The lure of a green, grassy stretch in your front yard--instead of those bare, patchy areas--can make it tempting to run out, buy the first bag of fertilizer you see and scatter it liberally over your entire yard. While fertilizer can definitely improve grass growth and overall health, it can also cause damage if applied at the wrong time or in the wrong amount. Always follow label instructions carefully in order to get the desired benefit from your fertilizer of choice.
Standard chemical fertilizers have been around for a long time and manufacturers have made big improvements in their composition, but you still need to know what you're getting into. Chemical fertilizers are identified by a series of three numbers, such as 7-3-2. These numbers indicate the percentage of three primary ingredients which are the active component of the fertilizer. The first number represents nitrogen (N), the second number represents phosphorus (P) and the third number represents potassium (K). All three are necessary for healthy grass growth, but not always in the same amount. For example, phosphorus, one of the primary ingredients, is now known to cause problems such as algae when it runs off into waterways, so look for a fertilizer with a lower amount of phosphorus. There are many organic varieties of chemical fertilizer available, as well. Be sure the chemical fertilizer you purchase is labeled for home or residential use.
Nitrogen is essential for healthy plant growth, so it has always been an active component in lawn fertilizer. However, too much nitrogen too fast can cause an excessive growth spurt, which ends up actually weakening the grass. Look for an organic fertilizer with a slow-release nitrogen; this type of treatment provides nutrients to the soil at a rate the grass can handle, promoting healthy growth and a stronger root system. Follow the label instructions carefully to avoid overfeeding.
Barbara Damrosch, author of "The Garden Primer," advises great care in using chemical fertilizers. Lawns treated too often with chemical fertilizers, Damrosch says, can actually become chemically dependent. The quick burst of food, especially if applied too often or at too great a rate, can cause them to depend on this food source rather than developing deep roots. Damrosch advises using a gentle approach to lawn feeding; she recommends either compost or dehydrated cow manure, which can be sprinkled over the lawn evenly throughout the grass, with a slightly thicker layer over bare spots to encourage additional growth.