Everything You Need to Know About Using Cover Crops in the Garden
If you read my post last week about how to prepare your garden for the fall and winter months, you may have been left scratching your head over what a cover crop actually is - and why you need it.
You see, cover crops are important for your fall vegetable garden in many ways. I’ll tell you why in this article, but for now, know that a good cover crop is exactly what you need to ensure your garden’s success during the next growing season.
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What is a Good Cover Crop for the Garden?
A cover crop is a type of crop that is grown specifically to protect the soil from erosion and degradation. Here is more information:
Common cover crops include grasses, legumes, and brassicas.
Cover crops are often grown between seasons, in order to provide year-round protection for the soil.
One of the main benefits of using cover crops is that they help to add organic matter to the soil, which helps to improve drainage and aeration.
In addition, cover crops can suppress weed growth and help to break up compaction. As a result, they play an important role in maintaining healthy soil conditions.
When choosing a cover crop for your garden, it is important to select a variety that is well-suited to your local climate and soil type. With a little research, you can find a cover crop that will provide the perfect level of protection for your garden.
Here’s a video with even more details and tips on how to help you select the best cover crop for your needs:
What Are Cover Crops?
If you want to grow your garden in a smarter, more economical way, you’ve got to consider using cover crops. This nature-friendly method of providing your plants with fertilizer, protection, disease management, and nutrition between plantings helps reduce the time you need to spend in the garden and is also a sustainable way of boosting your garden’s productivity.
Cover crops are plants that have particularly beneficial qualities. You plant the seeds of these plants between your vegetable sowing, usually sometime between the harvest of your most recent plants and the growth of your plants. These seeds are temporary plantings, meant to serve a purpose for a limited time only.
Next, I’ll tell you why cover crops are so necessary in any gardener’s plot.
How Do Cover Crops Help Your Garden?
Nutrient Replenishment - Green Manure
Implementing certain crops between plantings not only helps preserve nutrients in the garden, but it helps provide new ones, too - and it directs them right to where they are needed.
Not all cover crops will be as good as others at replenishing and renchrinign the soil, but there are cover crops you can choose from to help boost the soil at any time of the year. Somec over crops can retain nutrients all winter, providing all the fertilizers your plants will need come spring.
Plus, when you use a “green manure” like a cover crop as a fertilizer, you won’t be damaging the soil in any way. Lots of gardeners use synthetic fertilizers to boost their soil - in fact, home gardeners provide a shockingly high amount of fertilizer runoff to the water supply each year.
However, not only can synthetic fertilizers pollute the local water supply, but they also throw off the delicate circle of life within your soil, harming the natural fungi, microbes, and bacteria in the soil that your plants so desperately need for good growth.
Plus, green fertilizers like cover crops help balance nutrients as well as supply them, too. Sometimes too much of a good thing can be just that - too much. Nitrogen, for instance, is in high supply in many gardeners that rely on manures to help boost the soil. Too much nitrogen can make the soil too acidic, but a good cover crop can help balance things out.
Mulching for Water Retention and Weed Suppression
Whether it’s too much or too little water or even too many weeds, cover crops can help you out here, too. Not only does a good cover crop prevents the drying of the soil over the winter (the result of erosion) but it also forms a dense mat that can help choke out weeds the following spring.
No more weeding, and less watering during the next dry spell? Call that a win.
Microbe Protection and Erosion Prevention
If you leave the soil of your garden exposed during the long winter months, you’re really doing it a disservice. You should be mulching the soil to help protect it from erosion and the loss of beneficial microbes.
When winter’s harsh elements - be it snow, rain, wind, or sleet - pound the soil, they strip away all the nutrients and structure you've worked so hard to build over the growing season. Many people mulch their gardens throughout the winter for this reason, and that’s a great idea.
However, you don’t need to be spending tons of money or time mulching the soil. It’s helpful, sure, but it’s also laborious. Instead, planting a cover crop will retain moisture and will not only protect the soil from erosion, but it will also provide a safe haven for the beneficial microbes that live within.
Improving Soil Structure
Essentially, there are three ways in which you can improve your soil structure - you can add a mulch, add organic matter (like compost or manure) or to grow cover crops. Cover crops not only mulch and add organic matter to the soil, but they also provide all the other benefits we’ve listed above, making the practice of growing cover crops one of the best things you can do to improve poor soil.
Cover crops help improve your soil through the process of rhizodeposition. As your crop grows, it releases sugars and other substances through their roots into the soil. They release tons of energy into the ground, in some cases going as far as six feet down. These sugars help support the development of beneficial microorganisms who travel with the energy deep down into the ground. And as you already know from the articles I’ve written on natural fertilizers and mulches, those microbes are super important for keeping your soil healthy and productive.
Cover crops can also help you out via the process of bio-drilling. Bio-drilling is the process that occurs when compacted roots “drill” into compacted soil. It’s kind of like aerating your lawn except you are doing it more naturally with plants. There are tons of plants that have the ability to help break through compacted soil, effectively loosening it up for you and making it easier for you to work with.
