Compost Bins

Successful gardens begin with good soil, and for many gardeners that means creating a compost pile where materials decompose and create nutrient rich organic matter to add back into the garden area. Composting is a microbial process that converts plant material, such as grass clippings and leaves, to a more usable organic soil amendment or mulch.

Many gardeners find it’s convenient and economical to compost leaves, grass clippings, and all the leftover plant material from backyard harvests. The composting process is more efficient when pieces are of similar size; for example, use a lawnmower to shred leaves or snip long plant stems in smaller lengths. Other items that compost easily include coffee grounds, peelings and stems from fruits and vegetables, shredded newspaper, sawdust and eggshells. Greasy items, meat products and animal skins are not recommended.

Most urban gardeners choose to contain the compost in a fenced enclosure, a plastic barrel composter, or a three-chambered composting bin. Locate the compost area in a spot that gets partial to full sun, as the materials need to reach internal temps between 130° and 160° Fahrenheit to activate the microbial process. Choose a location that is not windy, as the pile could get too dried out. Additionally, make sure the location is out of the way for backyard activities and shielded from the view of neighboring properties.

The three-chambered bin used at The Fairest Gardens operates as an assembly line, with compost in varying stages of decomposition. The first bin is filled and left to heat up for 3 to 5 weeks. Next, the material is placed into the middle bin for 4 to 7 weeks and a new batch can be started in the first bin. Then the material is placed into the final bin as nearly finished or finished compost material. Turn the piles once or twice a month to help increase decomposition. Water can be added if needed to keep the pile moist, but not soggy.

Most compost piles are ready to use in the garden in 2 to 4 months during the summer; completed compost will be about half its original height. Compost can be sprinkled on top of gardens, or gently raked into garden beds or mixed with potting soil to use in planters. Adding compost to sandy soil will increase its ability to retain water, and adding compost to heavy clay soil will increase its drainage capabilities.

The UMN Extension has more information about creating compost systems and managing soil nutrients.