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Killing with KindnessRemoving a Lawn Without Herbicidesby Philip DickeyFootnoted citations appear at the end of this article. Removing a lawn is like taking up wall to wall carpet in one respect: you're sure to find dirt underneath. But while the dust under a carpet serves no useful purpose--quite the contrary, in fact--the soil under a lawn sustains the life above. There are several reasons to remove all or part of a lawn. One is to make room for other plantings that use less water, are more interesting, and are easier and more fun to maintain. Another is to rennovate a lawn that is weed infested or needs major drainage or soil improvement. Fortunately, there are more ways to remove a lawn than a carpet, and the dirt underneath doesn't have to be vacuumed up. Removing grass to make room for a garden or other plantings can be hard work, especially if the area involved is more than a few square feet. Many experts recommend killing the lawn with an herbicide, an appealingly simple prospect at first, until you start looking at the details. Dressing up in suitably protective clothing and hosing down the yard with chemicals is not my idea of a fun time, especially on a warm day. A few years ago, a neighbor asked me what was the best way to remove her lawn. I suggested renting a sod cutter. She ignored my advice, however, and sprayed the lawn with a weed killer. Some of it died. She sprayed it again. More of it died, but not all. She sprayed a third time. In the end, she rented a sod cutter. This article describes three methods for removing a lawn without using herbicides. Each method has advantages and disadvantages: some methods are quicker, while others are easier. All of them are proven to be effective if done properly. Sod Cutter MethodThis method is more easily used when the ground is soft, in late spring or early summer, just after the rainy season. In this method, the sod layer is sliced off the top, leaving the ground underneath bare and ready to be improved. If you just want to lay out a small garden bed or two, you can use a spade to cut through the sod and lift it out in manageable pieces. For larger jobs, you'll want to rent a sod cutter. The sod that has been removed can be useful if you want to mound up some areas or fill in low spots. I've had good results with this method by turning the sod upside down and layering it until the desired height is reached. Apply some organic fertilizer between each layer and wet them down as you stack them. Then cover the piles with black plastic until they break down. You'll need to remove the plastic from time to time to rewet the sod. The sod should compost in a few months to a year, depending on the temperatures. If you have no use for the sod, you can haul it away to a topsoil or composting facility. Call around to find out who will accept this material. To prepare your new beds for gardening, till if necessary to break up hardpan layers and grade as desired. Add compost to improve the soil, mixing it several inches deep into the existing soil. Save some for mulch after planting, or use wood chips or straw. Multiple-Till and Irrigation MethodIn this method, the sod is covered with soil amendments and then rototilled. The area is watered to stimulate the growth of any weed seeds present, then tilled more shallowly to destroy the sprouted weeds. The process is repeated several times to deplete the seed reserve. Be warned that while this method is pretty effective at killing weeds, it may not completely kill invasive grasses, which get chopped up but can resprout from small pieces. So if you have lots of crabgrass or quackgrass, you may want to use one of the other methods instead.1 Sheet-CompostingThis method is best done in the fall, so that the compost can sit during the winter. The sheet-composting method that some call "lawn lasagne" is great if you have access to large amounts of compostable material and/or compost. Basically, you are going to cover the existing lawn with layers of organic material that will break down and, in the process, soften and kill the grass itself. Some writers suggest breaking up the sod layer first but others do not. There are four basic layers to the lasagne, although numerous variations are possible. This recipe comes from "Sheet Mulching: Soil Building on a Budget."2 The first layer is basically a nitrogen fertilizer. You can use one to three inches of fresh grass clippings or manure, or alternatively apply a nitrogen-rich organic fertilizer. The next layer is the weed barrier, typically up to eight overlapping layers of newspaper or a sheet of cardboard. Be sure that no gaps exist in this layer. Then cover the area with weed-free material such as fall leaves, sawdust, manure, compost, shredded garden trimmings, or whatever you happen to have. One to three inches depth is great, but you can go higher if you have more material. Finally, top it all off with a layer of weed-free mulch such as wood chips, finished compost, or straw. This is partly for appearance and partly to keep leaves in the layer below from blowing around. Be sure to keep the whole thing moist while it breaks down. If you put wood chips on top, don't till these in because they will use up valuable nitrogen. It probably doesn't matter too much exactly how you build your lasagne as long as you put the nitrogen-rich materials on the bottom and everything on top of the barrier is free of weeds. Since this thin, horizontal compost pile doesn't get hot enough to kill weed seeds or plant diseases, be sure not to use diseased plants, seed heads, or aggressive weed material. People have recommended all kinds of strange things for the weed barrier, including burlap, old wool carpeting, and even discarded blue jeans.3 References and Resources
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