Annie Calovich

March 9, 2013

Keep the lawn alive with a minimum of water

As the city of Wichita considers watering restrictions, The Eagle has been asking people about their own water use and how they might conserve water.

As the city of Wichita considers watering restrictions, The Eagle has been asking people about their own water use and how they might conserve water.

One of the responses – “I suppose you could water only every three days or so” – points up the potential confusion that people have about watering.

Watering every three days may sound like it’s conserving compared to someone who waters every day. But watering is not about frequency. It’s about what a plant needs and making sure that the needed water is soaking in, not running off. In our desire to set sprinkling systems so we can forget them, a lot of water is being wasted in Wichita. And in the midst of a drought, we’re running out of it.

With or without watering restrictions, many of us already have spent too much of our budget on water the past two years. So it’s time to learn how we can set out on the right foot this spring, keeping our plants alive with the minimum amount of water.

We’ll start this week with the lawn. Extension agent Rebecca McMahon gives us a plan that takes us from now – with snow-moistened soil – through the summer for whatever type of grass we have. The key will be to get to know our lawn – which is not easy, but is doable – and to keep an eye on it.

The starting point

Recent snows amounted to about 2 inches of rain for our yards, McMahon said.

Whether you did any watering this winter or not, “that’s going to help us out quite a bit as far as getting the soil moist if it wasn’t,” she said.

The first thing to start watching for is the lawn greening up this spring. That will probably be sometime in March for fescue and in April for warm-season grasses Bermuda, zoysia and buffalo.

Pick your tool

“Maybe the best thing every single person, no matter what kind of lawn they have, can do is to get in the habit of checking their soil moisture regularly,” McMahon said. Choose a tool for the purpose, whether it’s a small trowel, a soil probe or a long sturdy screwdriver.

Know your soil

Going into spring now that we’ve had this snowfall that’s acting as a nice soaking rain, we need to step in and water the lawn only when the soil is dry. How to know? Stick that trowel down as far as you can and move it around a bit so that you can pull up a bit of soil, or stick your fingers in to feel for moistness. You should be able to do this without creating a noticeable hole.

“If your top 2 to 3 inches are so dry that you can’t form a ball in the soil, then it may be at the point of watering,” McMahon said.

But you still need to discern more.

“The reality is everyone needs to get to know their own soil,” McMahon said. If you have sandy soil, a screwdriver will go through the soil whether it’s dry or not. If it’s clay soil, even if the soil is moist, you may not be able to get through.

“There are no hard and fast rules,” McMahon said. “You just have to practice and learn what your soil and your grass look like under different conditions, which is difficult.”

So we’re left with rules of thumb, to be amended as needed.

When to water

You’re going to have to cross some hurdles of “if” before you get to the point that you’re going to turn on your own water supply.

And then you’re going to water a particular amount for a particular length of time.

Let’s say you’ve crossed the first “if.” The top 2 to 3 inches of soil are dry.

“The rule of thumb for every spring, especially this spring, is only water your lawn when it’s starting to show signs of water stress,” McMahon said. “That means the blades are starting to curl up almost similar to needles, and maybe they have a purplish or gray color – if you start seeing those signs and the couple top inches of soil are dry, that’s your time to go ahead, especially if there’s no rain forecast ... to water.”

How much to water: Soak and cycle

Watering wisely will mean letting the lawn dry out as much as possible without causing damage. (And lawns will go dormant before they die from dryness. They’re actually pretty tolerant.) The point is to make the roots go deep looking for water, which will make the grass more resilient to the stresses of summer and require less water.

So, put down an inch to an inch and a quarter of water at one time. But the “one time” may require some breaks in the action to allow the water to soak in rather than run off, especially if you have clay soil. Clay does not absorb water as quickly as sandy soil, nor does it dry out as fast. “I think this is another thing that has caused people headaches,” McMahon said.

Clay soil absorbs water at a rate of 0.2 inches per hour. If you round that up to 1/4 inch an hour for ease, that means it would take four hours for an inch to soak in, McMahon said. If your sprinkler is putting down an inch in 30 minutes, much of that is going to evaporate or run off.

“In a lot of situations, people are putting down water too fast, and the soil can’t absorb it. So you end up watering every day because your lawn is not getting enough water,” McMahon said.

The answer? Soak and cycle. Do a test with a tuna can or other straight-sided container to see how much time it takes to put down 1/4 inch of water for your clay soil, for example. Then water only that long, waiting an hour for it to soak in before you turn the water on again. Repeat. It will take four hours.

If you’re watering only one zone or area at a time, you can move from zone to zone in the course of the hour. If you have a newer sprinkler system, you should be able to program it do so, McMahon said.

If you’re using a sprinkler attached to a hose, you may want to keep the sprinkler in one place and water one area a day, moving the sprinkler to water another area the next day, McMahon said. Programmable timers can be set to turn off after a certain amount of time to give you a little more freedom, she said.

In sandy soil, water soaks in at a rate of 2 inches an hour. That means it will take only a half-hour to put on an inch of water. Much easier and quicker for people who live on the west side.

No matter what type of soil you have, however, be sure to keep an eye on what’s going on so that you can intervene when water starts running down the gutter.

