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Common Composting Questions and Answers

I want to start making compost from my garden waste. Do I need a "starter kit " available at garden centers?

Those new to composting often ask if a compost "maker" or "starter kit " is necessary. These products are made of dormant fungi and bacteria that become active under the right conditions and begin breaking down debris.

These same fungi are already in the garden, present in soil and in finished compost. Adding either of these between your layers of yard waste is enough to inoculate a compost pile and start it working.

Do I have to have to buy a special composting bin in order to compost?

A bin is not necessary in order to compost. A pile can be made on the ground with no enclosure. Minimum pile size is 3' on all sides (27 cubic feet) and maximum size is 5' on all sides (125 cubic feet). This allows enough bulk to heat up properly yet not so much that oxygen is cut off to the center of the pile.

Can I compost black walnut leaves, or will there be problems with the compost related to juglone from the walnut?

In the past, it was recommended that no part of black walnut trees be composted, since the toxin, juglone, may not degrade sufficiently and could injure sensitive plants when the compost is used.

The latest information indicates walnut leaves can be composted; the toxin in the leaves actually degrades in 2 4 weeks depending on the environmental conditions. Walnut leaves can be composted separately and the finished compost tested for toxicity by planting tomato seedlings in it. If juglone is present, the tomato seedlings will wilt.

Wood chips or fresh sawdust from walnut tree pruning is not suggested for use around plants sensitive to walnut; however, composting woody debris for a minimum of 6 months provides a safe mulch even for plants which are sensitive.

How do I know when my compost is ready to use? We built a pile last fall and the compost looks  pretty good right now.

Use only compost that is "finished." Finished compost will be dark and crumbly, have an earthy smell, be within 10 degrees of air temperature, and the pile will be about one-third of its original size. If you use compost as a soil amendment before it is finished, plants in the amended area can develop problems related to nitrogen deficiency or phytotoxicity. To use compost as an amendment, start by turning the garden soil to be amended, then apply compost over the area at the rate of 1 3" and turn it in to a 6" 8" depth (this amounts to about a heaping double handful per square foot).

We renovated  300 square feet of lawn this fall and scraped up a thatch layer that was a half inch thick. Can we compost this thatch, or should we put it out for yard waste collection?

It is possible to compost thatch, though it takes longer than other garden debris to break down. You have a couple of options. One is to pile up the thatch separately; add some soil (there may be some soil still attached to the thatch) or finished compost, and a high nitrogen fertilizer in between the layers of thatch. Water the pile occasionally to keep it moist. It may take 2 years for this to break down. The other option is to mix the thatch pieces in with your leaves and garden debris in your regular compost pile. Keeping the pile moist and turning it occasionally may help the thatch break down more quickly.

I have too many tree leaves to compost, but wonder about shredding them and layering them over the perennial garden for winter protection. Any recommendations?

Applying leaves for winter protection in the perennial garden is a good use. Perennials that are tender, or those that were planted or divided and replanted in late summer or early fall, can benefit from a mulch for winter. Shredding the leaves through a mower or a shredder will prevent them from becoming matted as they get wet. Apply a 3" 6" layer of shredded leaves over the tops of plants to be protected after several hard freezes. This will keep the soil cold and plants in a dormant condition through winter. Usually, this mulch application is made in the first 3 weeks of December or so, but pay attention to weather conditions so you apply it at the correct time.