Learn to Grow: Cover Crop

Learn to Grow: Cover Crop

Cover cropping has gained a lot of attention in the last few years and it's not hard to see why. It's one of the easiest ways to improve your soil structure and health. It also has the added benefit of helping with erosion control and weed suppression. All good things! 

So let's break down some of the most common questions.

Who should plant cover crops?

Everyone! Unless you're blessed with the perfect tilthy loam, it's going to take some effort to get your soil the way you want it. This won't be a sprint to the finish line, but a journey. And remember, no growing area is too small to benefit from cover crops. 

Which cover crop should I plant?

The cover crop you choose should be based on your soil type. (Haven't done a soil test? Now is the time to get it tested.) If your soil is very heavy and compacted (read clay), then you'll want to incorporate crops that have deep root systems such as oil seed radish, turnip, and mustard. If your soil is a more loamy consistency, then you might want to consider shallow root crops such as oats, rye or phacelia. Using a mix of these crops will ultimately give you a more diverse soil structure which can lead to better soil health. Healthy soil grows healthier plants. And because we love a good chart, below is a helpful cover crop chart from the USDA.


USDA Cover Crop Chart


When should I plant my cover crop?

Generally speaking there are two different types of crops, warm weather and cool weather. Warm weather cover crops are usually planted in areas that are selected to remain fallow in order to build healthy soil for the following season. They can also be used if you decide you only want to grow a spring and fall producing garden. After your spring garden has finished, you could then immediately sow a warm weather cover crop. Cool weather crops are often used as a "holding crop" in active growing areas over the winter months. This keeps your soil covered which helps reduce wind and water erosion. It also helps suppress those late winter and very early spring weeds. Whichever crop is planted, it needs to be in the ground long enough to mature and densely cover the soil. 

When and how should I terminate my cover crop?

The most important thing to remember is to terminate the cover crop before it sets seed. Even a well-intentioned cover crop can become a weed if left uncontrolled. A general guideline is to terminate the cover crop two to four weeks before you want to plant. Some growers choose to till in the cover crop. This is the fastest way to incorporate the residue into your soil. If you choose not to till, the easiest way to terminate is to mow or weed eat the crop, leaving the residue in place. You can then cover with a silage tarp or billboard. It's possible to cover the crop with a tarp without cutting it down, but it will take longer for the crop to break down and you also risk the wind lifting and moving the tarp. 

Follow up tips:

1. Like everything else in the world of gardening, there's no one-size-fits-all when it comes to cover cropping. Your individual growing space has its own unique properties and only you (and your soil testing lab and extension agent) will know the best path to take.

2. Plant your cover crop densely and keep it moist until it sprouts. It should look like a carpet of green as it's growing.

3. If you choose not to till in your cover crop you will have better luck in using transplants as opposed to direct seeding into the broken down residue. Any unbroken down residue acts like a mulch which helps regulates temperature, moisture and suppresses weeds, however it can also suppress the seeds you want to grow.

Don't get caught up in trying to discover the 'magic' seed combination to plant.  Cover cropping, even if done poorly, is better than not cover cropping at all.  



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