Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

How do I compost leaves?

The problem with leaves is what to do with them. Left on the lawn, they smother the grass. Left in the flower beds, they mat down in a wet mass, hampering spring flower emergence. A better place for them is in the compost pile. If you don't have one, build one. Leaves are the nucleus to making an organic, crumbly material that can turn a poor clay soil into a rich productive soil and a compacted soil into a well aerated soil. In its most usable state, this organic material is called compost and the process of leaf composting is easy and it avoids the bagging situation that adversely impacts our landfills.

There are some simple rules to leaf composting. First, rake the leaves into a pile in a corner of the yard or place them into some kind of bin, made of wood, wire or both. The idea of making a pile is more than just getting them out of the way and confined to a corner of the yard. In a pile, leaves will begin to decompose by themselves as the bacteria and fungi start to multiply. The process of degradation generates heat which serves to speed the breakdown. Piles constructed too small lose heat rapidly and slow decomposition. Instead, construct a pile of the proper size that insulates the top and sides. Loose piles go flat after a short time and the insulating effect is quickly lost. A bin keeps the material heaped up. One measuring 3 X 3 X 3 feet constructed of hardware cloth and wood is ideal to hold heat and will take up very little room on the property.

To begin, add about 6 cups of 10-10-10 garden fertilizer per cubic yard of leaves along with enough water to wet the pile to the consistency of a damp sponge. Nitrogen is the most natural limiting factor to bacterial growth and its addition will boost the decomposition process tremendously. The center of a pile may reach 120oF or more in a couple days. If turned after it has begun to cool down and kept wet, the decomposition will continue eventually producing a good leaf mulch that can be used around plants as a wonderful insulator to temperature extremes and as a buffer to moisture fluctuations.

If you have plenty of time and patience, compost happens by itself. Compost piles constructed of raked-up leaves may take months to work down into a finely graded compost. One way to speed the process up is to shred the leaves prior to making a pile. The smaller pieces produced will decompose much faster. Today, leaf shredders are easy to find, but cost a minimum of $100-200. As an alternative, you can either rent one or use your bagging lawn mower to chop the material. If you have a considerable amount of leaves to rake and dispose of, shredding is key to reducing the volume of material and generating a quick compost.

The final factor beyond nitrogen, water and pile size, is air. Sufficient air in the pile encourages microbial growth and speeds decomposition. We have all had the experience of smelling a mass of wet grass clippings. This is an example of a compost pile without air and one reason why clippings, if collected, need to be worked into a compost pile along with other courser materials, like leaves. Turn the leaf pile periodically to supply air. Do this just after the pile has completed a heating cycle. With the addition of a little nitrogen and moisture at the same time, the heap will continue its decomposition course.

Composting leaves solely is a slight twist to the total story about composting yard waste. Good gardeners recognize that composting takes place all year long and involves not only leaves, but green materials like grass clippings, weeds, spend flowers and other vegetable materials. Constructing layers of browns and greens can produce an organized pile that requires minimal attention.