Problems With Crusty Compost

Causes

• Crusty compost can often form in dry areas with little summer rainfall, such as the Western United States, especially between May and October. When compost is too dry, bacteria that begin the composting process by warming up the pile do not have enough moisture to do their job, and materials will not decay.

Water

• The quickest fix for a dry, crusty compost pile is to add water. Avoid adding so much water that the pile becomes soaked and susceptible to other problems. To make sure that water reaches all layers of compost, first place an oscillating sprinkler on top of the pile and water for an hour. Stick your hand into the center of the compost pile and squeeze it. If it is moist enough, a few drops of moisture will come out, and it the pile will be as damp as a wrung out sponge. If the center and lower layers are still dry, turn the pile, water it and repeat the dampness test. Continue turning and watering until the pile is moist enough. Water your pile frequently to prevent it from drying out again, as microorganisms need substantial water to do their job. After watering, cover the pile with a plastic tarp or other plastic cover to keep moisture in.

Nitrogen

• In some cases, a lack of nitrogen-rich materials can cause a compost pile to dry out and become crusty. If your pile contains mostly wood from pruned branches, bark or other brown materials, adding green material like grass clippings or leaves can help the pile to retain moisture. The University of Illinois recommends shredding bulky organic materials and placing them in a 6- to 8-inch layer on the bottom of the pile. This layer can include fine materials, like grass, in smaller, 2- to 3-inch layers. In the second layer, add a 1 to 2 inches of animal manure or a cup of 10-10-10 fertilizer. In the third layer, add 1 to 2 inches of garden soil. Continue to add materials until you have at least a 3- by 3-foot pile.

Location

• A final issue that can cause dry, crusty compost is the location you choose for your pile. Compost piles that are exposed to large amounts of sunlight or high winds will dry out more quickly than those that get less sunlight. Some sunlight is necessary, but choose a spot that gets approximately six hours of sun and is not in an area that is open to high winds.