For as long as we’ve been gardening, my countryside travels have been marked by an ever-scanning eye in search of hay mulch. We drop pins on the map and later knock on doors to see if farmers are looking to get rid of old, half-rotten bales that can be used as a weed suppressant and build organic matter in our gardens.
Hay mulch has served us well for the past 15 years of vegetable gardening. But free, or cheap, bales are becoming difficult to find, and the horror stories of Aminopyralid (herbicide) contamination, which is so pervasive it survives the ruminant's digestive system and the composting process before poisoning vegetation in the garden, have prompted a search for alternatives.
Cover crops have proven to be an excellent choice.
So far, we’ve been able to still find unsprayed hay. However, not knowing how soon the well will dry up, we’ve armed ourselves with the knowledge to use cover crops as a replacement, small-scale, self-sufficient source of garden mulch.
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Benefits of Garden Cover Crops
The benefits of cover crops in the garden extend far beyond our primary goals for their use. There are many reasons to incorporate them into your garden.
Prevent erosion and topsoil loss - Root systems left in place will retain topsoil, preserving precious organic matter and soil nutrients.
Improve and preserve soil structure - Especially in a raised bed or no-till garden, root systems of cover crops prevent compaction and provide natural aeration when they decompose. Some covers, such as radishes and turnips, go even further in aerating soil.
Increase biodiversity - No matter the cover crop, you’ll be amazed at the insect life they encourage, including beneficial insects and pollinators. They are the preferred home of garden ladybugs, and golden yellow eggs dot the blades of grass throughout the bed. With so much life above the soil, we can readily imagine how much more abundant it is in the unseen world beneath the earth.
Increase organic matter - Soil testing in our gardens has shown that, while not as beneficial as hay mulch in increasing organic matter, cover crops will still serve that purpose. This year both of our gardens saw an increase, but it was 5% higher in the garden with hay mulch. However, the increase in organic matter significantly increased the Total Exchange Capacity (which affects water retention and the ability of nutrients to be transported and then taken up into the plants) by an average of 30% in each garden in just one year!
Balance the soil nutrients - When incorporated before going to seed, cover crops add nutrients to your soil, increasing the nutritional value of your food.
Support and feed the soil food web - Beneath your soil is an army of tiny, even microscopic, critters improving soil and transporting nutrients between plant roots. Decomposing cover crops and their roots create a welcoming environment for them and help their populations to thrive.
Retain soil moisture - Along with retaining topsoil, the root systems from cover crops will conserve moisture in the garden. This benefit will continue even after you drop the crop to use as mulch.
Living mulch - In some beds, consider using cover crops as living mulch. Nitrogen-fixing (if the seed is inoculated) Crimson Clover is the perfect understory layer for tall, heavy-feeding crops such as corn, tomatoes, or trellised cucumbers and melons.
Chop & drop mulch- In beds where a living mulch would be inappropriate, cover crops can be chopped or crimped and left in place to cover the soil. Ultimately, this is far less work than importing and spreading other sources of mulch.
Supplemental animal feed - While it’s not likely most of us will have enough room to grow enough cover crops to feed our livestock, they can be used as supplemental feed, adding diversity to the diets of poultry chicks, or as an easily harvestable food source for rabbits.
Types of Cover Crops to Consider
While a wide variety of options are available to use as cover crops, not all are suitable or economical for home gardeners. To get the most bang for your buck with the least amount of work, consider planting a few of these simple, inexpensive cover crops.
Oats are an excellent choice for a resting bed that won’t be replanted before winter. After a few freezes the oats die off and the bed will be plantable with little work in the spring. Family herbalists can also harvest the blades as they grow for nutritive oat straw in tea blends or let a small part of the bed go to seed to harvest as milky oats. Oats are often mixed with peas to add diversity, however, we’ve not noticed that it’s at a high enough ratio to increase the benefits over oats alone. If you do choose to grow an oats + peas mix, the pea greens & shoots can be foraged for adding to your meals or salads. Adding in some tillage radishes to the oats + peas blend makes a nice combination, boosting the benefits to add in aerated soil.
