In maintaining the fertility of our lawns, there is no need for synthetic fertilizers. Synthetic fertilizers supply a lawn with nitrogen, phosphorus, and potassium (“N-P-K”) – the three basic nutrients plants need to survive – which then gives the plant little incentive to grow deep roots, and to produce sugar to exchange with soil microbes for the soil’s own storehouse of nutrients. The result is that chemical fertilizers make your lawn and other plants dependent on them, and dependent on frequent watering because of the resulting shallow, undeveloped root system.