Turn fall leaves into spring garden food

Last week I wrote about using chopped leaves as mulch. Mulch, you will recall, is something used to protect plants and bare ground. I talked about using leaves for mulch, because they will continue to break down and enrich the soil.

But there is only so much mulch a yard can use at a time, especially if you have lots of trees. So today we'll go a step further and talk about making compost with the remaining leaves. That compost can, in turn, be incorporated into the soil next spring to feed it. And if you feed your soil well, you will have a good garden. In fact, this is probably the most important step for a successful garden.

First, I want to make it clear that I will be describing a simple leaf-and-grass-clippings compost. This will not include directions for composting your kitchen waste or rabbit and chicken manure or weeds. That is another topic for another day because it requires a slightly different method.

Sometimes referred to as the "University of California Method," or sheet composting, you can do this as a pile on the ground. Or, to keep it neater and more controlled, make a circle of wire fencing about 3 or 4 feet in diameter. Stand a piece of perforated PVC pipe in the center to allow more air circulation in the center of the bin. You might also use a commercial compost bin or tumbler.

Leaves abound in trace elements, and the main thing to remember is that they must be chopped or shredded so as to expose more surface, thus making it easier for them to break down into compost. You can accomplish this by running over them with a lawnmower or putting them through a leaf shredder. Dump a generous layer of chopped leaves into your bin or on the ground.

Next, add a layer of grass clippings or other source of nitrogen, such as alfalfa meal, blood meal, well-rotted manure or cottonseed meal. The proportion of leaves to nitrogen material is important. Two parts leaves to one part grass clippings works well. Adding a shovelful or two of soil or previously-made compost is helpful to get the decomposition process started.

Add enough water to make the mixture feel like a damp, but not soggy, sponge. Then repeat the layering process until the pile is at least 3 feet deep. This is necessary to keep the pile hot enough to decompose the materials. Cover the pile with plastic for four or five days. Remove it and give the pile a good stir. Air must be incorporated into the mixture, as it is needed for the microbial activity that is turning your leaves and grass into compost.

Cover the pile again. Check back in a couple of weeks, and I think you will be amazed at how much the pile has gone down, which indicates that it's decomposing.

The pile should smell earthy and rich. If it stinks, there is too much nitrogen, and you may be able to correct that by adding more brown, or carbon, material (leaves). If it is not decomposing, it means you don't have enough nitrogen, or green material, or it is too dry. These adjustments can usually be made by mixing in the needed material.

Next spring, when you incorporate this compost into your garden soil, it will all but jump for joy.

Coming up: From 7 to 9 p.m. on Thursday, Dec. 2, view a film on "Ruth Stout: The Original Organic Gardener," followed by a discussion of her No Dig/No Work method. The class will be held at the Southern Oregon Research and Extension Center, 569 Hanley Road in Central Point. The cost is $5. Call 541-776-7371.

Carol Oneal is a past president of the OSU Jackson County Master Gardeners Association. E-mail her at diggit1225@gmail.com.

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