PB1038 Fertilization & Management

Fertilization and liming practices based upon a soil test help ensure the most cost efficient and environmentally sound development and maintenance of lawns. A soil test is especially critical when soils test low in pH, phosphorus or potassium. A properly fertilized and limed lawn is usually greener, more vigorous, less weedy and more attractive than a poorly fertilized lawn or one suffering from the effects of low soil pH (soil pH is a measure of the soil’s acid content).

The primary nutrients (nitrogen, phosphorus and potassium) must be added to most lawns, since soils in Tennessee seldom furnish adequate supplies. The secondary and micronutrients essential for lawngrasses generally occur in sufficient amounts in Tennessee soils and do not usually need to be applied.

Amounts of phosphorus and potassium to use when establishing and maintaining lawns are best determined by soil testing. Plant-available nitrogen usually does not remain in the soil for an extended time and must be applied more frequently than phosphorus or potassium. Therefore, the amount of nitrogen to use for healthy lawns is usually based upon measurement and/or visual observation of lawn quality at various rates of applied nitrogen. Environmental impact and water quality are increasingly important considerations when making appropriate fertilizer recommendations.

Limestone is recommended when establishing a lawn on soil having a pH less than 6.1. Limestone is also required for maintaining healthy lawns. Normal weathering of soils and fertilization lower soil pH over time.The amount of limestone to use should be determined by a soil test.