of large enough quantities of organic material in the soil. This
organic matter holds a massive reserve of nutrition built up over
the years by the growing plants themselves. When, for reasons of
momentary aesthetics, we bag up and remove clippings from our lawn,
we prevent the grass from recycling its own fertility.

It was once mistakenly believed that unraked lawn clippings built up
on the ground as unrotted thatch, promoting harmful insects and
diseases. This is a half-truth. Lawns repeatedly fertilized with
sulfur-based chemical fertilizers, especially ammonium sulfate and
superphosphate, become so acid and thus so hostile to bacterial
decomposition and soil animals that a thatch of unrotted clippings
and dead sod can build up and thus promote disease and insect
problems.

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