Covered and Aerated Compost Systems

Covering compost piles with breathable fabrics can help reduce water needs during hot, dry weather, and may help avoid soggy, anaerobic piles during periods of heavy rain. Many, but not all, cover systems include some form of forced aeration, using pumps to push or pull air through the pile core.

Forced aeration helps avoid anaerobic conditions within covered or static piles, since normal convective air flow may be restricted by either the cover itself or the size of the pile.

Covered or aerated compost systems may help composters reduce odors as well as regulated air emissions. However, not all manufacturers have sufficient research data to prove that their systems will meet the emissions reductions mandates of local air quality districts such as the South Coast Air Quality Management District.

Systems may use positive or negative aeration. Positive aeration uses pumps to force air into the pile. Negative aeration uses pumps to suck air through the pile. Positive aeration systems may rely on beneficial microbes living just under the cover to destroy pollutants, such as volatile organic compounds (VOC). Negatively aerated systems typically route the pulled air through a device such as a biofilter or a furnace, which will destroy VOCs and other emissions.

The Department of Resources Recycling and Recovery (CalRecycle) does not endorse specific technologies. New listings are encouraged and published upon CalRecycle approval and permission from manufacturer. The following compost system vendor and designer/builder descriptions are based on information provided by the manufacturer. CalRecycle has not verified any of the claims in these descriptions. Please contact each vendor directly for pricing information.

Covered System Vendors

Other Resources

To learn more about other types of compost system providers, to find producers of compost and mulch, or to learn more about composting air emissions, please use the links below.

For more information contact: Organic Materials,