To the Editor:

The article about toxic algae blooms closing Rosedale Lake to swimming and boating [pg. one, July 17] should be a wakeup call. While the experts quoted correctly identify storm water runoff and overdevelopment as causes, only an oblique mention of “lawn and garden fertilizer” pointed to a major source of the problem: us. By that I mean we homeowners with large areas of lawn: lawn is the largest “crop” in America by acreage. Homeowners and the lawn maintenance companies we hire apply ten times as much pesticide/herbicide per acre as farmers, and are constantly applying fertilizer to achieve that perfect green look. And unlike commercial sources, the tainted discharges (via storm water) from individual homeowners’ lawns are unregulated. In my household, I’ve declared the backyard fertilizer and herbicide-free, but am still working to get the same regime in the front.

We can all do more. At a recent conference sponsored by the Scott Arboretum of Swarthmore College, the Pennsylvania Horticulture Society, Morris Arboretum, and other prominent institutions, the director of the South Carolina Botanical Garden spoke proudly of reducing 65 acres of lawn when he took over to the current nine, with an eventual target of three. The huge lawn was fertilized three times a year, with pre-emergent herbicide applied every spring. Since the area of lawn was greatly reduced in favor of trees, shrubs, and herbaceous plants, the result has been an explosion of the numbers of bird species (122 to 209), small mammals (from rare to abundant), frogs, and toads.  We can emulate this by gradually expanding the boundaries of areas that have trees and shrubs, with a corresponding decrease in grass.

By planting more trees and shrubs, especially natives, and reducing lawn that generates harmful runoff, we can enjoy the benefit of increased numbers of birds, butterflies, and other animals in our own backyards. Trees, of course, reduce runoff by absorbing storm water with their roots and by breaking the fall of rain with their leaves. And as is well known, trees absorb the harmful carbon dioxide that is causing climate change. That is why a central recommendation of Princeton’s proposed Climate Action Plan is to plant more trees. I hope all Princeton residents will consider incrementally reducing their lawn, and certainly their use of fertilizers and herbicides, as we see the unacceptable consequences for our water quality — both the water we swim and boat in, and the water we drink.

Wendy Mager
Cherry Hill Road