Winter Rye is appropriate when you want the cover crop to survive over winter. For example, we use it in our “after danger of frost” beds. In April and May, we can focus on spring crops without needing to manage weeds in the other beds that won’t be planted until the last week of May.
Tillage Radishes or Turnips
In areas of compaction or in an overwintering mix, these root cover crops will decompose in the spring after soil expands and contracts during the freeze/thaw cycle, improving tilth. If planted later, the root doesn’t have as much of a chance to grow and the plants will go to seed in the spring providing one of the earliest nectar sources for honeybees. The earthworms love the decomposing root for these cover crops.
Buckwheat is best used when you would like to mine up phosphorus to be available for your plants. Be sure to harvest before going to seed or the plant will start using up the phosphorus.
It’s a fine line if your goal is to invite pollinators and beneficial insects to the garden. Watch the crop closely after flowering and cut it down as the blooms begin to fade. Unlike grass covers, buckwheat is easy to kill by cutting or trampling. If you choose to leave a few plants, they easily reseed.
Crimson clover functions well as a living mulch. When inoculated, it fixes nitrogen in the soil. Blossoms invite beneficial insects and pollinators and it will likely be winter-killed in northern climates. Unfortunately, it is one of the more expensive cover crops available.
Due to its biomass, sudangrass may be an excellent supplemental feed for your livestock or as a hay mulch replacement. For the same reason, it is not always appropriate in many small-scale gardens. It can grow up to 12’ tall! We are experimenting with it in fallow beds this year to be used as a fall mulch.
How to Use Cover Crops in a Homestead Garden
There are three easy ways to incorporate cover crops into a garden, even no-till systems.
Protect your Garden with a Winter Cover
In the fall, as crops are removed, sow either oats or winter rye in the bed and scratch the surface with a hoe to incorporate them into the soil. Both germinate quickly.
If there is more than a month before a freeze and you want to plant the bed early in spring, choose oats. If there are only days before a freeze and you do not want to plant seeds until after the danger of frost in the spring, choose winter rye. Winter rye works well in beds where you will transplant taller crops, such as tomatoes and peppers, the next season. If the bed doesn’t meet the criteria, consider using hay mulch. Otherwise, you may not get the optimal benefits and it can create too much work during a hectic spring sowing season. Planning your cover crops to coordinate with spring planting is another reason for a multi-year crop rotation plan.
Living Mulch for Easy Weed-Free Gardens
Hay mulch may need to be replaced throughout the season and bare beds are certainly anything but weed-free, but with a living mulch, you only need to weed until the cover crop is established and forget it the rest of the year! Crimson clover is appropriate for any crop that grows taller than 12”.
Another choice to consider is winter rye. While not as carefree as crimson clover, we grew tomatoes, peppers, and summer squash in winter rye and it worked well. To do so, completely remove the rye in a circle around the transplant. Rye grows between the plants. A few times throughout the growing season, use a sickle to “mow” the grass and lay it down as mulch. With each “mowing,” there may be successively less rye growing. By the end of the year, it may not need to be managed further.
One time, we had two rows of summer squash - one in the rye and one in hay mulch - and there was no pest pressure in the cover-cropped row!
Rejuvenate Fallow Beds
There are many reasons to consider rotating fallow beds throughout your garden. These can be planted with a cover crop to rejuvenate the bed. The bed will need to be weeded once before sowing, then planted, and monitored for stray weeds. Before the crop goes to seed, it will need to be killed and replanted if there is a growing season left. Consider oats and peas mix, followed by buckwheat, and then overwinter rye for a full range of benefits.
This works well for beds that are harvested early too and will not be replanted, such as peas, spring greens, and garlic. Buckwheat is perfect for following these crops. It has a short growing season and will be ready to plant again for a winter cover.
Break up Hard Ground
Turnips and tillage radishes, also known as Daikon radishes can be used to break up heavy clay or compacted soils. They could also be considered an inexpensive alternative to using a broad fork when preparing a bed for root crops, particularly carrots or parsnips. These cover crops produce large roots that penetrate deep into the soil, leaving it loose and ready for the carrot’s long tap roots to grow. Plant the cover crop in the fall, at least 4 weeks before the ground freezes, to give the roots a chance to grow large and the plant to go through most of its life cycle. In the late winter, the freeze/thaw cycle will rot the roots and usually leave only small, manageable pieces of vegetation by the time you’re ready to plant in the late spring.
