Our mild autumn temperatures have accelerated the growth of fall-planted, over-wintering, cover crops.
Back in October I wrote about planting cereal rye as a cover crop in my garden. Since then the crop has germinated and made excellent progress toward establishing itself.
When rye seed germinates, it emerges out of the soil as a single shoot. As time goes by and temperatures are conducive to plant growth, leaves begin to form on the main shoot.
After a couple of weeks of growth, the plant enters the “tillering” stage of development.
Rye is a bunch grass, a self-descriptive term meaning that the plant grows in tuffs or bunches instead of spreading by over-the-ground stems called rhizomes. To spread and take advantage of growing space, the bunch grasses form extra stems called tillers. Tillers grow from the main stem of the plant.
When you look at a rye plants and see it staring to form dense tuffs, that growth you see is the tillers. Each tiller has the ability to form it own roots. In that way the plant has the ability spread vegetatively, essentially producing baby plants along side the main plant.
Farmers are concerned about encouraging tillering because the more fully-developed tillers the crop has, the greater the yield.
Extra tillering allows the plants to fill in bare areas thereby compensating for thin stands or weak germination.
My rye is is in the early stage of tillering and should be in fine shape going into the winter.
I closed the garden down during the third week of October this year hoping that the weather would stay mild so my cover crop of rye would germinate and make some good growth before winter sets in.
Rye is one of the best winter cover crops for our area. You can let your garden grow for a full season and still have time to plant your cover crop after the garden has stopped producing. Fall-planted rye will make good growth and do very nicely over winter, especially if we have a covering of snow to protect the plants from harsh winter winds.
On sloping sites, cover crops such as rye, stabilize the soil keeping it from washing downhill. On flat sites, cover crops keep wind from blowing away your hard-earned topsoil.
It’s true, you can just leave those small fall growing weeds in your garden and they will do much to control erosion but rye has another huge advantage. A cover crop of rye will reduce the bio-mass of weeds by 80-90% vs an area with no cover crop. Because it grows so fast in the fall, rye will smother weeds that are trying to grow. Not only that, its roots produce a compound that keeps weed seeds from sprouting. Compare that to a garden that is covered with small over-wintering weeds waiting to grow again in the spring and you’ll see what an advantage that is.
You can’t actually see it with your eyes but soil nutrients can get washed down into the soil profile by autumn rains and melting snow far enough where it is no longer available to your garden plants. As it grows, rye will capture soil nutrients retaining them in the form of roots, leaves and stems.
Another fascinating thing about rye is that it has the ability, unlike many other plants, to extract usable minerals directly from raw soil particles. It then uses the minerals for its growth and development — essentially making its own fertilizer. In the spring, the rye plants are tilled into the soil. As they decompose, these new minerals are released into the soil for garden plants to use.
I prepare my garden for its cover crop by first removing much of the existing plant material, mostly the stuff that tends to get caught up in the tiller tines. Then I’ll run the tiller over the garden to mix in the plant debris. At that point the area is ready for seeding. I evenly broadcast about three pounds of rye seed per thousand square feet evenly over the area. Then I make a very shallow pass with the tiller to mix the seed into the top couple of inches and I’m done.
Keep in mind you are not planting a lawn here. Too much seed will give you a dense rye plant population making it very difficult to till under your rye crop in the spring.
It’s not your imagination, the growing season is winding down early this year. The excessive rain and cooler than normal temperatures in our area have combined to make it a challenging season for many garden plants especially the warm weather crops like tomatoes or peppers.
Farmers are noticing it too. Many field crops never fully recovered from poor start of the season and are showing signs of maturing early. As a result there may be a reduction in yields as well.
Certain beds in my garden are already kaput. But there is a silver lining in that. It gives me a chance to plant a green manure crop, which I don’t often get to do.
The terms green manure and cover crop are basically synonymous. Green manure is a crop that will be turned over into the soil while still growing, a cover crop may or may not be turned into the soil right away.
These types of crops are great for recovering soil nutrients from the soil and holding them until next year’s planting season. Some soil nutrients such as nitrogen are easily washed down into the soil profile by fall rains or melting snow putting them out of reach of most garden plants. Much of that valuable garden nutrients that you worked so hard to build up could be lost.
Multiply the nutrients over hundreds of acres and you can see why farmers use cover crops to save money and protect the environment at the same time. Nutrients that stay in the field will not get washed into steams and rivers where they end up being a source of water pollution.
In other words, green manures effectively “mop up” nutrients and hold them in place until they are needed next year.
In a garden situation, the biomass that a green manure crop adds to the soil may be more valuable than the nutrients they conserve. You really can’t have too much organic material in garden soil.
A cover crop also provides a better habitat for soil microbes to flourish as opposed to bare soil.
Planting cover crops is a fairly advanced technique for home gardeners even though it is very effective for both vegetable and flower gardens.
If this is your first time planting cover crops, consider oats, yes the same plant that is harvested and used for making your breakfast cereal. They make a very effective cover crop.
This time of the years we are looking for a plant that will make quick growth and oats fit the bill. Even though they grow quickly, they should be planted very soon.
The other big advantage that oats have is that they will die over winter leaving a mulch on the soil surface that can be tilled in next spring. That also eliminates the possibility that they may become a weed in your garden. I’ve had winter wheat come up in the spring — seeds from straw mulch — and before I knew it they became a problem. Have you ever tried to pull up a well established clump of wheat? They’re pretty tough plants.
Planting oats is much like planting grass seed except the seed is much larger.
Sow oats at a rate of two or three pounds per 1000 square feet about an inch deep. Farmers use an implement called a seed drill to plant oats. The easiest method for a gardener is to broadcast the seed by hand, then till very shallowly with a tiller. Finish off by lightly pressing the area down so the seeds make good contact with the soil.
Farm supply stores sell oat seed however you may have to go online to buy small quantities.