Cover crops are so important for improving soil and protecting the environment that it’s public policy in Maryland to use federal funding to subsidize farmers to plant them. Nearly ½ a million acres across the state are enrolled in Maryland’s Cover Crop Program. Cover crops protect Maryland’s farm fields from soil loss over the winter and scavenge the soil for the fertilizer nutrients that weren’t used by corn and soybean crops and might have moved into groundwater and surface water.
Cover crops are typically planted from late August through October and include grasses like winter rye, winter wheat, barley, and oats and legumes like crimson clover and hairy vetch. Plants in the legume family, together with special soil bacteria, transform nitrogen from air into a plant-available form. Tillage radish (a type of daikon radish) and other plants are also grown as cover crops.
Cover crops improve soil health and help make soils more resilient to the climate crisis. They
increase soil organic matter and carbon sequestration by feeding soil microbes with sugars and other root exudates
improve soil structure and the strength of soil aggregates which lowers erosion risks
increase water holding capacity which allows crops to withstand drought better
Cover crops use the sun’s energy (when food crops aren’t growing) to produce biomass- roots, shoots, and leaves. The cover crops are killed in the spring. Nutrients in the decomposing plants are eventually available for uptake by the roots of the vegetables and flowers we plant. This reduces the need for synthetic fertilizers, whose production requires fossil fuels.
What’s good for ag soils is also good for garden soils! 2022 is the Year of Soil Health for Grow It Eat It, the food gardening program of the UME Master Gardener program. This infographic by Jean Burchfield introduces the idea of planting cover crops, a key practice in building healthy soils:
There is a whole group of plants in the Leguminosae (a.k.a Fabaceae) plant family and are referred to as legumes, a word that many people may have heard but may not know the special details about. Have you ever heard that legumes make their own nitrogen or that they are plants that never need nitrogen fertilizer? Well, both those statements are true!
Healthy soil can sustain plant growth, prevent environmental damage, mitigate stormwater runoff, and help recharge and clean groundwater.
Soil type is probably not something that people consider when they move to a new property, so it reminds me of the statement “you get what you get and you don’t throw a fit”. However, it is no secret that soils are not all created equally in their ability to grow plants. To make matters worse, the soil is constantly being manipulated to accommodate our needs. When infrastructure like roads and buildings are constructed soil is moved and in many instances, there may not be any native soil profiles still intact on the property. Often a small layer of topsoil is put back onto the landscape after construction and regrading of the land, but there is no guarantee that it was the topsoil found there before construction began. Once the excavation is completed there is no going back. This article from Penn State Extension, Can Disturbed Soils Grow Healthy Landscape? is a great read. If you suspect that the soil you are planting vegetables into has been hauled in from another location, it is wise to get the soil tested for lead content. Some labs also test for heavy metals like arsenic (As), cadmium (Cd), and chromium (Cr), which can be found in soils on old industrial sites.
Soil is the gift that can keep giving, but there are some management practices that can help improve all soils. The physical, chemical and biological processes of soil are all interconnected. If you want to learn more about your own soil, I recommend the Kansas State publication that walks you through the steps to Estimate Soil Texture by Feel. Knowing the soil texture in your garden is one piece of the soil puzzle.
Soil organic matter increases water holding capacity, improves water infiltration, serves as a source of micro and macronutrients, and provides large particles for micro and macroorganisms to break down. Soils that are high in clay or sand can benefit from the addition of organic matter, which comes from anything that was once alive. Macro and microorganisms help to break down organic matter and release nutrients into the soil. There are many forms of organic matter that include compost, plant material, livestock waste, humus or leaf litter.
Cover crops are another way to improve your soil because they capture excess nutrients that are left over from the growing season and prevent the nutrients from becoming environmental pollutants. Cover crops also prevent soil erosion from wind and rain during the late fall, winter, and early spring seasons when weather is not appropriate for most vegetable or agricultural crops. Once cover crops are terminated they can be plowed into the soil and add organic matter. This is called green manure. I’ve found that in my own garden, cover crops can also help prevent weeds from growing. Some cover crops like forage radishes die and create natural pathways through the soil for water to flow.
