One of the best things you can do to help keep the Lake Hopatcong environment healthy is avoid using phosphorus on your lawn. Whether you live lakefront or anywhere in the lake’s watershed, choosing phosphorus-free fertilizer means protecting the water from an overdose of nutrients, which can cause a surge in algae and weed growth, choking out oxygen and harming aquatic life. The towns that surround the lake have imposed ordinances that require all fertilizer to contain less than 0.5 percent phosphorus. But choosing phosphorus-free is even better. The best way to determine if a bag of fertilizer is lake friendly is by looking at the three numbers on the front of the bag. The first is nitrogen level, the second is phosphorus, and the third in potassium. So if the middle number is zero, you’re good to go. (Local businesses that sell such fertilizer have “Lake-Friendly Fertilizer” signs.) Dr. Fred Lubnow of Princeton Hydro, which is completing several projects around the lake to help reduce non-point source pollution, suggests local residents have their lawns tested if they’re concerned about not using phosphorus. “Nine times out of ten, if your lawn needs something, it’s lime,” he says. And as long you follow the application standards, lime doesn’t harm the lake environment. There are other tips you can follow to help protect the lake from phosphorus runoff, such as using compost instead of chemically produced fertilizer (that ensures nutrients will slowly release into the soil over time). If you are going to apply chemicals to your lawn, do so when the ground is moist, but not before a rainstorm is expected. And if you live on the lake, be sure to stay several yards away from the shoreline, or any other body of water. So go ahead and make your lawn beautiful—just make sure you’re keeping the lake beautiful, too.