By Jean English
Looking for free “fertilizer” for your lawn or garden? Look to leaves!
Leaves that drop in the fall can supply all the nutrients needed in a vegetable garden. They’ll even supply a wider range of essential nutrients than a bag of 10-10-10 synthetic fertilizer, because tree roots draw over a dozen plant nutrients up from the soil and deposit them in leaves. Bags of synthetic fertilizer, on the other hand, often contain just three essential plant nutrients: nitrogen, phosphorus and potassium.
|Photo by Jean English.|
So, instead of thinking of leaves as waste that needs to go “away,” think of your yard as a source of nutrients, a green manure crop, for your garden.
The University of Florida found that “good yields of such crops as cucumbers, tomato and greens can be expected after 2 to 3 years of applications of at least 20 tons [of oak leaves] per acre annually.” That’s a little under 1 pound per square foot per year.
Some people worry that adding leaves to the garden will tie up nitrogen that crop plants need. This won’t be a problem if you add leaves as a mulch in the fall (especially if you’ve shredded the leaves by running over them with a lawnmower), so that soil organisms and weather move them into the soil slowly. Also, including grass clippings with leaves adds nitrogen to the mix, further reducing the chance of nitrogen deficiency, as does mulching the garden with additional grass clippings throughout the summer.
If you don’t have a garden to receive leaves, or you don’t have a lawn mower that catches clippings and leaves, just leave the leaves on the lawn, mowing them a few times during the fall to shred them. Denise Ellsworth of Ohio State University Extension writes, “Research has shown that lawns can absorb many pounds of shredded leaves with no detrimental effects.” She says that Purdue researchers mowed 2 tons of leaves per acre into turf grass annually for five years. They saw no increase in disease or weed problems and no pH or nutrient-availability issues. Microbial activity did increase—a sign of improved soil quality. (“Leaves benefit gardens as compost and mulch,” Akron Beacon Journal, Nov. 10, 2007).
Decomposing leaves improve soil structure so that it absorbs more moisture during rains and holds that moisture better during dry spells. Your lawn will stay greener longer in the summer.
If you don’t want to mow and shred leaves, you can rake them into compost piles and make leaf mold—a good substitute for peat moss in the garden and in potting mixes.
This article is provided by the Maine Organic Farmers and Gardeners Association (MOFGA), PO Box 170, Unity, ME 04988; 207-568-4142; [email protected]; www.mofga.org. Joining MOFGA helps support and promote organic farming and gardening in Maine and helps Maine consumers enjoy more healthful, Maine-grown food. Copyright 2008. If you reprint this article, please include this reference, and please let us know that you have reprinted. Thanks!