Cover Crops: What’s Next?

As our thoughts start to turn to our spring gardens, many of you are wondering what will happen with the cover crop that is in the ground. I have heard from many of you that your cover crop has grown quite tall. Even if you got a late start and it is growing but small, having some cover in the ground over the winter has been beneficial to your soil in many ways.

Now, with spring starts about 6 weeks away, it is almost time to think about chopping down your cover crop.

Why did we plant a cover crop in the first place if we’re just going to chop it down?

We plant cover crops for a variety of reasons. First, to protect the soil when it does not have another crop growing. If anyone had the opportunity to see the Kaisers speak at Sierra Harvest’s  recent Food and Farm Conference, you will have a deepened understanding of why its good to keep the soil covered at all times. Cover crops help protect the soil from erosion due to wind and water and other forces. Those good old roots hold everything in place. We also covered your beds with straw to provide extra cover while the seeds germinated and grew. Just using straw to mulch would be beneficial in and of itself, but actually planting a cover crop has all the added benefits you will see below.

Cover crops provide an additional source of organic matter that helps improve soil structure, in part by recycling nutrients and mobilizing them in the soil profile in order to make them more readily available to whatever you plant next. Some of the plants in your cover crop mix are legumes (beans, peas) that specifically fix Nitrogen in the soil, a nutrient that is necessary for plant vegetative growth. This photo shows Rhizobium Bacteria root nodules containing Nitrogen. For fun, try pulling up one of your bell bean or cow pea plants and see if you can find some!3-cover-crop-rhizobium-root-nodules-gettyimages-Large.jpg

Check out this link to find out more about the cover crop mixture that was planted in your garden:

The combination of green plant matter and straw also add essential nutrients and organic matter to your soil once incorporated, helping to increase over all soil structure, fertility and water holding capacity. You will appreciate that when it is 100 degrees and you want to get the most out of your drip system. Your plants will appreciate it too!

In order to get the most benefit from your cover crop, you must chop it down and incorporate it into the soil to let it break down. I recommend doing this soon, since the time frame for decomposition takes some weeks, and you want to be ready for spring starts when they come in early April.

Here’s what you do:

  • Peel away the layer of straw covering your ground and place to the side. You will use this again!
  • Chop down your cover crop. The smaller the better….smaller pieces mean more surface area for the decomposers to get to work on, therefore resulting in quicker decomposition. Use hedge trimmers, loppers, hand pruners, a spade or whatever you’ve got to chop things up as small as you can. No need to pull the plants up…in fact it is preferable to leave the roots in the soil and just chop up the above ground parts.
  • Using a digging fork, turn the soil just enough to incorporate the newly chopped green matter from the cover crop. Then cover with that straw you removed earlier. OR….you can let the chopped cover crop lay on the surface of the bed and cover with straw. It may take a little longer to break down this way. The important thing here is to not remove any of the green matter from your beds.
  • Leave chopped green matter for the next few weeks to allow it to decompose. When the time comes for spring planting in mid March, you may choose to either rototill, turn by hand what remains of your cover crop in, or follow a more no-till practice and plant directly into the bed as is. Either way, your soil has received the benefit of the cover crop.

Time is of the essence! Ideally this should happen within the next couple of weeks so that your beds are ready for their first spring planting in early April.