If you have over-applied or spilled fertilizer on your lawn, you must physically remove as much as you can. This can be accomplished by hand or by using a vacuum for small areas. Remember to always follow label safety instructions for handling fertilizers. Once you have collected most of the fertilizer, it will be necessary to water the area heavily for several days. Because fertilizer runoff from lawns can pollute local water systems and streams, caution should be taken to allow water to percolate through the soil before applying more water. Water will help dilute the salts in the fertilizer (which can cause plant injury) and move them out of the root zone.