Top 5 Composting Mistakes

Most of us are aware of the importance of “garden gold” for improving Nevada’s soils. But, how successful have you been in making your own? Not very? Here are some mistakes gardeners make when composting. Correcting them may help you find a gardening “pot-of-gold” at the end of the rainbow.

Composting is controlled decomposition of organic matter. Organic matter decomposes on its own over time – a long time. Your role is to speed that process along. Gathering waste from your landscape and kitchen into a pile is only the beginning.

Mistake No. 1: Packing the organic materials in your pile too tightly. That forces out air and slows down the decomposition process. Turn your rotating bin once a week, or find a bin with open slats on the side. This allows oxygen in so the decomposer microbes can do their job. Piles larger than 5 feet by 5 feet will need occasional turning. Or, you can place an aerator chimney in the center – a PVC tube with air holes drilled in the sides will work.

Mistake No. 2: Not mixing green and brown materials. You need about two parts browns to one part greens. Brown materials contribute carbon and include dry crunchy things like fallen dry leaves, dried pesticide-free grass clippings, hedge clippings and other pruned plant parts. Green materials provide nitrogen and include kitchen waste (no oils or animal products), fresh green plant waste, and manure from non-meat-eating animals. You need a good balance of greens and browns to give microbes the diet they need to be active.

Adding large bulky materials to your compost bin slows down the composting process. Chip, shred or blend materials before adding them for best results. Photo by Ashley Andrews.

Mistake No. 3: Adding large bulky materials to your pile. Leaves, wood chips, newspapers or cardboard are great additions, but they must be chipped or shredded into half-inch diameter pieces to increase the surface area for microbes to feed. Put kitchen waste through a food processor or blender to break them down. Large materials mat over time, interfering with moisture absorption and keeping out oxygen.

Mistake No. 4: Not providing a source of microbes. We have plenty of decomposer microbes and insects in our soil, but sometimes it’s not enough. Layer in compost from a previous batch, soil from your garden or manure from vegetarian animals. This will provide a more consistent source of inoculant that will jump-start the process and move it along quicker.

Mistake No. 5: Not monitoring your pile. Get a good, long-stemmed compost thermometer, and record the temperatures in the center of the pile regularly. Active composting temperatures range from 90 to 140 degrees F. While you’re there, stick your fingers in the pile to check for moisture. An active compost pile should be moist like a wrung sponge, not dripping wet.

Let your compost rest for a few weeks after all materials have broken down and are unrecognizable. This cures the pile and allows temperatures to come back down to plant-friendly levels.

To learn more, attend the free Gardening in Nevada talk “Composting – Some Like It Hot,” 6-8 p.m., March 14 at Bartley Ranch Regional Park in Reno.

Heidi Kratsch is the northern area horticulture specialist with University of Nevada Cooperative Extension. Horticulture questions? Contact 775-336-0265 or, or visit