If you have a sprinkler system

If you have an in-ground sprinkler system and haven’t had it checked over by a professional recently, do it, McMahon said.

“You can often see problems here and there, but get someone out there who can tell you if the sprinklers are getting good coverage. ... In most irrigation systems, things happen. They get hit by a lawnmower, or grass piles on top, or they get punched down too deep. Getting that checked at least once a year is really important.

“Another step is getting an audit where the company checks to make sure not only are the heads in good working order but are they putting down the same amount of water in each area.” If a system is old or designed in a certain way, one area may not get enough water. In that case, people often overwater the rest of the lawn to make sure that spot is watered adequately.

A system may need to be upgraded for efficiency, and a professional usually is needed to make corrections, McMahon said.

Warm-season grass

Warm-season grasses are pretty drought-tolerant so they get even more “ifs” before watering.

“As we get into April” – when Bermuda or zoysia or buffalo grass starts to turn green – “if it’s just bone dry, give it some water,” McMahon said. “They’re naturally drought-tolerant, so I would err on the side of watering them very little, only if absolutely necessary and the soil being dry and there’s no prospect of rain in sight and the grass showing some stress.

“Most of the warm-season grasses love hot conditions. They still naturally go dormant in the middle of summer. Especially Bermuda; it’s not going to be dead.”

What about fertilizer?

For the purpose of water conservation, there is no reason to fertilize fescue in the spring unless you didn’t fertilize it in the fall. Then you might put half the usual rate of slow-release fertilizer down in May, McMahon said. That would be 1/2 pound of nitrogen per 1,000 square feet. Organic sources are slow-release, including Milorganite, cottonseed meal, alfalfa-based fertilizers and other products derived from plants or animals.

“If you fertilize, you are pushing that grass to grow, and it is going to require more water,” McMahon said.

Crabgrass preventer

If your lawn has gotten thin, weeds will take advantage of the situation and take over the real estate. Crabgrass preventer is probably a good idea to keep at least some weeds out. It usually is applied around April 1, or when redbuds approach but have not entered full bloom. If you apply a short-lasting preventer, you will need to reapply it a couple of months later, no later than June 15. Otherwise you can apply, once, the longer-lasting Dimension or Barricade. Dimension is the best choice if treating a lawn that was planted late last fall. Barricade also has nitrogen in it, so avoid it if you’re wanting to avoid fertilizing.

When to mow

“If the grass is growing, you mow it. If it’s not, you don’t,” McMahon said. As with watering, you don’t want to follow a set schedule; you need to mow when the grass needs it.

“If you’re watering less, your grass is going to grow less.”

This is not the year to scalp the lawn, McMahon said.

Recommended mowing heights for turfgrass are 2 1/2 to 3 1/2 inches for fescue, 1 to 2 inches for Bermuda and zoysia and 2 to 3 inches for buffalo. The mowing height is the height you want the grass to be after you have cut the grass. Follow the rule that you remove no more than a third of the blade at a time when you mow if you’re mulch-mowing; that’s also best for the health of the grass plant and encourages lateral growth for a thicker lawn. As an example, for Bermuda and zoysia, you cut it when it is 3 inches tall and mow it to 2 inches. When it reaches 3 inches again, you repeat.

Err on the taller sides of the recommendations to shade the crowns of the plants, but don’t let the grass get too tall, either, because that brings its own problems.

“If you’re a person that always mows fescue at 2 1/2 inches, 3 inches may be better,” McMahon said.

Going dormant

If you’d like to save the most water possible and let your lawn go dormant this summer, the idea is to gradually taper off any watering to let the grass go dormant. Dormant fescue will still need about half an inch of water every two weeks, enough to keep the crowns hydrated, but not enough to bring the grass out of dormancy. Warm-season grasses pretty much will not need any water in dormancy, unless we have a severe heat wave. Watering warm-season grasses half an inch every two weeks will keep them out of dormancy and moderately green, McMahon said.

Keeping fescue out of dormancy during a hot, dry summer will require a lot of water. If you want to keep fescue from going dormant, you’ll know that it was virtually impossible to keep fescue really green the past two summers, McMahon said. Heat as well as drought worked against it. The grass will lose 1/3 inch of moisture a day in the summer, she said, and would require an inch every three days and more in sandy soil.

No perfection

“These are ideals,” McMahon said. “The closer you can get, the better off you’re going to be. Nothing is going to be perfect, and it’s not going to guarantee your lawn is going to be green all summer if we have another hot dry summer. But it should help.”

Hoping to start over?

People who want to overseed, put down sod or otherwise put in a lawn – even a warm-season one – will need to be able to water enough to get it established this spring.

“There’s a lot of people considering changing over to warm season-grasses, and ... it’s going to require a fair bit of watering to get those grasses established,” McMahon said. “If you’re using sod or sprigs, they’re not available until June. ... Everyone has to make their own decision on whether they think it’s worth it to invest the time and money ... on establishing something new. Whatever it might be.”

Any delay in a decision on watering restrictions “gets hard because there are businesses that make their living planting lawns and sowing grass seed.”

A continued drought will pose a challenge to horticulture businesses, she said. “I would encourage everyone to shop locally, especially if you are buying less due to the drought.”

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