Q: I’m trying to decide if collecting rainwater would benefit my lawn. How much water would I need to sustain a 4300 sq. ft. lawn?
A: In my view, it isn’t worth collecting water to save a lawn. A lawn needs 1 inch of water per week in hot weather, the equivalent of 600 gallons per 1000 sq. ft. You’d need 2580 gallons per week for your lawn in July. Fescue needs much less water now because the soil is cooler, perhaps 200 gallons per 1000 sq. ft. per week. Whether it’s summer or fall, that’s a lot of water to collect. I’d leave the lawn alone and let nature run its course.