Farm Your Yard: The Living Soil

Mar 14, 2017

Not to toot my own horn, but I have a great backyard garden. I really can’t take much of the credit for my backyard garden because I am lucky to have amazing soil in my backyard. Without good, living soil, I wouldn’t be much of a gardener.

The quality seed starts you begin now deserve quality soil in the garden. Carrie Hargrove shares her suggestions for soil building on this installment of Farm your Yard.
Credit Columbia Center for Urban Agriculture

When I am outside in my backyard garden putzing around, I am spending as much time tending the soil ecosystem as I am the plants that spring from the ground. My goal as a gardener is to preserve the robust communities of fungi, bacteria, and other helpful creatures that are necessary for my tomatillos, sweet potatoes, and okra to flourish. Good evening Columbia.

You might know someone who had a great garden for a few seasons, only to witness it drop off in productivity after a few years. The garden only producing small, spindly plants growing from rock hard dirt. You might even have experienced this yourself. This slacking off comes because the soil gets depleted of the nutrients and soil-living creatures that must be present for a plant to flourish. A few years of misguided gardening can do that to a soil. Well, I am here to tell you that life is one continuous learning curve, and gardening is certainly no exception. While there is really no instant gratification in gardening, here are some tips that can help re-energize your garden or keep your garden from slacking off in the first place.

Organic farmers have a saying that goes “Don’t feed the plant, feed the soil”. This means that while fertilizing your garden might produce loads of really beautiful plants with lots of fruit and veggies on them, what actually sustains those plants- the soil- is still being depleted by the hungry vegetable plants. Feeding the soils means adding organic matter, minerals, and adjusting the pH so that the soil ecosystem is robust and can give the vegetable plants all they need to grow. Don’t get me wrong, organic farmers and gardeners fertilize their plants too, they just pay attention to the soil as well. Adding organic matter is the most common way that people feed their soil. Organic matter is anything that breaks down. This term “breaking down” actually means that fungi, bacteria, worms and other soil dwelling invertebrates eat the organic matter and then secrete by products that eventually turn into the molecules that plants are able to take in through their roots to help them grow.

This system of breaking down organic matter and turning it into products that plants directly use is an intricate web of relationships and chain reactions that scientists are just beginning to really understand. So, my practical suggestion to all gardeners is just to add things to your soil that will feed the soil. Lots of gardeners use coffee grounds, which is a great way to deal with the by-products of your morning coffee. Shredded leaves from your backyard are another great thing to add. And of course, well made compost is probably the pinnacle example of organic matter for sustaining your garden.

You can make your compost at home, but it can be challenging, I’m not going to sugar coat it. The reason that making compost on a home scale can be challenging for most people is due to the matter of scale. Many homes don’t produce enough food waste to get the compost pile big enough, fast enough for the process to actually begin. Don’t be discouraged though, it might take you several years for your pile to create healthy garden-ready compost, but at least that is better than throwing all of your banana peels in the trash in the meantime, right? A good compost pile has food waste, yard waste (but not twiggy things) and livestock manure. Layer the food waste with the manure and then barely cover those layers with straw, sawdust, or any other carbon-filled substance just enough to stifle the smell- you don’t go overboard on the carbon or the composting process will essentially be shut down. Repeat this process over and over until a year or so later you can take a shovel to the bottom of the pile and scoop out black, crumbly, sweet smelling compost to add to your garden. There are lots and lots of ways to have a successful compost pile, that is just the pattern I use for my home pile with good results.

Any time you add organic matter to your garden, be it compost, coffee grounds or whatever else you’ve got, just sprinkle it on top in a thin layer. A little goes a long way with this stuff. For example, you might add about an inch of compost every fall to your garden to keep the soil communities happy and healthy. Compost is kind of like a sourdough starter, you add a little bit just to get the process going, and then it takes off and grows and grows on its own. Just adding small amounts of high quality compost to your garden will super charge the invertebrates in the springtime and allows them to breed and expand, which your plants will be grateful for.

Also, notice that I said to sprinkle the organic matter on top of the soil. Think about a forest. The leaves that fall and layer the forest floor are the organic matter that is feeding the fungi and invertebrates that help provide the nutrients to the trees and understory shrubs in this particular ecosystem. There is no tilling to incorporate this organic matter into the soil, it is just the slow breaking down of the leaves and those leaf parts working themselves into the soil with the help of insects and other invertebrates, and with the help of these creatures the leaves eventually become the nitrate molecules that the trees take up to grow big and strong. You can mimic this system in your backyard garden. Limiting the amount you till your garden in favor of mimicking this natural process of nutrient cycling, the sturdier your garden will be.

And one last tip: never leave your soil bare. Think about a natural landscape. When do you see vast pieces of land left bare and exposed to the rain, the wind, and the beating sun? Hardly ever. The elements aren’t kind to the physical structure of the soil, and nor are the elements good for the living biota beneath the soil surface. So, if we want to replicate nature in our gardening, we want as many plants covering the surface of the soil as possible and where there is no plant coverage we want to lay down untreated mulch like straw or grass clippings. The mulch protects the soil surface from the pounding rain, the beating sun, thick mulch keeps weeds at bay, helps your garden retain moisture, cools the soil in summer- the list of benefits goes on and on. And of course, that mulch will decompose over time and help feed all of the helpful little creatures that are hidden from view but that are so necessary to gardening.

If I can give any gardener three pieces of advice it would be: to add organic matter to your soil every year, to add that organic matter to the top of your soil instead of incorporating it in with a tiller, and to add a thick layer of mulch to cover all of the soil at all times. These three tricks are something that I have been practicing with my garden for the past 5 years, and it seems to be working like a champ.

Carrie Hargrove is the Director of Urban Farming at the Columbia Center for Urban Agriculture.

Listen for new installments of Farm Your Yard on the second Tuesday of the month on KBIA's Thinking Out Loud, which airs at 6:30 p.m. each Tuesday.