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Gardening Tips: Making and using compost

November 2, 2018 11:38 am Updated: November 2, 2018 11:43 am


Fall is the ideal time to create a compost pile, but keep in mind the compost you start now may not be ready to use until next summer — or maybe not even until 2020.

Right now is when nature provides all the raw materials you will need. Your compost pile can be fenced in or contained by some sort of structure or just allowed to sit free standing.

If you are in an urban or suburban area, you will want, or may be required, to have it in a closed bin because some neighbors may not appreciate having a large pile of decomposing vegetation sitting out in the open next door. Garden centers also sell all sorts of plastic compost containers or bins for making compost.

Constructing a compost pile is a little bit like making lasagna, since you are layering slightly different ingredients over and over.

Start with a layer of fallen leaves that you rake from the lawn. Sugar maple leaves are ideal since they decompose pretty quickly and a 1-foot-thick layer of them is fine for the bottom layer of the pile.

Sugar maple leaves also contain high levels of calcium even after they are dry and this calcium will feed your plants as it enriches your garden soil. Norway maple leaves are almost as good.

If you are using oak leaves, use only a 3-inch layer since they break down very slowly. Oak leaves are high in tannic acid and will not decompose nearly as quickly as other tree species.

It would help if they were first shredded and mixed with other tree leaves. If you don’t have a leaf shredder, you can run them over with your lawnmower and bag the results.

Shredded leaves or shredded vegetable matter of any sort will decompose and turn into compost much quicker than plant material that is intact.

Put a layer of garden refuse on top of the leaf layer using your spent vegetable garden plants such as bean plants, zucchini vines, tomato plants and all the dead or dying annuals from your flower garden.

Large, tough or woody plant materials do not compost well, so avoid using corn stalks, Brussels sprouts stems, ears of corn and woody twigs thicker than your pinky, unless you can shred them first.

A thin layer of fresh, green grass clippings on top of this will supply nitrogen but make it a thin layer since grass clippings also tend to mat up.

Throw a few handfuls of garden soil on top of each layer to supply the microbes that will actually break the material down. No need for a compost starter or any other additives such as lime or fertilizer.

There are literally millions of microbes in even a single tablespoon of soil and, for some reason, all compost ends up with a neutral pH, even if pine needles are used. Remember to think of lasagne as you repeat this layering process over and over until the pile is up to 5 feet high.

You can compost vegetable kitchen or fruit scraps, or even cooked vegetables, but no meat, pasta (no real lasagna) or bread because these may attract rats. Egg shells also add calcium, but they also take a very long time to break down.

Wet the pile down if rain should suddenly become scarce and let nature take its course.

If outdoor temperatures remain above 50 degrees for a couple of weeks the pile should begin to heat up and may produce steam. Ideally, the pile will attain a temperature of about 160 degrees or more, which is hot to enough to pasteurize the compost, but not so hot as to sterilize it.

Buy a long-shafted compost thermometer to see how hot it gets. This compost thermometer also doubles as a soil thermometer and is perhaps one of the most useful garden tools I own.

Temperatures around 160 degrees should kill all weed seeds and disease spores. After it cools down, turn the pile with a pitchfork to aerate it. It may heat up again after you do this.

Compost piles that fail to heat up can usually be jump started by turning again. Compost is considered “finished” when you cannot distinguish the original materials that went into it.

Since different materials decompose at different rates, it is usually necessary to sift it through some sort of screen such as chicken wire. The plant materials that have not completely broken down can be returned to the pile for the next cycle.

Reach Bob Beyfuss at