Cover Crops

If you’re not planting a fall garden, don’t leave the beds baron. Leaving the mulch on the beds is OK, but a cover crop would be better. A cover crop is a special plant or group of plants that is grown to protect and improve the soil when a cash crop like garden crops are not grown. We have winter cover crop seed of Crimson Clover, Hairy Vetch pea, and Elbon Rye. These are the three most popular and beneficial cool season cover crops here.

Elbon rye is called a green manure and is my favorite. It is a cereal rye, not a lawn grass rye. It is intended to soak up and store nutrients in its extensive root system and also its foliage to prevent the nutrients from leaching away during the winter. It gets 3 feet tall or higher, usually in the spring. It is the most cold-hardy of the winter cover crops. It is grown in Canada. You cut it down in the spring with a weed-eater or hedge clippers to use as mulch for your garden. It then gradually decomposes to return the nutrients back to the soil. And just like compost, it leaves a high carbon humus material behind that gradually changes the soil for the better both physically and chemically. Malcolm Beck, http://www.plantanswers.com/malcom_friend.htm, says he turned poor farm land into prime fields in about 10 years using cover crops including Elbon Rye and a vetch nitrogen fixing legume, between cash crops: https://www.amazon.com/Lessons-Nature-Malcolm-Beck/dp/0911311807.

The deep extensive root system of Elbon Rye also helps to hold loose soils together to reduce erosion, or helps to loosen heavy compacted clay soils. As the roots die, passage ways are left to allow oxygen, water and nutrients to reach other roots. Overall long term drainage also improves

Elbon Rye is also an excellent nematode trap crop for bad, root eating nematodes like the root knot nematode. The nematodes infect the roots, but can’t get out and die. The decomposition of the rye will stimulate soil microbes that help control nematodes also. Don't apply the good nematodes to the garden beds if you are planting Elbon Rye. If you buy flower or vegetable transplants to put in your garden, check the roots for strings of knots or nodules that are caused by root knot nematodes and throw them out to avoid introducing them to your gardens.

Along with shading out weeds, when Elbon rye is chopped down, the decaying foliage releases allellopathic chemicals that prevent smaller seeds of weeds, grasses, and garden plants, from germinating for about a month afterward.

This allellopathic trait is one I use not just in the garden but over my entire back yard and alley where the city doesn't see it from the street and so doesn't mind the 3 foot winter grass. I heavily over-seeded what St Augustine I had at the first of November to give the St Augustine as much time to build up nutrients for the winter as I could. The seed is cheap so I used more than was needed to ensure enough washed down to the soil to germinate into an adequate cover grass. In April and May I watch to see when the St Augustine started growing again and mowed down the Elbon rye so as to not hinder its growth. It will not come back. After three non-consecutive years of applying Elbon Rye, the St Augustine has spread over the whole yard and alley and weeds are not a problem. I see some weeds before the warm season grasses come out of winter dormancy, but they disappear when the grass take over.

Plant from September to the middle of October to get a good, winter cover and a good uptake of nitrogen and other nutrients from your garden soil. You can plant it ¼ to ½ inches deep at 1.33 to 3 pounds per 1,000 sqft or broadcast it on the soil at 2 to 4 pounds per 1,000 sqft .

"Elbon" is Noble spelled backwards, for the The Samuel Roberts Noble Foundation in Ardmore, Oklahoma (http://www.noble.org/), where it was developed. They are known worldwide for this cover crop which shows how important a cover crop can be to the soil.

Hairy Vetch is a pea and therefore a legume, as is Crimson Clover, and can harbor nitrogen fixing bacteria within its roots to add fertilizer to the soil. The plant feeds the bacteria sugars from photosynthesis and the bacteria feeds the plant nitrogen. Legumes look for these bacteria in the soil to infest their roots. The vetch is a climbing vine that can take advantage of planting at 20% Hairy Vetch to 80% Elbon Rye to increase the cover crop biomass by giving the vetch something to climb up on. They have pretty purple flowers too. Crimson clover is a beautiful flower when grown in a nice prepared bed as a wildflower, though it is not a native wildflower.

From what I've read, legumes take advantage of nitrogen fixing bacteria if the soil is depleted of nitrogen, but will not use them as much if the soil is fertile. No need to share if you don't have to. They also utilize the bacteria more as needed when it is time to grow flowers and seeds. So you need to let the legumes at least flower. All of these cover crops need to be cut down before they go to seed in the spring, or the neighbors will be enjoying them next winter too. The rye and clover will die as it warms up, but the hairy vetch can linger through the summer. Both the clover and the vetch have deep taproots that, along with Elbon Rye’s extensive roots, helps aerate the soil when they die.

All of these seeds need to be started like any seed in that they need to have soil contact and be kept moist until they germinate. Water once or twice a day until they sprout.