Cover Cropping in Your Home Garden
As I state on my homepage, one of the main goals of Blooming ‘burbs is to provide an example of “how suburbanites can re-invent suburbia to be a solution to our environmental crisis, rather than a contributor to it.” A main way I do that is with my ecological landscaping practices. For example, I plant a wide variety of plants because biodiversity provides food and habitat for a range of life. I am mostly guided by a goal of protecting pollinator insects and my plant selection reflects that.
I do a number of other things to encourage a healthy garden ecosystem. When I say a “healthy garden,” I mean a garden that is not only productive for both me and the local wildlife, but which is also resilient to various shocks. A healthy garden, for example, is able to withstand pest attacks and drought better than a sickly garden. Makes sense, right?
Good soil fertility is an important foundation of a healthy garden and supports healthy plants. In a well-functioning, self-reinforcing cycle, plants and soils work together to maintain the health of the ecosystem. Plants take up nutrients (like nitrogen and phosphorus) from the soil to develop leaves, stems, flowers, and fruit. When plants, or parts of plants, die, they are decomposed (broken down) by worms and other soil life. Then, plant roots take up the decomposed plants as nutrients and the cycle continues. The soil-plant-nutrient interactions are always moving and changing in ways that you can’t see (unless you’re looking), but on which all life depends.
The nutrient cycle. Credit: https://soil.evs.buffalo.edu/index.php/File:Nutrientsss.png
In “nature” the cycle is tight and nutrients don’t escape, or run off out of the system. They’re constantly cycling and recycling. Contrast this with environments that humans are managing in order to derive some benefit. In agricultural environments, for example, we are growing and removing food, and so nutrients must be added so we can continue using that land in ways that sustain our material needs.
I am growing and removing nutrients as cut flowers. Therefore, I need to have a nutrient management plan to replenish the nutrients I remove. I prefer to build soil fertility, rather than just pour on nutrients with liquid fertilizers. This is because soil fertility has a lot of benefits beyond providing my flowers with nutrients like nitrogen, phosphorus, and potassium. Referred to as soil ‘conditioning’ my management practices enhance soil structure by building long-lasting organic matter, which not only provides nutrients to plants, but also improves water holding capacity, drainage, and workability of soil.
There are a number of ways to condition soil, which you can learn about in books like “Healthy Soils for Sustainable Gardens.” For the reminder of this blog, I’m going to tell you about cover cropping and the crops I used to enhance soil fertility in my garden.
Soil Conditioning Using Cover Crops at Blooming Burbs
Cover crops are planted to provide an ecological benefit to a managed system. I use them to not only build and replenish soil fertility, but also to suppress weeds and keep the soil covered so it isn’t eroded away by wind and rain. I get all my cover crops from Johnny’s.
There are many cover crops to choose from, and the crop you choose should be determined by your particular situation and goals. I’ll give you some specific examples of cover crops I use and why I’ve chosen them.
Buckwheat
Buckwheat (Fagopyrum esculentum) is a fast-growing warm-weather crop that chokes out weeds and suppresses weed seed germination. As a side benefit, it produces flowers that bees love (heard of buckwheat honey?). It has a long taproot so can also break up soil and pull up nutrients from deeper in the soil profile, which makes them available to plants that don’t have such deep roots. This year, I planted buckwheat seed in my raised beds after I harvested and pulled out snapdragons, and in empty areas in my flower beds as a weed management tool. Buckwheat will die back when temperatures fall below freezing. In my case this year, I will have to manually kill it (or “terminate” it) so it doesn’t reseed itself everywhere. This occurs 35 days after planting it. Terminating it is easy! I’ll either weed-wack or crimp it (bend it). I'll be left with a nice layer of decomposing plant matter, and those nutrients will be available to plants next year.
Sudangrass
Sudangrass (Sorghum x drummondii) is another warm season cover crop that will die back when it gets cold, i.e. winterkill. It’s great for suppressing weeds and, like buckwheat, it will pull up and scavenge nutrients from deep in the soil profile. It also performs well in hot dry conditions, which is how things have been here in Michigan this summer.
In the picture above, I’m using it where I had to have a sewer pipe replaced. They had to dig 14 feet down and inevitably used a lot of the subsoil when filling the hole back in. This subsoil is highly acidic, very unworkable due to high clay content, and has virtually no nutrients in it. You can tell it has no organic matter in it, and thus no fertility, by its color, which is tan (notice the small pile of compost I dumped on the left side of the picture to get an idea of what nutrient rich organic matter should look like!). Compare the sudangrass in the foreground and the middleground. This was all planted at the same time, but the sudangrass in the middle is having a hard time growing as indicated by its scrawny height and yellow color, which indicates a lack of nitrogen.
When the sudangrass gets to be about waist-high, I’ll cut it down with a machete so that it forms a layer of mulch that can decompose. It will continue to grow until frost. I’ll throw a thick layer of compost and topsoil on here in September, and in the fall, I’ll mix in some leaves. It’ll take awhile to condition this soil, but we’ll get there!
Peas and Oats
Peas and oats mix or field peas: I grew a lot of peas (Pisum sativum) in the spring in order to bring more nitrogen into the system. Many of us in suburban areas have to deal with clay soils that are both hard to work and lack nutrients. Peas are a nitrogen fixing plant, which means they can capture atmospheric nitrogen and convert it into a form that can be used by other crops. They also have the advantage of being edible and very attractive; I even used pea tendrils in some of my bouquets this spring.
In the next week or so, I’ll be broadcasting the peas and oats mixture all around the garden, which will grow until we get a frost. It will then die back and provide a nice nutrient-rich mulch that I can plant into next spring.
This blog has gotten quite long so I’ll stop there, but I’m happy to share more of my experience in the comments if you have specific questions!
