I was looking through some old books on my bookshelf the other day and found one that was a gift from an old friend. Its called 1001 Old-Time Garden Tips, edited by Roger Yepsen and published by Rodale Press. I was interested in seeing what they had to say about cover crops as I have been meaning to try doing that for several years now but just never got around to doing it.
My favorite tip was from a 1908 issue of The Garden Magazine: “Get a pound or two of crimson clover seed now. Just as soon as one row of vegetables is past, out with it and put in crimson clover to fertilize your soil. It is a beautiful plant and make nitrogen cheaper than you can buy it.” This not only seemed like a good idea, it was one I had never thought of before and it would certainly make the task of sewing cover crops easier as it can be done row by row as the veggies fade.
Experienced gardeners know how important good soil is in any crop, be it vegetables or flowers, trees or shrubs. And it is important to replenish nitrogen in any garden, but especially in coastal gardens when we get so much rain and the nitrogen is easily washed away. Too much chemical nitrogen can cause all sorts of problems in our watershed, but cover crops not only will fix the nitrogen in the soil, they do it while they look good, too.
What … you may be wondering…exactly are cover crops? Also called green manure, cover crops are grown solely for the purpose of enriching and protecting the soil. They are sewn into the soil and tilled under before they can flower and set seed. They also stop erosion and keep many nutrients from leaching out of barren soil.
Cover crops are usually planted just after a crop is harvested and the ground cleared of plant matter. The cover crops can then take up the nutrients and keep them near the soil surface instead of nutrients being washed away.
Ah, but there is even better news! If you choose a cover crop that makes a fast, dense stand, they will act as weed barriers over the winter months.
'Dixie' red clover field
Then, when they are turned into the soil in the spring, the crops’ decomposing stalks and leaves enrich the soil with organic matter which not only improves the nutrient-retaining capabilities, but also the soil structure itself. They help to retain moisture (although that is not a big issue here in the winter) and moderate temperature fluctuations. This helps our friends the earthworms.
Sow a winter legume like sweet clover or winter rye by first working the soil lightly with a tiller or hoe to get the bed ready. Scatter the seed evenly and gently rake the soil to cover the seed lightly. If you are sewing any of the clovers, tamp the soil after the bed is sewn which provides the firm seed bed these plants prefer. The seeds will sprout and grow until temps get too cold, which may kill the plants. Other plants will resume growing in the spring. Either way, till them under a few weeks before planting in the spring. Wait a couple of weeks before planting to allow the ethylene gas released by the decomposing cover crop to dissipate so it won’t impede seed germination.
Some excellent cover crops to try are legumes like fava, broad or field beans. This family of winter annuals needs cool weather and ample water, making it perfect for the coast. They do like well-drained soil, too. The annual crimson clover is a crop that should grow all winter long with enough moisture and some loamy soils. It doesn’t like extremely acidic soils, so a little lime worked in before planting the seeds will help here. White clover also likes cool, moist climates, but this perennial legume may prove to be a problem if not worked into the soil before flowering and setting seed. Winter or cereal rye grass has the ability to survive in extreme cold and tolerates acidic soil. It, too, likes moisture but only if well-drained.
The advantage of winter rye is that it grows quickly in the fall until temperatures reach 40 degrees. However, letting it grow too tall in the spring may mean you need machinery to turn it under. Legumes have the added benefit of taking atmospheric nitrogen and add it to the soil. So perhaps the best solution is to plant a mixture of legume and grain cover crops.
When seeded together, the grains grow quickly enough to protect the legumes until they can become established. A symbiotic relationship at its best.
I think I have talked myself into actually planting a cover crop this year instead of just thinking about it.
Comments