CORVALLIS, Ore. — If you treat them right, microscopic soil organisms will turn kitchen and garden debris into “black gold.”
“There are more microorganisms in a teaspoon of topsoil than there are people on planet Earth,” said Nick Andrews, organic vegetable Extension specialist and compost expert with the Oregon State University Extension Service. “Compost is similar. It’s teeming with billions of microorganisms for each ounce of compost.”
Those microbes power decomposition — and heat. To kill weed seeds and many pathogens, Andrews said a pile should reach 130–135°F. Turn the pile after its first three to five weeks with a garden fork to add air and break up clumps. If the pile is big enough (about 0.5 to 1 cubic yard) and well built — with a good carbon-to-nitrogen ratio, adequate moisture and porosity — it should heat within a week and stay hot long enough for that first turn.
If your pile won’t heat up
Problem: The volume is too small to sustain microbial activity.
Solution: Aim for 0.5 to 1 cubic yard of fresh material during peak garden season. If you don’t have that volume, “cool-compost” the rest of the year or consider a worm bin.
“Adjust your expectations,” Andrews said. “If the pile isn’t heating, allow it to decompose over a longer period until it looks fully finished — like black gold.”
If it smells like rotten eggs
Problem: Low oxygen and excess moisture. Healthy compost smells earthy, not sulfurous.
Solution: Turn the pile and add dry, bulky materials such as straw, dry leaves or shredded paper. Keep rain out with a tarp or a simple roof. Target about 60%–65% moisture — damp like a wrung-out sponge.
If wildlife finds your pile
Problem: Attractants such as meat, fish, fat, oil, dairy, bread, grains or bones.
Solution: Skip those ingredients if animals are an issue. Manage the pile actively in early decomposition and bury fresh scraps within the pile. Line or wrap the bin with hardware cloth to deter burrowing.
Compostables that are less likely to attract pests include grass clippings, leaves, plant stalks, vines, weeds without seeds, healthy fruit and vegetable scraps, livestock manure and straw. Wood chips, nut shells, twigs, acorns and eggshells are compostable but decompose slowly.
Previously titled Answers to three common compost problems