Preventing Pests
The final benefit that cover crops provide is certainly not one to be overlooked. This is not true of all cover crops, but there are quite a few plants out there that have the ability to destroy and prevent a large number of diseases and pests.
Certain cover crops, when killed and worked slowly back into the soil, release natural phytochemicals that can prevent soil diseases, like those caused by nematodes. Others decrease weeds, which can help remove invasive plants and the insects that thrive among them.
When Should I Plant Cover Crops
Look carefully at the planting requirements for your chosen cover crop. Summer cover crops are usually planted after you have harvested short-season crops - for example, you could plant a summer cover crop after you have harvested your spring snow peas. They’ll help suppress weeds and retain moisture for the areas around the rest of your plants, but it should be noted that some plants, like buckwheat, need to be cut shortly after flowering to prevent receding. Other good summer cover crops include crimson clover and cowpeas.
Winterkill cover crops are usually planted after your garden has finished for the season. These are tough to grow where I live, because the margin between the last harvest and the first killing frost is generally nonexistent.
Because these plants need to be killed by a freezing temperature, I usually don’t have enough time between harvesting that last tomato and giving these crops enough time to grow.
However, if you live in an appropriate area to do so, you might consider field peas, oats, brassicas, or crimson clover - a winter kill cover crop will do great in a warmer area, where you’ll already have a fantastic mulch going come spring.
The last type of cover crop is really my jam. Overwintered cover crops are those that are planted late in the season - even after you’ve harvested the pumpkins and other late fall crops.
These cover crops survive through the winter, offering weed suppression and lots of biomass before you chop them down the next spring. You might want to consider plants like winter rye, hairy vetch, crimson clover, wheat, and triticale for this purpose.
How to Remove Cover Crops in the Spring
So you’ve grown your first ever cover crop - congratulations! Now comes the part that leaves many gardeners scratching their heads - what’s the best way to take one of these densely growing crops down? After all, you’ve got to prepare for spring planting at some point.
You have a few options.
Plowing or Tilling
Traditionally, cover crops have been plowed or tilled under. While there are many benefits to doing this - it’s without a doubt one of the quickest and effective ways at removing a cover crop - there are also several distinct disadvantages.
For one, you’re killing the microbes and diminishing the soil structure that you’ve worked so hard to build. This is a great last-resort option, but I like the other methods that I’ll talk about in a second quite a bit more.
Chickens
Got chickens? Great! You can recruit them to help you turn your cover crops over. Not only will this natural method of composting your over crop help get rid of the standing plants so that you are ready to plant your garden, but your chickens will benefit quite a bit from the extra activity and calories.
If you’re worried about free-ranging them in the garden, whether because they’ll destroy perennials that you have coming up, you’re worried about predators, or you just don’t want them running off, consider pasturing them there in a chicken tractor.
Chopping
Many people chop or pull plants by hand. While chickens are a great option for removing cover crops from the garden, it can take some time - up to a month or more, depending on how large your garden is. Pulling or chopping your cover crop by hand can reduce the amount of time you need to wait.
Black Plastic
If you have some time to kill before you need to plant, laying black plastic down over your cover crop is a great way to get rid of them. Black plastic also helps by warming the soil so that it’s ready to be planted in more quickly. Here’s a good black plastic option for you to consider - I buy several rolls of it every year to put in my garden.
When deciding the best ways in which to remove your cover crop, it’s important that you look at the individual properties of the plant you have chosen. There are some cover crops, like sudex, for instance, that produce residues in the soil that limit the growth of lettuce, tomatoes, and broccoli.
Wheat, oats, and some other cover crops also produce similar allelopathic substances. Therefore, if you chop in these cover crops, you need to wait at least three weeks before planting to allow those substances to diminish.
The Best Cover Crops to Use In Your Garden
Have I convinced you to grow a cover crop yet? If so, great! Here are some of the best cover crops to consider got your garden planning. Just keep in mind that each will grow best in a range of situations and climate, so it’s important to select the one that works best for you.
Buckwheat
Buckwheat grows well during the summer, holding a title all its own as one of the best warm-weather cover crops. When you sow the seeds in damp soil, they germinate and grow quickly in a week, with plants often growing more than two feet high in less than a month! It’s a great option if you need to reclaim portions of the garden that have been choked out by invasives. Buckwheat can be left to die off and be used as a surface mulch, or you can chop the plants into the soil.
Buy some buckwheat seeds here.
Oats
Who doesn't love oats? Oats love cool temperatures and do best in the spring or fall. In spring, you can use oats to provide nutrients and green manure for upcoming plantings in your raised beds. It can also be used in the fall to help provide winter cover after it’s killed off by frost. Oats grow quite quickly, and they’re often planted in conjunction with rye or peas to help outcompete weeds.
Buy some oat seeds here.
