The grass varieties that are used for lawns, called turf grasses, form a dense, low mat when you mow them regularly. If you properly water, fertilize, and maintain your lawn, you can create a lush outdoor carpet that provides a pleasant area for outdoor activities. Regular water and feeding are required to get these results, though, because traditional turf grass has very shallow roots.
Functions of Fertilizer
Turf grass needs nitrogen and phosphorus to thrive. Without enough nitrogen, lawn grass turns yellow, and grows slowly. It also becomes less dense, and is susceptible to becoming diseased and letting weeds take hole. Phosphorus helps lawn grass develop and maintain healthy roots. Synthetic fertilizers, high in ammonium nitrate and sulfate, are a convenient way to supply these nutrients to your lawn grass. These inorganic, synthetic fertilizers come in granular form for spreading on your lawn, or as a liquid that can be sprayed.
Effects of Fertilizers
Synthetic fertilizers can pollute the water supply if you don't apply and manage them properly. Nitrogen leaches beyond the grass' shallow root zone and into the water drainage system or rivers and creeks. Phosphorus travels into the water supply when phosphorus-enriched soil erodes.
Traditional Fertilizer Application
To ensure that you use synthetic fertilizers safely, follow the directions carefully for the quantity you need for the size of your lawn. Check with your agricultural extension service if you live in an area where the soil is very sandy, or where there is a lot of clay. The amount of fertilizer you can use safely will need to be adjusted. Avoid getting fertilizer on driveways and sidewalks because when the rain comes it will wash quickly into the storm sewers. If you live near a lake or river, don't apply the fertilizer near the shore.
A drought-tolerant grass choice can reduce the effect of fertilizers in the environment. When you water less, there is less runoff and erosion. As a result smaller quantities of nitrogen and phosphorus travel into the water supply. To avoid the need for heavy fertilizing and watering, consider using a grass variety that does well without frequent watering and fertilizing. Zoysiagrass, ryegrass and fescues are drought-tolerant grasses that adapt well as lawn grasses. Consult with your local garden center before you chose a drought-tolerant grass to find a variety that will do well in your climate.
Safe Ways to Feed
If you are interested in providing nutrients to your lawn without the risks of synthetic fertilizers, you have lots of options. Start by leaving the clippings on your lawn when you mow. The clippings are high in nitrogen and will fertilize your lawn as they decompose. Granular or liquid fish fertilizer is another nutrient-rich synthetic fertilizer alternative. You can also spread a thin layer of sewage sludge or peat moss on your lawn each spring to add nutrients.