As a rule, landscapes need an average of an inch of moisture a week, extension agent Rebecca McMahon said. The average is over the course of the year; in winter, you won’t water as much, and in the hot parts of summer you may water more.
The 1-inch rule applies to grass, too, especially fescue.
The 1 inch of water should be applied at one time, as long as the water does not run off. (If it does, stop the water, wait an hour or so, and start watering again, repeating until the inch has been applied and goes into the soil instead of down the street.) This deep, infrequent watering causes roots to reach deep and produces healthier grass that doesn’t need as much water.
Rainfall should be subtracted from the amount of water you put on the landscape.
To save on water, all Wichita lawns can be allowed to go dormant in the summer, at no detriment to their health.
Here’s how much water your grass needs, based on type and weather. Pair the guidelines with getting to know your grass and digging into the soil a couple inches to check the moisture level before watering.
For warm-season grasses Bermuda, zoysia and buffalo:
Spring and fall: These grasses generally don’t have to be watered.
Summer: Apply 1 inch or so a week during the summer to keep them semi-green and out of dormancy. Or skip watering and allow them to go dormant.
Extreme heat: In an extreme summer, such as last year’s, water half an inch every couple of weeks to keep warm-season grass alive even when it is dormant.
Spring and fall: Check the soil for dryness and let the grass tell you when it needs water. When you step on the grass and the blades don’t spring back, or they turn a purplish or gray color, or the blades curl up on the ends like needles, and the top 2 or 3 inches of the soil are dry, give the lawn an inch of water.
When temperatures hit the 90s: Water one inch every three to four days to keep it green. Or, if you let it go dormant:
Normal summer: If you let the grass go dormant, water half an inch every two weeks, at one time, to keep the dormant grass alive.
Extreme summer: In extreme heat – such as last summer’s – water half an inch a week, put on at one time, to keep the dormant grass alive.
Source: Sedgwick County extension agent Rebecca McMahon