How to Neutralize the Odor of Rotten Plant Material

Grass clippings, fallen leaves and compost piles all have something in common: they are made up of dead plant material. When plants die, bacteria flourish and begin to break down the leaves, flowers and fruits, turning the plant material back into soil. This process, while creating a useful soil additive, can emit a variety of odors from rotten to earthy, depending on conditions. With a few simple techniques, you can make sure that your yard trimmings and kitchen scraps decompose quickly and with little to no odor, providing you with rich organic mulch for your yard or garden.

Straw

Sawdust

Pitchfork or rotating compost bin

Prepared mulch

Powdered limestone

Use a variety of plant material to maintain a healthy balance in your compost. Grass clippings will begin decomposing quickly, and with a very strong odor. To minimize this smell, layer grass with leaves, straw or sawdust, and kitchen scraps so that your compost has an even mix of materials. Also, keep your compost piles to a manageable size, as larger quantities of plant material will be more difficult to keep varied and aerated.

Use water and oxygen to keep the decomposition process consistent. Compost piles that get little air create the strongest odors. To keep rotting plant material from building up excessive organic acids, alcohols and esters make sure that the oxygen can move through the pile. To do this, use a pitchfork or specially designed bin that can be turned, to regularly mix the compost. Also, keep the moisture level consistent by watering material that gets too dry, or adding shredded paper, cardboard or sawdust to material that gets too wet.

Use completed mulch or powdered limestone in cases of severe odor problems. If you have tried the above methods and are still experiencing a strong odor from your compost pile, try adding lime or a layer of "finished" mulch to your compost pile. For the mulch, you can use your own garden mulch from last year's compost pile or pre-packaged mulch purchased from a garden supply store. Limestone is a natural odor reducer available from home improvement stores and should be sufficient for even the most stubborn rotten plant odors, whether from composting or just lawn clippings.

Certain chemical odor neutralizers, while available from garden supply stores, should not be used in compost that will be used on food crops; if you are unsure, read the label or contact the manufacturer.