Lawn fertilizer, especially when applied incorrectly, fertilizes a lot more than just your lawn. Excess nutrients are carried by runoff into ponds and lakes. The same nutrients that help grass grow also help algae and pond weeds grow, leading to algal blooms and excessive aquatic plants that are not only unpleasant to look at and to swim in, but also affect food quality and habitat for fish and other organisms.

Does this mean environmentally aware citizens are doomed to have unattractive lawns? No. By following a few simple recommendations, you can make sure that you're not contributing excess nutrients to your streams and lakes.

Responsible Fertilizing Practices

1. Start with a soil test.
Make sure your lawn needs fertilizer, and find out how much you should be applying. Your test results will include recommendations on what nutrients you should add to your lawn.

2. Choose the correct product.
If you had a soil test, be careful to read the labels and buy the correct fertilizer. If not, consider using phosphate-free fertilizer (and therefore phosphorus-free).
Why? Lakes and streams may be phosphorus limited. When excess phosphorus from lawn fertilizer and other sources enters streams and lakes, algae and other plants have all they need.

3. Apply the product correctly
Fill granular fertilizer spreaders on a hard surface where any spills can be easily cleaned up. never wash off fertilizer spills into the street or other hard-surface areas where they can easily enter storm sewers and ultimately surface water areas. Wash off granular fertilizer spreaders over turfed areas to prevent runoff of fertilizer from hard surfaces. Fill and clean liquid fertilizer applicators over turfed areas for similar reasons. Close the gate on the fertilizer spreader when crossing hard-surface areas or go back and sweep up the material. Reuse it another time or put it back into the spreader. Try to use a drop spreader, which is more precise but slower than a rotary type spreader near surface water. Next to shoreline areas, apply fertilizer around the perimeter of the property with a drop spreader to create a safety zone. Avoid getting fertilizer into natural drainage areas or pathways on a property. These areas may not necessarily be hard-surface areas, but they can carry fertilizer directly into the surface water before having the chance to infiltrate into the surrounding turf/soil area. Leave grass clippings on the lawn area to decompose and recycle nutrients back to the turf area. They should not be blown or raked into street gutters or onto sidewalks and driveways where they may be carried with runoff water to surface water. Nutrients released in water through decomposition may cause undesirable algae and vegetative growth.