I was as surprised as anybody when I started doing research on this topic. I mean, one would think that it’s a waste of water. It maybe isn’t.
What started my search into this topic were my neighbors, especially across the street, who have one of those sprinklers that snake along the hose. They always have the sprinkler shooting water out 10 feet off the lawn, on to the driveway or street. I assume they figure that this means they’re guaranteed good coverage on their lawn.
But according to experts at the University of Chicago extension, in a joint study with hydrologists in Arizona (where water is a precious commodity indeed), by watering at least 4 feet beyond the lawn on to impermeable services you help cool down the area around the lawn, thus increasing root growth and less grass burn. In fact, that water hitting hot asphalt vaporizes, becomes a quasi steam, and penetrates the grass through the blades, too. Here are the numbers:
-- 1,000 square foot sample lawn watered for 30 minutes produces ¼” of rain.
-- Burned grass watered just on the lawn took 2 days longer to green up, compared to the same size lawn watered 4 feet beyond the edges on to impermeable surfaces.
-- Soil temp beneath the grass before watering was 84 degrees 4 inches deep, soil temp after was 78. When you water beyond the grass soil temps stay cooler longer, too.
So, water the street! In fact, instead of sweeping your driveway of lawn clippings, hose them off! Water can do anything muscle power or prairie winds could do, but with more bling. Wasting water is fantastically good for the environment!