Other management practices to help your soil include regular soil testing to monitor any changes and keep the soil pH in the correct range for your desired plants. Limit soil compaction by keeping vehicles, equipment, and even people from walking through gardens, especially when the soil is wet. At the very least, I think the best practice for improving and keeping your soil healthy is to leave it alone as much as possible, keep it covered with plants that are not invasive, and let the natural processes of the Earth work together to benefit the soil.
By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland. Read more posts by Ashley.
This year, the University of Maryland Extension Master Gardener Grow It Eat It Program celebrates the resource that supports all life on earth – soil! Look for soil education programs offered by your local Master Gardener program, and visit the Home & Garden Information Center website for more information about soil health.
Wheat is in the news this year (recall export restrictions from Ukraine and India). We don’t usually think of wheat as a home garden crop, but it does grow well in this area.
In 2017, 2019, and 2021 I planted wheat on a small section of my community garden plot in Gaithersburg. I planted hard red winter wheat in late October in a 5′ x 7′ plot in full sun. Winter wheat needs about 8-10 weeks of growth before the ground freezes, at which time it should be about 5-6″ tall. Rows can be 6″ apart, so it also serves as a cover crop over the winter. I surrounded it with a rabbit barrier of chicken wire.
In spring, the wheat grew to about 4′ in height and began to form kernels in May, and I encountered my first challenge – birds. Sparrows swooped in and started eating the young seed heads. Recycling some cicada netting over the top and draping it over the chicken-wire fence surrounding the wheat was effective for a while, but when the stalks began to mature and dry, the pesky little sparrows found ways to get in. I had to use clothespins to secure the netting to the chicken wire.
Harvest time was in early June. I found an old scythe in my community garden toolshed, sharpened it in my kitchen, and cut the wheat stalks about 18″ long. After gathering them into sheaves and tying each bundle with a shoestring, I hung them to dry for a couple of weeks. The second challenge was threshing.
There are lots of ideas on the internet for threshing; that is, removing the grain from the stalks. An ancient no-machinery method is to walk on the wheat heads, or hitch your animals to a circular contraption and have them walk around and around over it. We preferred a more sanitary way. Other methods repurpose bicycles and other machinery to release the grains. Or you can beat the stalks against the inside of a bucket. In my case, I put my husband to work bashing a pillowcase of wheat heads against the floor and then stomping on the pillowcase.
Next comes winnowing. I set a simple household fan on the kitchen counter and poured the wheat berries into another bowl in front of the fan. The heavy kernels dropped into the new bowl and the chaff, which was much lighter, blew away. (This required a major cleanup of my kitchen. It could definitely be done outdoors!)
To preserve the wheat berries, I packed them into jars and plastic containers and stuffed what I could into the freezer. When we are ready to make bread, I thaw a jar of the wheat and grind it with a NutriMill electric grain grinder. That does an excellent job, and I make bread using half whole wheat and half good quality white bread flour. Pass the raspberry jam!
Linda Davis is a Master Gardener living in Gaithersburg, Maryland. She completed the Master Gardener course in Virginia in 1997.
Soils, plants, and animals are highly interdependent. Soils support and feed microbes and plants which feed animals. Dead plants and soil critters replenish the soils’ organic matter and nutrient supply, completing the cycle. We know that healthy soils produce healthy plants. Many experts believe that improving soil health is the most important thing we can do to make our farms and gardens more climate-resilient.
Why are soils so important in dealing with climate change?
They store huge amounts of carbon in the form of carbon dioxide (CO2) and organic matter, all of the living, dead, and decomposing plants, microbes, and animals that live in soil. Carbon dioxide is the primary greenhouse gas that is warming the planet. Deforestation, the removal of wetlands and peatlands, and soil tillage cause the release of huge amounts of CO2. Warmer temperatures cause more rapid organic matter decomposition and turnover, especially if soils are tilled and uncovered.
