Planting cover crops is one of the best things you can do for your soil, but how do you choose which one is best for your unique situation?

Choosing a Cover Crop

Since there are so many options, choosing a cover crop is kind of like picking out clothing: How you do it depends on your personality.

If you approach choosing cover crops like I shop for clothes, it’s a mission. I want to get in and get out as fast as possible. For you, I suggest reading “In General: A Grass and a Legume and Maybe Another” below and then skimming to find any parts of this post with bits that help you find what will work for you. If you’re really on a mission, just read “My Easiest Suggestions” before moving on to Planting Rates and Purchasing.

For those who approach cover crops the way I do, you want to learn as much as you can before choosing what you think will work best for you. Hopefully, it’s all here for you, with links to other articles and sources to find out even more. Because there are so many options, there is no one right way, and my attempts to simplify the choices will inevitably create some oversimplifications. Therefore, how and why you choose cover crops once you’re an expert might be different from some of the advice below, but this will get you started well.

For those somewhere in between, follow your heart. There’s a lot here to dig into or skim through.

In General: A Grass and a Legume and Maybe Another

For most winter cover crop situations, choose a grass (e.g., winter rye, wheat, annual ryegrass, barley, oats, etc.) that best fits your area and needs. If you’re new to cover cropping, can’t find other seed, or just want to keep it simple, that’s really all you need to get started.

If you want to do a little more, add a legume (e.g., hairy vetch or a clover). And possibly add another (e.g. tillage/forage radishes) if there’s something it does you want as a benefit (e.g. loosen subsoil).

My Easiest Suggestions

To really simplify choosing a cover crop, especially if you’re just starting out, choose a grass like winter(cereal) rye, wheat, or annual ryegrass. Winter rye (aka cereal rye) would be my number one choice, just because it still germinates well in the cooler temperatures typical of fall planting for a winter cover crop, is very hardy, and is the best at capturing nutrients (known by cover crop aficionados as nutrient scavenging), capturing up to 100% of leachable nitrogen. Wheat would be my second choice and second in all of those categories, and both wheat and rye will provide volumes of mulch and compost material if left on the garden long enough to grow their seed stalks before killing them by mowing. Annual ryegrass won’t provide much mulch or compost material, but it’s just as easy to grow and easy to get.

I’d also add a legume—probably hairy vetch if paired with winter rye or wheat and crimson clover if paired with annual ryegrass, just because they both do well in the same conditions as those grasses and the hairy vetch will use the rye or wheat stalks as support to grow even bigger, providing even more volume for compost and mulch—because the extra nitrogen they fix in their roots and contain in their tissues helps break down the grasses faster after the cover crop is cut, which returns the nitrogen to the soil, garden bed, garden plants, or compost sooner. However, many legumes grow well with grasses, so pick whichever works best for you.

I’d only add a third cover crop to the mix if there’s one you really want to try or one you think really meets your soil’s needs.

For Beds, Consider Winter Killing Cover Crops…Maybe

If you use beds in your garden or just want the ease of not having to kill your cover crop to get the soil ready to plant the next spring, you might want to consider planting cover crops that will winter kill in your zone. For grasses, consider oats or barley. For a legume, consider berseem clover or field peas, especially Austrian winter peas. For others, consider brassicas, like mustards or forage radishes.

There are two challenges, however: First, it can be difficult to get these cover crops fully established between their typical seeding time after garden clean-up in early fall and the onset of winter killing temperatures, leading some to wonder how much benefit they provide. Second, once they winter kill, they provide decreasing cover for the soil as their tissues decay, possibly necessitating additional mulch. Oats and barley are exceptions to the first challenge, growing quickly and establishing well in a short timespan in the cool weather of early fall, but oats, especially, struggle with the second challenge, thinning considerably as winter progresses.

Even better than winter-killing cover crops, there are many other great options for killing cover crops and clearing the soil for planting, which means every great cover crop is also an option for beds.