Tony Bratsch, Extension Educator, Horticulture at the Effingham Extension Center recently sent this article.

As average temperatures warm, lawns in the area are finally turning green and growing. Though it may seem the ideal time to make the first application of spring fertilizer, it is best to delay until early May, after you have cut the grass a few times.

A delay of spring fertilization is recommended for several reasons. First, it allows grass plants to use nutrient reserves stored through the winter. This is important as it maximizes the effect of fertilizer applied in the Fall. Fertilizer applied in the Fall will easily sustain plants through 4 to 6 weeks of early spring growth.

Also if lawns are fertilized too early, top growth is promoted at the expense of root growth. A delay in fertilizing will cause the turf to root more deeply in the spring, creating a larger and more established root system. This allows better tolerance to the rigors of summer drought, potential grub feeding and diseases.

Another good reason to delay fertilization is to reduce spring foliar diseases. When grass grows too lushly under cool, rainy weather disease occurrence is increased and it weakens the turf.

Lastly, by delaying fertilization until early May, more nutrients are available through the summer months. It is important to use a slow release formulation that will evenly supply nutrients, with less burn potential, as the summer season progresses.

Remember, the standard lawn fertilizer rate is 1 pound of actual nitrogen per 1000 square feet of area. Exceeding this rate will result in excess clippings and increased thatch in the turf. Many fertilizer spreaders have calibration settings for particular formulations or types of fertilizer. These settings are usually noted on the equipment or fertilizer bag. For other spreaders and fertilizer materials, calculations involve knowing your lawn area and the nitrogen concentration of the material used to properly apply the above rate. Nitrogen concentration is the first number on the bag, and is expressed as a percentage. Once the amount needed for your area is calculated, it is best to apply it lightly and overlapped in several directions, until the total amount of material is applied.

On a final note, be sure to keep mower blades sharp, never remove more than a third of top growth at any time, and mow at the right height. The exception to this is the first mowing of the season, in which lawns can be cut shorter to remove debris and "even-up" the appearance. Most tall fescue and bluegrass lawns should be mown at 2.0 to 3.0 inches through the season, and not cut less than 2.0 inches. Zoysia and Bermuda lawns can be maintained at 1.0 to 1.5 inches. A taller turf is a healthier turf, and it will compete better with weeds and root more deeply and effectively. Always avoid "scalping" your lawn.

Fertilization of lawns in the spring is important to ensure good growth and quality appearance through the summer. However it is best to delay this application until the first week or two of May in southern and central Illinois. Additional applications can be made again in early September and a winterizing application in late November for a healthy, beautiful lawn.