How to Compost Wood Chips

Wood chips can improve the structure of a compost pile and provide bulk matter to fill out small piles. Using wood chips in the right ratio with other materials is critical to keeping a compost pile working efficiently. A pile made using only wood chips may take months or years to fully break down. Turning a compost pile made with wood chips as it decomposes and maintaining the proper level of moisture help speed up the decomposition process.

The ratio of carbon and nitrogen contained in wood chips and other common materials for composting is a major factor determining how quickly they decompose. Green organic materials, like freshly cut grass, tend to have a higher concentration of nitrogen than dry, woody materials like wood chips or sawdust. The best overall ratio of carbon to nitrogen for promoting rapid composting is between 25:1 and 35:1. Wood chips commonly have a carbon to nitrogen ratio of 200:1 or greater. Adding nitrogen-rich materials, like manure, grass clippings or vegetable waste, to a compost pile helps balance out carbon-heavy wood chips.

The microorganisms that break down wood chips into valuable compost need fresh air to break down compost efficiently. Mixing the pile with a pitchfork or shovel ensures all parts of the pile are composted and helps aerate it. Piles that are mainly comprised of wood chips are naturally well aerated because wood chips require turning less frequently than other forms of compost. When the wood chips in the center of the pile have begun to take on a loose, crumbly texture, resembling dirt, it is time to mix the outside of the pile into the center.

Keeping a pile of wood chips moist promotes rapid decomposition. Wood chips can absorb a significant amount of water before they become saturated. The right amount of moisture for composting leaves the pile damp to the touch but not saturated. The wood should look like a wet sponge after it is wrung out. Turning wood chips after they are watered helps keep the pile aerated. Adding too much water impedes composting and may cause the pile to emit foul odors. Covering the pile with a tarp during hot, dry weather helps reduce moisture loss.

The best site for composting wood chips is a slightly raised area where water can drain away from the pile. Wood chips that are overwatered can start to smell rotten and valuable nutrients may leach out of the compost as the water drains. Turning saturated compost and adding more wood chips helps the composting process continue after a pile is overwatered. Composting wood chips are best kept away from structures because the dead wood may attract termites.