A shredder can be used before putting material in the pile, and is essential if brush or sticks are to be composted. A low cost method of reducing the size of fallen tree leaves is to mow the lawn before raking or run the lawn mower over leaf piles after raking. Raked piles should be checked to insure that they do not contain sticks or rocks which could cause injury during operation of the mower. If the mower has an appropriate bag attachment, the shredded leaves can be collected directly. In addition to speeding up the composting process, shredding will initially reduce the volume of the compost pile.
Microbial activity is affected by the carbon to nitrogen ratio of the organic waste.
Because microbes require a certain amount of nitrogen for their own metabolism and growth, a shortage of nitrogen will slow down the composting process considerably. Materials high in carbon relative to nitrogen such as straw or sawdust will decompose very slowly unless nitrogen fertilizer is added. Tree leaves are higher in nitrogen than straw or sawdust but decomposition of leaves would still benefit from an addition of nitrogen fertilizer or components high in nitrogen. Grass clippings are generally high in nitrogen and when mixed properly with leaves will enhance decomposition. Poultry litter, manure or blood meal can be used as organic sources of nitrogen.