Long Islanders love their lawns, and work hard to keep them green and free of weeds. More than 200,000 acres of Long Island are lawns. These lawns are as green as they are because they are fertilized every year. Some of the fertilizer is used by the grass roots, but quite a bit of it leaches into the soil and goes down into our aquifer system – our drinking water.
One of the compounds in fertilizers is nitrogen. Whatever nitrogen passes through the soil ends up ultimately in our water supply as nitrates. Some wells have had to be closed because the levels of nitrates reached unsafe levels.
What can you do to help protect our water supply?
One thing that would help is to have smaller lawns. You can plant other types of plants that require less water and can make your land even more attractive. If you do this, choose plants that are more drought resistant. There are many kinds of ground covers that require no fertilizer and very little water. In areas that are not used much, you can plant ivy, pachysandra or myrtle to reduce your lawn area.
For the part that remains a lawn, you can test for acidity of the soil and add lime to bring it to a pH level of 6.5. Lawns grow best and fertilizer is most efficient at this level. 50 pounds per 1,000 square feet every 2-3 years (25 pounds in the fall and 25 pounds in the spring). Also, use as little fertilizer as possible. A slow-release fertilizer is best because it provides a constant supply of nitrogen and does not leach down as quickly, allowing it to be available to the roots for a longer time period. It is more expensive, but can be used less often.
You should also not cut the grass too short. By allowing the grass to grow 2” high, the roots will be healthier. Only the top 1/3 of the blades should be cut off, and if cuttings are left in place, they quickly decompose and provide food for the roots, reducing the need for fertilizer even further. (Do not leave too much of the cuttings!) If you water less frequently, but for longer periods of time, deep roots will develop. Also, remember that some types of grass are hardier than others. Do your research, find the best type of grass for your property.