A fertilization program should include timely fertilizer applications in amounts and formulations that meet the requirements of your lawn. Excessive nitrogen applications stimulate production of leaves and stems and increase the mowing requirements. Higher water requirements, increased thatch and increased susceptibility to insects and diseases also results from excessive application of nitrogen. Poor timing of fertilizer applications, such as mid-summer and early fall applications of soluble nitrogen, also increases the likelihood of chinch bug and brownpatch problems in St. Augustine lawns. The amount and formulation of fertilizer to apply depends on soil test results, grass species, environmental conditions and mowing practices.
Soil tests provide information on the availability of major fertilizer nutrients.
Additional applications of these nutrients through fertilization would not improve the quality of the lawn. On the other hand, grass growing on soils deficient in one or more of these nutrients will respond to fertilizers containing these nutrients. Soil tests also suggest the need for lime or other amendments to correct soil acidity, soil salinity or alkali soil conditions. Moderately or heavily shaded areas should not be fertilized as much as areas in full sunlight. Grass growing in shade is more succulent and has a weaker root system than grass growing in full sunlight.