The consensus across water-conservation research is remarkably consistent on this point.
The EPA's WaterSense program points out that watering lawns and landscapes during the hottest part of the day wastes a significant share of that water to evaporation before it ever reaches the roots, which is why the agency steers people toward early morning or evening instead.
Iowa State University Extension and Outreach backs this up with a specific window, naming 5 to 9 a.m. as the best time to water a garden, since the foliage dries quickly afterwards and evaporation loss stays low.
Oregon State University Extension Service adds that during the heat of the day, evaporation increases sharply and less water actually makes it down to the root zone, a pattern its horticulturists have observed across multiple regions of the state.
The consensus across water-conservation research is remarkably consistent on this point. The EPA's WaterSense program points out that watering lawns and landscapes during the hottest part of the day wastes a significant share of that water to evaporation before it ever reaches the roots, which is why the agency steers people toward early morning or evening instead. Iowa State University Extension and Outreach backs this up with a specific window, naming 5 to 9 a.m. as the best time to water a garden, since the foliage dries quickly afterwards and evaporation loss stays low. Oregon State University Extension Service adds that during the heat of the day, evaporation increases sharply and less water actually makes it down to the root zone, a pattern its horticulturists have observed across multiple regions of the state.
