Most grasses, like all living things, do best when their nutritional requirements are met "completely." This has given rise to the formulation of so-called "complete" fertilizers. Such products will contain four times as much Nitrogen as Phosphorous and twice as much Nitrogen as Potassium. This 4-1-2 formulation is often sold in a 16-4-8 analysis, and includes trace minerals and nutrients, such as Iron and Zinc. Avoid the heavy, repeated use of high Nitrogen fertilizers, which contain 5, 6, even 7 times as much Nitrogen as anything else in the bag. Applying these will get the desired short term results--the grass will develop a lush green canopy. But overdoing it will have predictable long term results. The grass will not be able to develop the root system it needs to support that canopy, so the grass will be more susceptible to drought. The grass will also not be able to develop a capable immune system, so the lawn will be more susceptible to disease. Diseased, drought stressed turf is then a favored target of insect pests. Two applications of 16-4-8 per year--once in spring, once in early fall--will provide very good color and growth for your St. Augustine, Bermuda or Zoysia lawn (Centipede needs a special fertilizer). If additional color and growth is desired, light applications of high Nitrogen fertilizers can be made through the growing season.
