Fertilizing your lawn can improve its health and beauty, but improper fertilizing practices degrade the health of the soil, the lawn and groundwater resources. It isn't necessary or advisable to overfertilize the lawn to get lush growth. Conscientious and responsible application of fertilizers or using alternative methods for adding nutrients to your lawn can reduce lawn fertilizer pollution.
Most fertilizer recommendations follow a seasonal formula, such as "fertilize twice a year." These kinds of recommendations are misleading because you may not need any fertilizer, or you may need a different kind. First, test your soil. Extension services offer inexpensive soil analysis tests. Garden centers also sell simple soil testing kits. Fertilizing your lawn when it doesn't need it or fertilizing with the wrong balance of nutrients is a waste of time and money and contributes to water pollution.
Lawn fertilizers are usually labeled with a three-number guaranteed analysis. The first number is nitrogen, and the second is phosphorus. Phosphorus found in fertilizers will bind readily to soil and thus will not leach into groundwater supply. The problem occurs when fertilizer lands on sidewalks, driveways or streets. From there, granular fertilizer is blown or carried by water into storm drains, then empties into surface water, such as lakes and ponds, where it causes suffocating algae blooms and encourages water weed populations to explode.
Nitrogen does not bind readily to soil the way phosphorus does. It can leech down through the soil over time if it is not used up by the plants. It seeps into groundwater and aquifers, or runs off into storm drains. When it reaches surface water, nitrogen causes algae blooms that suffocate aquatic life, cause major odor problems and turn water murky. When it enters drinking water supply in the form of nitrate at a rate of ten parts per million, it can cause blue baby syndrome or methemoglobinemia in infants, where the child is no longer able to use oxygen properly.
Although much of fertilizer pollution comes from agricultural runoff, the misuse use of fertilizers on lawns also contributes greatly to the problem. Never fertilize without knowing what your soil needs, and only use the recommended amounts. If granular fertilizer falls on sidewalks or driveways, sweep or blow it back onto the lawn. Avoid fertilizing right before a heavy rain. Water slowly after applying fertilizer to prevent runoff.
It isn't necessary to use high-maintenance turf grasses to have a beautiful yard. Try expanding areas of decorative beds, and plant native or native-adapted plants in them that don't require fertilizers. Try using alternative ground covers, such as ivy, creeping vines and matting perennials, in areas with little foot traffic. Mow turf areas with a mulching lawnmower, and sweep all clippings onto your lawn to give your lawn an extra boost of nutrition. Use a quarter-inch layer of compost over your lawn once a year if additional nutrition is needed.