Every year, more and more people are opening up new ground for gardening, either to create a plot or to expand an existing one. I am a big fan of smaller lawns and bigger gardens, as long as a little space is saved for lawn games like bocce (or croquet). Having planted directly into tilled sod (ground that was previously lawn or pasture) for a season, I have some advice on how to approach this.
For a home-sized garden, a technique called double digging can yield great garden soil. It’s a lot of work, and is not for the faint of heart, but it yields great results. First, dig a trench and remove the sod and top soil. Put it in a wheel barrow or on a tarp, saving it for later. Then use a fork to break up the subsoil. Add some compost. Now dig another trench next to the first one you dug, flipping the soil over, sod down, and placing it in your first trench. Continue until you have had enough. On the last trench, use the soil you set aside from your first trench to finish. The benefits of this technique are both burying the sod and increasing the drainage of the lower levels of soil. Using the forks to break up the inverted layers of topsoil, and then raking, can give you a garden soil that is ready to go.
The tool that is most likely to be used in a home garden, and on lots of farms as well, is the rototiller. Easily rented or borrowed, it’s good at turning fallow land into something approaching a garden. The tines are good at chewing up sod, but they do have a downside. When the bed is being prepped, the tool will work to a certain depth, and then beat on the soil and create a pan, or impervious layer. This pan can get so hard that roots can’t penetrate it. It’s important to keep this in mind, to limit your use of the tiller to when it’s really needed. In a smaller garden, a strong set of garden forks can be effective. Use the forks to rock back and forth in the area you tilled to break up the pan. On the farm scale, a subsoiler or chisel plow can be used to break up the subsoil and promote drainage. I use a rototiller at our farm, but my primary tillage is a chisel plow that I run perpendicularly to the directions of our beds.
The use of the tiller will also chop up the roots of many perennial grasses and weeds and can often lead to more weeds the first year. Before they root back in, take the time to pull them out; it will be much easier to do in the spring. I do advise people to plant bigger spaces between the plants, because the weeds will be more aggressive, and it will be harder to hoe. There are also lots of insects that really like the environment of a sod based soil, and they can cause damage to root crops. Skip the carrots and beets, and stick to greens and fruiting vegetables the first year.
So… If you are going to the trouble of opening up one garden section, consider opening a second plot as well. Use your preferred technique, but then plant a soil building cover crop and manage the second plot for next year’s garden. I like peas and oats with a little vetch thrown in. Lots of organic matter and nitrogen fixation as well. Hard to say no to that.
I hope that 2011 brings a great season for you and your gardening.
All my best,