Fall Composting Tips to Turn Leaves into Garden Gold

By Andi Anderson

As fall leaves begin to pile up, Iowa State University Extension and Outreach horticulture experts encourage gardeners to turn that seasonal debris into valuable compost. By recycling organic materials like leaves, grass clippings, and garden waste, gardeners can improve soil health while reducing yard waste headed to landfills.

“Composting is a natural process that turns organic material into a dark, crumbly, earthy-smelling material called humus,” said Aaron Steil, consumer horticulture specialist with ISU Extension and Outreach. “It is an excellent soil amendment that improves soil structure, increases water-holding capacity, and provides nutrients.”

To create effective compost, a proper balance between carbon-rich “browns” (dried leaves, straw) and nitrogen-rich “greens” (fresh grass clippings, vegetable scraps) is essential.

The ideal carbon-to-nitrogen ratio is about 30:1. Steil recommends building piles at least three feet tall and wide to retain heat, turning them regularly for airflow, and keeping moisture levels similar to a “wrung-out sponge.”

A three-bin compost system works best — one bin for collecting materials, one for active composting, and one for finished compost ready for garden use. Although decomposition continues even if the carbon-to-nitrogen ratio isn’t perfect, adding nitrogen-rich fertilizer or shredding materials can speed up the process.

Steil cautions against composting meat, dairy products, pet waste, weed seeds, or diseased plants, as home compost piles rarely reach the 150–170°F required to kill pathogens. “Even with ideal conditions, the pile may not be hot enough for long enough,” he noted.

Finished compost, often called “black gold,” resembles dark, rich soil and has an earthy aroma. It can be used to top-dress lawns, mulch trees, or enrich garden beds. Beyond its fertility benefits, compost enhances soil aeration, boosts beneficial microbes, and improves moisture retention — setting the stage for a thriving spring garden.

Photo Credit: iowa-state-university