Cover Crops - Summer and Winter

Why should I plant a summer cover crop?

You can get a head start on improving the quality of your garden soil for next season with some simple steps taken in the summer - boost the amount of organic matter in your soil with summer cover crops.  A summer cover crop will add significant amounts of organic matter to your soil, yielding a variety of long term benefits. Increased organic matter improves the water holding capacity of soil, improves drainage in clay soils and provides a range of macro and micro nutrients that optimize plant health. In a recent study conducted by a university Ag Department in the mid-west, plants that were grown in soils amended with compost did significantly better than those grown in un-amended soil.

Summer’s the perfect time to fix problem soil, so why not go all out! Work 1½-2” of compost into soil before planting your cover crop and you’ll have a vital foundation for future vegetable gardens. After compost has been added just scatter some seeds, water and before you know it you’ll have a carpet of green. A crop of hairy vetch and rye will add nitrogen equivalent to 13 pounds of 10-10-10 fertilizer and 57 lbs. of biomass to a 400 ft garden.
 

What are the best seeds to use?

There are several choices for cover summer cover crops in our area. Legumes of any kind make a great cover crop (peas, beans, soybeans, etc.) because they add significant amounts of organic matter and help fix nitrogen in the soil by taking it from the air and passing it into the soil through nodules on its roots.  Buckwheat is another great choice. It’s known for its ability to keep unwanted plants in check, making weeding even easier. It matures quickly and can be tilled or dug in in as little as 4-5 weeks. (Remember that even if the cover crop doesn’t reach full growth while in your plot, whatever green stuff is there when you turn it into the soil will make a difference.) It also has pretty white blossoms but be sure to cut them before they go to seed. Another fast grower is annual rye grass which yields huge amounts of organic matter after only several weeks of growth.
 

How do I do it?

If you can sow seeds you can grow a cover crop. Whenever you have an area that’ll be unused for more than a few weeks, a cover crop can go in. Scatter seeds over the area, rake them in - more vigorously for large seeds like peas- and then water just like you do the rest of your garden. If there is enough time for the crop to get several inches high turning it under is easier if you mow it first. The mowing also chops the plants into smaller pieces which will break down more quickly in the soil. The plants should be turned in when they are in about 75% flower or, for buckwheat, when frost is near, whichever is sooner.  A series of cover crops can be grown, one right after the other, if there is enough time in the season. 

What about winter cover crops?

You bet! Cooler temps limit the variety of cover crops we can successfully grow, but there are a couple that will do the job.

For organic matter -  Winter rye is excellent. It grows vigorously and produces lots of green stuff to turn under come spring. Just remember to turn it under at least 2 weeks (more is better) before you wish to plant your edible crops.

For nitrogen fixing -  Austrian winter peas or hairy vetch produce a surplus of nitrogen fixing legumes for spring turning. And those few that don’t get turned in will give you some lovely blossoms, interesting greenery and make for some very happy bees!

Where can I get the seeds?

Check with your local nurseries or garden supply centers. If they don’t have what you’re looking for, click on Peaceful Valley Farm Supply - they’re a great source of many different types of cover crop seeds.

Remember, building your soil through the addition of organic matter is one of the best things you can do for your lawn and garden. Naturally!

Keep in mind the benefits compost offers lawns. A fine layer of compost spread over grass is called top dressing. Experts recommend top dressing lawns twice a year; during spring and fall. For the more info on lawn top dressing, click here.