What type of lawn owner are you? Do you let Mother Nature take her course, which often cycles between wet and dry, or do you keep your lawn well-watered, comforting yourself about spending a little more on your yard because you never party on the French Riviera?
Watering a lawn might seem uncomplicated, especially with a sprinkler system that’s pre-programmed, but a lawn that’s green and growing can lull us into a false sense that it’s being watered properly. The healthiest method for watering a lawn is often misunderstood.
The concept is simple: Deep watering encourages deep, vigorous roots, while shallow watering causes shallow, weak roots. In practice, though, lawns aren’t always watered this way, which can lead to trouble.
Why is deep watering so important? If my lawn is green and growing, doesn’t that mean I’m watering just fine? Sprinkling lawns frequently and lightly, as many automatic sprinkling systems do, may keep the grass nicely green, but the turf is addicted to its fix of frequent watering. If the watering is stopped for some reason, the lawn can suffer withdrawal, and the shallow turf quickly suffers. A deeply rooted turf has the depth of character to weather adversity and reach deeper into the soil profile to retrieve needed moisture.
Although frequent shallow sprinklings may keep a lawn green, there are other dangers besides shallow roots. An addiction to watering can keep a lawn soft, less tough and more prone to disease. In an interesting quirk of nature, the most pampered lawns are sometimes those that succumb to illness.
Frequent, shallow waterings also don’t give trees located in the lawn the healthy soaking they need. A good term for proper lawn watering is “soak and cycle,” which duplicates Mother Nature’s natural rainfall cycle by soaking the soil and then allowing it to dry slightly. Soaking soil to a depth of 6 to 8 inches encourages grass roots to develop throughout that profile. If our lawn watering only penetrates to a depth of 1 or 2 inches, most of the roots remain shallowly in the thin layer of moist soil.
How much rainwater or sprinkler water does it take to soak to a depth of 6 to 8 inches? The rule of thumb is 1 inch of water per week, in one application, from either rainfall or supplemental sprinkling. On light, sandy soil, this can be divided into two applications.
How do we know how much water we’re applying with each sprinkling? Sprinklers, whether automatic or manual, vary in the amount applied per minute. If we set our sprinklers based on time length alone, we’re unsure how much is applied until we do a simple test.
The best way to tell how much water you’re applying is to set several straight-sided cans, such as tuna or soup cans, on the lawn. Run your sprinkler and monitor how long it takes to collect 1 inch of water in the cans. Then you know how long your sprinklers must run to apply the recommended amount.
Manual sprinklers are fairly straightforward — leave in place for the length of time required. Automatic sprinkler systems usually need the settings adjusted. Some systems might require running two back-to-back start times, after the system has run through all the zones.
Timing of watering is also important. The best time to water is early morning, between 4 and 8 a.m. Watered at that time, grass blades will dry quickly, reducing likelihood of lawn diseases. Watering during evening or night is less desirable as grass blades remain wet longer, increasing chances that disease organisms will thrive.
A note about my gardening columns
I recently was offered, and accepted, the position of horticulturist with North Dakota State University Extension for Cass County. We’re excited to announce my weekly gardening columns, Growing Together and Fielding Questions, will continue with Forum Communications Co. as they have the past six years. Instead of writing as a freelancer, I’ll write as part of my position with Cass County Extension, with the advantage of easy access to the research and resources of NDSU and its specialists. And I can continue doing what I love — writing and talking about gardening. — Don Kinzler.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at firstname.lastname@example.org or call 701-241-5707.