Winter Cover Crops Common Questions, Answered

by Matt Gibson

Cover crops, also known as green manures or catch crops, are plants that should be planted during the winter in areas of your garden that would otherwise remain bare during the freezing season.

Good cover crops not only protect the soil from erosion over the harsh winter months, but also protect beneficial life that lives in the soil that would remain bare without the help of cover crops. Dig the cover crops into the ground at the end of the growing season to add nutrients and organic matter to the soil and prevent erosion, which will help the next round of plants that you grow.

Cover crops also add important plant nutrients such as nitrogen, phosphorus and potassium, as well as micronutrients back into the soil that has been drawn away by the vegetables you grew previously. Growing these cover crops in your home garden helps returns nutrients to the soil makes them available to future vegetable crops.

Don’t believe us? Check out this comprehensive guide to cover crops and soil health by the USDA.

What are good cover crops?

In areas with heavy soil, cover crops such as cereal rye, which has deep and fibrous roots, will help to improve the soil structure beneath them by helping to break it up, making it lighter. Mustard is another great cover crop for heavy soil, as it grows very fast and will add lots of organic content to the soil when it is dug into the ground in late winter.

Adding large amounts of organic material will help lighten up heavy soil as well. Mustard is an especially good crop for clay-heavy soils, where it can be dug into the ground early, before the winter freezes, so that the winter frosts have a chance to break the soil up and incorporate the organic content. Corn salad, mache, or other prolific salads can also be grown like this and broken down into the soil over winter.

Cover crops can also be grown specifically to suppress weeds and keep them from growing up in a particular area. Cover crops that are good at suppressing weed growth include Phacelia and Buckwheat. Phacelia not only suppresses weed growth but improves soil structure, while its stunning flowers draw in bees and hoverflies. Buckwheat suppresses weeds, and helps enrich the soil and provides a rich source of nectar to attract bees and other beneficial insects in the spring.

In poor soil conditions, its best to choose a cover crop that adds nutrients directly to the soil. Legume cover crops, such as winter field beans and peas, clover, and vetch are all great choices. These are also great picks to dig into the soil before sowing nitrogen hungry crops such as cabbage and other brassica plants.

Other good cover crops include: winter rye, annual ryegrass, hairy vetch, and red clover. Check out our winter cover crops guide for more information.

Cover crops provide a cheap source of nutrition for your future garden plants, when they are turned under and allowed to decompose into the soil. They increase the organic matter of the soil as they break down.

Can you plant cover crops for home gardens?

Yes. You have quite a few options for planting a cover crop for your home garden. We love this University of Minnesota extension page that explains how to do it, and some of the best options to plant as a cover crop. Mother Earth News also has a nice explanation of how it benefits home gardeners.

How late can you plant cover crops?

The end of the summer is the best time to sow cover crops for the upcoming winter, though they can be planted later in mild climate areas. As the temperatures get colder, you’ll need to plant more seeds as a lower percentage will successfully sprout.

What are the best cover crops for nitrogen?

The best winter cover crops for fixing nitrogen are winter field peas and beans, clover and vetch.

Is winter rye a good cover crop?

Very hardy and frost resistant, winter rye is a great choice for a cover crop. Plant winter rye in early to late autumn after your vegetable crops have been harvested. When it begins to regrow in the spring, plow under it and work the biomass into the soil to work in organic matter for the upcoming growing season.

Cover crops are essential to revitalizing and repairing soil for future growth. If you try your hand gardening year after year without planting cover crops, you will be disappointed with the production levels, which will suffer a steady decline each year without some type of help replacing soil nutrients.

How late can you plant cover crops?

If you plant cereal rye, it’s never too late. This hardy seed might not do much when you initially plant it, but it will sprout when the temperatures are consistently over 40 degrees Fahrenheit in the early spring. Otherwise, the best way to find out which cover crops exactly you can still plant during a certain time of year is to contact your local County Extension Agent. They are experts in your local area.

Want to learn more about winter cover crops?

Gardening Know How covers Cover Crop Planting Guide

GrowVeg covers Recharge Soil This Winter

HGTV covers Planting Winter Rye

Hobby Farms covers 5 Cover Crops for a Small Scale Garden

Modern Farmer covers How to Grow Crop This Fall