Winter is an important time to rest both for the gardener and the garden, but it can also be a productive period. It is a great time to work on building healthy soil, which can improve your harvest for years to come. One of our favorite ways to improve soil is by planting cover crops. They’re fairly low effort and provide big rewards! Now is a great time to establish some cool season cover crops in your garden.
Benefits of Winter Cover Crops
Winter cover crops have surprising benefits, even in small gardens. You don’t need a large farm to reap the benefits of cover cropping.
- Add organic matter to the soil.
- Protect soil from erosion.
- Improve fertility.
- Provide habitat for beneficial insects, microorganisms, and fungi.
- Suppress cool-season weeds.
- Improve moisture control and heavy clay soils.
How to Choose a Cover Crop
When selecting a winter cover crop, there are a few considerations. Does your soil have a specific issue? Is it compacted? Does it have low fertility? They should all be taken into account when choosing a crop.
However, one of the most important things you want to consider is how you will use the land in the spring. If you need to get a crop on the land in early spring, you may want to choose a winter kill cover crop. However, if you want to suppress early spring weeds, you may want to select a winter hardy cover crop that will continue putting on growth next spring.
Note that what crops are considered winterkill versus winter hardy depends on your location, hardiness zone, snow cover, and winter temperatures. Understanding your hardiness zone and looking at each crop’s specific requirements can help you make an appropriate choice.
There are benefits and drawbacks to both winterkill and winter hardy cover crops.
Winter Hardy Cover Crops
Winter hardy cover crops are those crops that can survive winter temperatures. They don’t necessarily grow all winter long. Instead, they go dormant when it’s very cold and put on growth when conditions allow it. For some areas of the Southeast, this may mean you see some growth through the winter. However, in mountainous regions, winter hardy cover crops will often put on growth in the fall and then again in the spring.
These winter hardy cover crops have the added benefit of out competing spring weeds. As they establish root systems, they tend to encourage more biological activity in the soil than a winter kill cover crop.
Winter Hardy cover crops tend to put on vigorous growth in the spring as the daylight increases and temperatures begin to rise. This growth can be good for suppressing weed growth, but you must also manage these crops as you prepare to plant.
Mowing and tilling winter hardy cover crops under is a popular option. Some no-till farmers prefer to use tarps or crimping to kill the crop and leave it lying on the bed as a mulch to plant into. However, as the mulch begins to break down it can temporarily tie up nitrogen. To mitigate this risk, you may want to wait 2 to 3 weeks before planting into that bed.
There are many winter crops ideal for fall sowing. Here are a few of our favorites:
Winter Kill Cover Crops
Generally, we plant winter kill cover crops a bit earlier than winter hardy cover crops. The goal with the winterkill cover crop is to allow them to put on good growth in the late summer and fall so that when they die during the frosts of late fall or winter, they provide a covering of mulch on the soil. This mulch helps provide a habitat for beneficial insects, insulates the soil, and adds organic matter as it breaks down.
In the spring, beds with winterkill cover crops are ready to plant immediately. You can lightly till the crop residue into the soil or leave it on the surface. Generally, it’s easy enough to rake to the side for seeding or to transplant into if you have seedlings.
Unfortunately, depending on where you live, these winter kill cover crops need to be sown early. As the main goal is to create biomass, you need to allow them plenty of time to grow before they’re killed off by frost.
As with winter hardy cover crops, precisely what is considered a winter kill cover crop in your area depends on your climate. For example, daikon radishes are often considered winter kill cover crops, but this may not be the case across parts of the Southeast. Daikon radishes are only killed where temperatures regularly drop below 20°F.
Here are a few of our favorite options for winter kill cover crops:
- Buckwheat
- Daikon Radish
- Oats
- Sorghum
- Sudangrass
Mixing Cover Crops
Want the best of both worlds? Consider trying a mix of crops. Many winter kill cover crops are better suited to tolerate the southeast warm fall temperatures. Mixing them with a winter hardy cover crop can provide a little shade and protection for the winter hardy crop to get established. As the winter kill crop begins to die back, the winter hardy cover crop will grow and continue to grow in spring.
If you want to learn more about using winter cover crops in a no-till system, check out this article on Organic No-Till Cover Crops by our neighbor Pam Dawling, the author of Sustainable Market Farming.
It’s time to build healthy soil! Try adding some of these winter crops to your garden to add organic matter, improve fertility, prevent erosion, and more.