Climate change is causing mid-Atlantic weather to be warmer and wetter with more extreme weather events, including periodic drought. This increases the risk of soil erosion and nutrient run-off from intense rainfall, and the risk of plant stress from excessively wet or dry soils.
After a fun year of building support structures and growing really long squash, it was time to wind down the garden. Our first baby was born (thank you, thank you), and we had no further bandwidth or ambition to continue with cool-season crops, so I decided to pack up the support gear, rip out the remaining plants that were producing but slowing down, start a compost pile with the remains, and plant cover crops in the beds.
Packing it up
My big trellis used for the Tromboncino squash and the one made from part of a fencing panel used for tomatoes both folded up and packed away nicely in this outdoor storage area attached to my house. I’m happy with my designs, as I didn’t want permanent structures out in the garden getting weathered, and I didn’t want them to take up a lot of space in storage. These will be easy to set up next year again. The only thing I will do differently in the future is to use something stronger than twine to string on the trellis and hold up tomatoes with tomato clips. A lot of the twine that was under pressure from crops eventually snapped and needed replacing.
Rip it, chop it, bin it
We were going to have such a volume of garden waste this year, I decided to start a compost bin. This should give us a head start on the new layer of compost (previously all store-bought) we add to the raised beds each year. Pretty much all we have to do is throw this stuff in a bin and wait, as we are doing passive composting that is slow but requires very little attention.
I bought a cheap compost bin online; this one is just a sheet of black plastic with holes that you form into a vertical cylinder and throw your stuff into.
I ripped up our squash, watermelon, and tomato plants, wheelbarrowed ’em over to the compost bin in our back yard, stabbed at the pile with a shovel and buzzed it with my string trimmer for a while to chop it up a bit. Then I shoveled it all into the bin, attempting to mix up the types of plants in there somewhat uniformly.
Once leaves fall, I’ll drop some leaves that have been shredded by the mower into there as well.
I know you can drop food waste like fruit and vegetable scraps into compost, but I’m not sure we are going bother making the trip from the kitchen to backyard with a couple banana peels since that’s just not a lot of volume to make a difference for our intended purpose.
We will need to turn the pile a couple times in the next year to aid decomposition, but other than that, this is hands off. I’m looking forward to seeing what we get at the beginning of next growing season to start our summer vegetable garden again.
Cover crops for our raised bed garden to make it through the winter
I know it is good to protect my soil from erosion and add a layer of compostable material on the top over the winter. Last year, I had read that a layer of mulched leaves is good to place into raised beds, but when I did that, I found that much of it quickly blew away.
This year, I decided to plant crimson clover, a cover crop.
Cover crops, also known as green manures, are an excellent tool for vegetable gardeners, especially where manures and compost are unavailable. They lessen soil erosion during the winter, add organic material when turned under in the spring, improve soil quality, and add valuable nutrients.
With a couple inexpensive packets of crimson clover, I sprinkled the seeds over the now empty raised beds, raked a bit to cover them lightly with soil, and then watered the soil most days. I could see sprouts in a week or so.
The clover will add a layer of protection over the winter, and then nitrogen and nutrients in April when I cut it down with a string trimmer and then turn over the soil.
Sounds easy enough. I’m all about lower-effort gardening!
This post is modified from an article originally published in The Delmarva Farmer (2/13/2018)
Most people would probably be surprised to know that bacterial cells outnumber human cells in our bodies by 10-to-1 and that just one teaspoon of healthy soil contains more than 1 billion bacteria and fungi (microbes for short). Yuck, right? Well, not exactly.
Microbes have gotten a bad rap because the small fraction of bacteria and fungi that cause disease get all the attention. In fact, most microbes are friendly, and neither humans nor plants can live without them.
Although the chemical and physical properties of soil have dominated discussion (and soil testing) in the past, the focus is now changing as soil is recognized as a living ecosystem. With this change, it is becoming clear that sustained agricultural productivity requires farming practices that protect the soil and increase the diversity of life underground. Home gardeners can also benefit from gardening strategies that protect and promote the living things in their garden soil.