Nothing says suburban success like a lush, emerald green lawn. In the quest for that jewel of the neighborhood, homeowners may be tempted to apply one last dose of fertilizer this week. If this is you, step away from the spreader.

One nutrient found in all fertilizers is nitrogen. Essential for plant growth, it can also cause health problems when in excess of 10 parts per million (or 10 milligrams per liter), the highest level of nitrate allowed in drinking water as per the Environmental Protection Agency. It has forced the closing or decontamination of wells in Centereach and Northport, according to the 2010 water quality report by the Suffolk County Water Authority. When it does reach groundwater, nitrogen can cause Methemoglobinemia, also known as blue baby syndrome, a reduction in the blood’s ability to carry oxygen that can result in digestive or breathing problems and sometimes death in infants.

Andrew Manitt is research director for The Neighborhood Network, an environmental organization that promotes using slow-release organic fertilizer. He suggests going organic because “it mimics what happens in nature and it is not water soluble, so it’s less likely to leach into groundwater.”