The main objectives of turning are to shift materials from the outer parts of the pile closer to the center for better decomposition, and to incorporate oxygen. During warm weather, turn the pile once a month. In cool weather frequent turning is not recommended because it allows too much heat to escape. Piles should be turned immediately if ammonia or other offensive odors are detected. Within a few weeks after starting, the pile should be hot in the center.
Heating generally indicates that the pile is decomposing properly.
Failure to heat may be caused by too little or too much water, improper aeration, packing too tightly, or a pile that is too small. During dry weather it may be necessary to add more water. The moisture content of the interior of the pile should be observed while turning. The major horticultural use for leaf compost is to improve the organic content of soil. Leaf compost is not normally a fertilizer, because it is too low in nutrients.