FYN Principle #3 - Fertilize Appropriately
If compost is not available or if you need to fertilize, a basic fertilizer that contains slow-release nitrogen and other essential nutrients is the most environmentally-safe and cost effective alternative. At least 30 percent of the nitrogen in the fertilizer should be listed as slow release. Slow-release nitrogen fertilizers usually cost more, but fewer applications will be required. Besides, a few dollars can make a big difference in protecting streams and bays.
Avoid using fertilizers that contain weed killer or insecticide. Such chemicals should be used only as a last resort when environmentally friendly pest control options fail, and they should be used only on affected areas.
Turf areas tend to have higher nutritional needs. If the lawn just won't green up, even after a good rain, first try applying chelated iron or iron sulphate instead of a complete fertilizer. An iron deficiency may be causing a less robust color.
When applying fertilizer, use a maximum of one pound of nitrogen per 1,000 square feet no more than twice per year (March and October). However, you may be able to use half the amount and achieve excellent results. You can also reduce the risk of nitrate leaching into ground or surface waters by applying one half pound of nitrogen per 1,000 square feet four times per year (March, May, September and early November).