Bonus- Daikon radishes are good eating! They are crispy, juicy, and sweeter than a typical garden radish. So don’t hesitate to let them pull double duty in the fall garden as a cover crop and for the occasional harvest.
When to Plant Cover Crops
While there is some flexibility, knowing when to plant your cover crops is critical to helping you achieve your goals.
Oats- spring, summer
Buckwheat- spring, summer
Winter Rye- spring, summer, fall
Crimson clover- spring
Tillage Radishes- spring, fall
Sudan grass- summer
Here is an example of how one could incorporate cover crops in their garden in a year:
Sow in fall for spring growth or to use as chop & drop mulch- winter rye
Use a tarp to kill off at least two weeks before the last frost prior to preparing a seedbed. For a chop and drop mulch, transplant seedlings directly into the mulch then use a sickle to cut the rye close to the ground and lay it around the seedlings.
Sow in fall for winter kill- oats, peas, tillage radishes (singly or in combination)
Clean out the crop residue after harvest, slightly break up the ground with a hoe, sow the cover crop, and tamp it down or use the hoe to scuffle them into the soil. Sow these crops at least a month before the first frost so they are able to grow enough to provide benefits. In the spring, the ground should be ready to plant.
Sow in spring- oats + peas
Plant these crops as you would the winter rye just described. Spring sown oats + peas will need to be killed off with a tarp or sickle prior to seed heads developing.
Sow in summer- buckwheat (especially following an early vegetable harvest like garlic or beans or early spring crops)
Buckwheat grows easily when scattered over loose soil. Scuffling the seed in helps for greater germination. Terminating the plants, whether before or after flowering, depending on your goals, is very simple: Use a scythe to cut, large branch to whip, or even your feet to trample the plants. This level of destruction is the perfect job for little boys, imagining their victory as they conquer the tear down their enemies.
Fallow beds- crimson clover
Innoculate crimson clover to enable nitrogen fixation, a process which works best if they are allowed to grow all season. By the fall, they will bloom with lovely flowers which attract pollinators. Crimson clover will not winter kill and will require a tarp to kill it off or need the ground to be turned over prior to planting. I love to use this cover crop to supplement feed for the bunnies.
Cover Crops Caveat
The grass isn’t always greener and cover crops are no exception. Learning how to kill cover crops has been a challenge. In farming and market garden systems, cover crops are either tilled under or expensive machines, such as flail mowers or roller/crimpers, are used to pinch the blades of grass at two points, which kills the grass above the crimp. In a tilling system, this is no issue but it presents a problem to the many converting to no-till gardens.
Regardless of methods, if your goal is to use the cover crops as mulch, you wouldn’t want to till the crop under. We did not find weed whacking and DIY board crimpers, which are the tools most commonly promoted for home scale use, or hand crimping to be effective. A scythe was difficult to swing in our narrow paths. It simply knocked down the plants. With all these methods, the plants regrew later.
We had great success with a sickle. While it was laborious, it didn’t take as long as expected for a 50’ row. Because the cut was able to be made so low on the plant, there was no regrowth and the bed was immediately ready for transplanting. If the bed is to be seeded after cutting, consider a black fabric mulch for a couple of weeks to accelerate residue decomposition and create a workable seedbed.
While managing crop removal can be a task until you find a system that works for you, we all know how much work pulling or hoeing weeds can be. Why not give cover crops a try in your garden this year and see how they decrease your workload while improving your garden?
Plow in Hope is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.
Thanks for the read. I thought you might be interested to know that we've been experimenting with peppergrass, the winter weed, as an early season cover crop. The seeds are easy to gather, we sow them after fall harvest, and the plants fade away early enough without much labor or encouragement. It gives us something green to eat extra early too.
My father-in-law does hay, in Pennsylvania, so I’m not sure that will help us in Tennessee once we are true homesteaders. We are still in Virginia, and on the “we may be moving there in the next five years” plan. Helpful information to keep in my back pocket, thank you.