Organic lawn care nourishes the soil; the synthetic approach feeds the plants. Grass thrives in soil full of beneficial bacteria, earthworms, and other organisms fed by organic sources of nitrogen. "Studies have shown that root mass increases as more organic matter is available," says Paul Tukey, founder of the SafeLawns Foundation (safelawns.org
). Increasing organic matter in the soil also helps it to hold water, which encourages deep roots in all but heavy clay soil. The deeper root zone of organically treated lawns makes them better able to weather drought, pests, and diseases than shallower-rooted, synthetically treated lawns.