Author: Dianne DeLongchamps
- How often should I water my lawn in Colorado summer heat?
- Why does deep, infrequent watering beat watering every day?
- How much water does a Colorado lawn need per week?
- How deep does an inch of water actually get?
- What's the best time of day to water a lawn?
- How do I find out how much water my sprinklers put down?
- How do I know when to water again?
- Am I overwatering my lawn?
- FAQ
How often should I water my lawn in Colorado summer heat?
Water established Colorado lawns two to three times a week in summer, deeply, rather than a little every day. We aim for 1 to 2 inches of water per week, closer to 2 inches in the real heat from roughly mid-July to mid-August. Overnight and early morning are the efficient hours. CSU Extension points to the window between 10 p.m. and 6 a.m.
That’s the standard on every lawn Clean Air Lawn Care treats in Fort Collins, Windsor, and Timnath: 1 to 2 inches a week across two to three deep waterings, 2 inches from mid-July to mid-August. Luke pairs it with mowing at 3 inches minimum and 3.5 in July and August. Most of the grass we treat is Kentucky bluegrass and turf-type tall fescue. CSU calls Kentucky bluegrass “the most widely used lawn grass in Colorado,” and we see it everywhere.
Standing at the hose bib in August, you may wonder whether to just water every day. A lot of watering advice online was written for humid climates.
Why does deep, infrequent watering beat watering every day?
Water a little every day and you only wet the top inch or two. Roots follow the water, so they stay shallow. The first hot, windy week you’re away, that lawn is in trouble.
CSU on frequency: “For most Colorado soils, irrigating once per week works in the spring and fall, and twice a week works in the summer.” That’s your starting point, not your ceiling, we run two to three.
CSU is equally clear about the gap between waterings: “Do not irrigate again until you see signs of wilt. It’s important that the soil profile dries somewhat between irrigation applications.” The drying-out period isn’t neglect, it’s part of the program.
How much water does a Colorado lawn need per week?
Our forecast of 1 to 2 inches (with 2 inches expected in the most intense areas) aligns perfectly with the data that Colorado State University put out.
CMG GardenNotes #265 includes a seasonal table that puts July and August at about 1.5 inches per week. CSU fact sheet 7.202 says a high-quality bluegrass lawn “may need up to 2.25 inches of water per week under hot, dry, windy summer conditions.”
How deep does an inch of water actually get?
On clay soil, it takes “1 to 1 1/2 inches of water to moisten the root zone to a 6-inch depth.” On sandy soil, that same root zone “can be moistened to 6 inches by as little as 1/2 inch of water.”
Much of the Front Range is clay. On typical Fort Collins or Windsor ground, half an inch a week isn’t reaching the roots, you’re wetting the surface and evaporating most of it.
What’s the best time of day to water a lawn?
CSU 7.199 is direct: “The best time to irrigate your lawn is between 10 p.m. and 6 a.m.”
CSU 7.202 phrases it differently: “The most efficient time of day to water is late evening and early morning (between 10 p.m. and midnight or 8 and 9 a.m.).”
CMG GardenNotes #265 adds the reason: “Many water providers encourage homeowners to water their yards between 9 p.m. and 9 a.m. Winds are typically less at night, and evaporation loss will be lower.” Our local water district currently recommends a 6 p.m. to 10 a.m. window.
You may have heard that evening watering causes fungal disease. CSU answers that in 7.202: “watering at night does not encourage disease development.” That research is about how long leaf blades stay wet. It comes out of NC State and applies to humid climates, not a dry night in Northern Colorado.
How do I find out how much water my sprinklers put down?
All of it is useless until you know your system’s output. The catch-can test takes twenty minutes.
Set out 5 to 10 identical containers across a zone. Run it 15 to 20 minutes. Measure the depth in each one, “to 1/10″ if possible,” and average them.
On containers, GardenNotes #265 warns, “Do not use short cans like tuna cans as they are too shallow, and water may splash out.” Use straight-sided containers a few inches tall.
Take your average to CMG GardenNotes #266, “Converting Inches to Minutes,” for real run times.
How do I know when to water again?
Two signals, both verified by CSU: wilt, and footprints. If footprints stay pressed in instead of springing back, it’s time. A well-watered lawn in late-summer heat looks duller green than in May. That’s normal.
Am I overwatering my lawn?
From CMG #265: “In unusually hot weather, if dry spots do not pop up, the lawn is over-watered.”
And from CSU 2.900, on necrotic ring spot, which CSU calls the most common lawn problem in Colorado: “Do not overwater. This is perhaps the most important prevention practice for NRS.”
Luke is out on lawns across Fort Collins, Windsor, and Timnath most days of the week, and the thing he notices most is how differently two lawns on the same street respond to the same schedule; soil, slope, and sun exposure change everything. The deep-and-infrequent principle holds up nearly everywhere we go, but the run times never do. If your lawn isn’t bouncing back the way you’d expect, we’re always glad to take a look.
Clean Air Lawn Care Northern Colorado is owned by Dianne, Paul, and Luke DeLongchamps — a family business serving Fort Collins, Windsor, and Timnath with organic lawn treatments and solar-powered electric equipment.