Barley
It’s not just for making beer, people (although I like it that way, too). Barley is an excellent cover crop. It grows quickly and is uniquely able to capture the excess nitrogen that is remaining from your summer crops. Unfortunately, it’s not the best if you live in a colder climate - it’s usually winter killed Zones 5 and colder. That being said, if you decide to grow it in a colder climate, you can - just start it earlier. The winner killed barley will protect and mulch the soil throughout the winter.
Buy some barley seeds here.
Hairy Vetch
Hairy vetch is another plant that will need quite a jumpstart before winter - but unlike some of these other more fragile cover crops, it’s hardy to Zone 4. Hairy vetch is one of the best cover crops at improving your soil, as it can also save you some time in the garden later on. You can easily kill hairy vetch when you’re ready to plant, and you can even use it as a mulch after you’ve planted the rest of your crops, too.
Buy some hairy vetch seeds here.
Annual Rye
Annual rye grass produces thick, dense growth that helps limit compaction and loosens up soil. It prefers warm weather but not too warm - it’s best sowed in spring or early summer.
Buy some annual ryegrass seeds here.
Winter Rye
Winter rye helps support nitrogen-fixing legumes and has an intricate root system - it helps prevent nitrogen loss. Alive or dead, winter rye helps prevent weeds and also provides winter cover.
Buy some winter rye seeds here.
Red Clover
Red clover isn’t as great at fixing nitrogen as some other plants, but it is a good choice for wet, shady soils. It is best grown when it is sown with a dense planting of tall cover crops that will provide some shade - but make sure you don’t sow it where the soil is already high in nitrogen. Plant red clover in the spring and fall. It will return in the spring after being winter killed in most areas.
Buy some red clover seeds here.
Alfalfa
Alfalfa is a popular cover crop that grows deep, fixing nitrogen into the soil. It also helps balance out levels of other nutrients, like potassium, phosphorus, and magnesium. It also provides good winter cover as it dies back as perennial to remege in the spring. Because of this, alfalfa is best grown when it can be given two seasons to work its magic. It may not be the best short-term choice, although it can certainly be grown in this way.
Buy some alfalfa seeds here.
Sorghum
Sorghum is another grain grass and is a genus that actually encompasses multiple species, like Sudangrass and Sorghum Sudangrass. These tall, corn-like plants suppress weeds, supply green manure, and even help prevent certain diseases.
Buy some sorghum seeds here.
Less Common Options
Teff
Teff isn’t as popular as some of the other cover crops we’ve mentioned, particularly because it’s very particular as to the climates in which it can grow. A grain native to eastern Africa, this plant loves hot temperatures and prefers very dry weather. Beyond that, it requires little maintenance, growing densely and thickly as it suppresses weeds.
Buy some teff seeds here.
Arugula
Arugula is a popular food crop, beloved for its tangy, spicy leaves, that can also be grown as a cover crop. Best planted in late summer or fall, it produces a dense mat of growth that will cover your beds for the winter and also help bio fumigate your soil.
Buy arugula seeds here.
Brassicas
There are many plants that fall into the Brassicaceae or Cruciferae family, two groups that both fall into the Brassica category. You might consider plants like kale, broccoli, radishes, and cabbage. Not only are these plants great food crops, but they also have superior cover crop capabilities. They are great bio fumigators and also help to aerate the soil.
Buy some brassica seeds here.
Forage Radish
Forage radishes can be eaten, but they also make great cover crops. They are one of the best plants at breaking up rough hard pan and they can also help suppress weeds and destroy disease in the soil, too.
Buy some forage radish seeds here.
What is the Difference Between Legume and Non-Legume Cover Crops?
Cover crops are divided loosely into two categories: non-legumes and legumes. Although I’ve broken down the most common types of cover crops for you above, you may also see them marketed as legumes or non-legumes, which can be confusing for the first-timer.
There are lots of ways to categorize both types of crops, but I’ll give it to you in layman’s terms. Non-legume cover crops preserve the nutrients that might leach out of the soil, as they have fibrous root systems that help reduce soil loss. They also grow vigorously, suppressing weeds. Some examples are buckwheat, grasses (like oats), winter rye, Sudangrass, and barley. There are also several brassicas that are considered non-legumes.
Legumes, on the other hand, have the ability to fix nitrogen into the soil (which is why we like using green beans and peas in the garden, for the record). This category of plants includes crimson clover, cowpeas, hairy vetch, and more.
Both legumes and non-legumes are helpful, contributing organic matter back into the soil, but non-legumes produce more. However, if you decide to till non-legume biomass back into the soil, you will want to do this several weeks before you plant to avoid them tying up nutrients that your crops need.
Are Cover Crops Right For Me?
If you’re looking for a way to improve your soil, suppress weeds - and basically do anything and everything your garden needs for a productive harvest, then cover crops are the way to go. Seeds for most cover crops are inexpensive - they’re going to cost much less, in most cases, than the synthetic fertilizers you like to put on your garden!
Do you use cover crops in your fall garden? If so, which ones? Be sure to let me know in the comments!
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