UNMC LiveGreen: Composting your kitchen scraps, part two

This is the second in a two-part series on composting.

This spring, we built an outdoor compost bin from four scavenged shipping pallets. The site we chose is near the back of our yard, with good drainage so the pile won’t be sitting in water.

We set the pallets on end and leveled the ground where necessary to make a sturdy bin with 90-degree angles. We fastened the pallets together at the corners with 36-inch plastic zip ties.

An outdoor compost pile should be a minimum of three feet deep by three feet wide by three feet tall. Essential ingredients are brown material (leaves, shredded paper, twigs), green material (grass clippings, vegetable scraps from the kitchen) and an activator (dirt, compost, or manure from horses, cows, guinea pigs, rabbits or chickens). Cat and dog feces may contain parasites that can be transmitted to humans and should not be included in a compost pile.

To build the pile, we started with a four-inch layer of sticks and twigs to allow air to circulate up from underneath. Next, we added a four-inch brown layer using leaves that had protected the garden over the winter and dry prairie grass trimmings. We topped that with a shallow layer of garden soil to get the pile going and added fresh grass clippings and coffee grounds for the green layer. We continue to alternate the brown and green layers, using dead leaves, dried prairie grass and fresh grass clippings, and burying vegetable scraps from the kitchen about 10 inches deep (no meat, oil, or bones as they become rancid and attract pests). The pile should be moist but not wet.

The internal temperature of a good compost pile should be between 120 and 150 degrees to kill any weed seeds (which is particularly important if manure is used). When the interior temperature drops, it’s time to mix the pile using a shovel, garden fork or aerator. Mixing the pile speeds up the process. The pile will get smaller as its ingredients break down and become rich soil.

What do we do with the finished compost? Mix with potting soil for house plants, top-dress the garden and spread it a quarter-inch deep on the lawn. It rebuilds the soil and makes our plants healthier, more vigorous, and more disease-resistant.