into their growing systems.

No. 2: Cover crops and green manure can be employed only on large areas of farmland. Again, this is absolutely false! Any amount of land, from square feet to square acres may benefit from these earth-friendly practices. In a commercial agricultural setting, large equipment may be used to get the jobs of sowing, irrigating and cultivating accomplished; on smaller areas of land hand sowing and cultivation may be required.

No. 3: These practices only work for vegetable gardeners. Untrue, again! Flower gardeners can easily sow cover crops and green manure in their annuals beds. Pull out those declining annuals in September and sow a handful of oat seeds in their place. A quick cover will flourish in the cool, waning days of fall, providing cover – possibly reducing soil erosion – during the fall rains. Preparing new beds for next year? Remove the sod, add soil amendments, and seed in a cover crop to hold your ground in place for spring.

No. 4: Cover crops and green manure are perfect in every way. Sorry to say, this, too, is false. While the attributes of individual plants may be great, many have their downsides. Foremost, some can step out of bounds and become weeds if not carefully held within check. It’s a shame to say that those same qualities that may endear the plants to us may also cause us to dislike them. In the wrong place – in the middle of a lush stand of vegetables, say – some can be a menace. Vigorous roots and prolific seeding can turn our beloved cover crop into a weed.

Clover isn’t the only plant that serves as a cover crop or green manure. Next week I’ll share some ideas on other plants that might serve to improve your soil and lessen the number of hours spent fertilizing, irrigating, mulching and weeding.

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, RR1, Box 2120, Montville 04941, or e-mail them to dianagc@ctel.net. Selected questions will be answered in future columns. Include name, address and telephone number.