Organic Gardener's Composting by Steve Solomon

However, lawns given lime or gypsum to supply calcium that is so vital to the healthy growth of clover, and seed meals and/or dressings of finely decomposed compost or manure become naturally healthy. Clippings falling on such a lawn rot rapidly because of the high level of microorganisms in the soil, and disappear in days. Dwarf white clover can produce all the nitrate nitrogen that grasses need to stay green and grow lustily. Once this state of health is developed, broadleaf weeds have a hard time competing with the lusty grass/clover sod and gradually disappear. Fertilizing will rarely be necessary again if little biomass is removed.

Homeowners who demand the spiffy appearance of a raked lawn but still want a healthy lawn have several options. They may compost their grass clippings and then return the compost to the lawn. They may use a side-discharge mower and cut two days in succession. The first cut will leave rows of clippings to dry on the lawn; the second cut will disintegrate those clippings and pretty much make them disappear. Finally, there are "mulching" mowers with blades that chop green grass clippings into tiny pieces and drops them below the mower where they are unnoticeable.

Grass clippings, especially spring grass, are very high in nitrogen, similar to the best horse or cow manure. Anyone who has piled up fresh grass clippings has noticed how rapidly they heat up, how quickly the pile turns into a slimy, airless, foul-smelling anaerobic mess, and how much ammonia may be given off. Green grass should be thoroughly dispersed into a pile, with plenty of dry material. Reserve bags of leaves from the fall or have a bale of straw handy to mix in if needed. Clippings allowed to sun dry for a few days before raking or bagging behave much better in the compost heap.