Neglecting one practice may begin the decline of the lawn. The soil should be tested whenever there is any doubt about the general fertility of the soil or health of the lawn. Testing every two or three years is usually sufficient. Fertilizing The average lawn can be kept vigorous and competitive with one to three applications per year of lawn fertilizer at the recommended rate. One pound of actual nitrogen per 1000 square feet is a standard rate for most brands of fertilizers.
Fertilizers vary in the availability of nutrients.
Some of the materials that make up the fertilizer are water soluble readily available. Therefore, they might better be applied at half the suggested rate but more frequently. Organic sources of nutrients take longer to show an effect, but extend their availability over a longer period of time. Synthetic sources of nutrients and water insoluble fertilizers have extended the period of nutrient availability but are usually slower to show results. Most fertilizers contain various mixtures of two or more sources of nutrients.