How to calculate how long to irrigate

How to calculate how long to irrigate

You understand the reason for water awareness and conservation. You’re diligently following the Defined Irrigation Schedule adopted in 2013 for the 10 MUDs served by Woodlands Water. You receive the Woodlands Water's weekly irrigation recommendations, and you want to follow those too. (If you don’t receive the weekly email, you can sign up at

But the question remains: how long should I water to put 1” of water on my lawn? How long will it take to put ½ inch? After all, water pressure may vary, different types of sprinkler and rotor heads put out different volumes of water, and other factors may contribute to variations from household to household.

There are some sophisticated logarithms available, but unless you’re an engineer, you might have trouble applying them.

Don’t despair...there is an easy way to find out how much you are watering.

Evenly space six or more straight-sided food containers (tuna cans, cat food cans, even small rain gauges) across a zone.

  1. Run your sprinkler system for 15 minutes.
  2. Measure the water in each can with a ruler.
  3. Add up all the measurements and divide that number by the number of cans. This will give you an average amount of water the system is putting out for 15 minutes.
  4. Multiply the average by 2 (15 minutes X 2 = 30 minutes). Round the final number out to the nearest ½ inch.
  5. This will give you an idea of how much water your sprinkler system is emitting in a half hour.

How to comply with the recommendations and still have a healthy lawn:

  1. If the recommendation is one inch per week, then water one-half inch on each of your Defined Irrigation Days.
  2. If the recommendation is ½ inch, water ¼ inch on each of your DIS days.

If you have a programmable controller, then water each zone twice (cycle and soak method) each prescribed day for the same amount of time as shown in the chart.

Examples of how long to water using a 1" per week recommendation.*

Watering Day 1**

Zone 1Zone 2Zone 3Zone 4Zone 5Total time
4 minutes 4 minutes 4 minutes 4 minutes 4 minutes 20 minutes***
4 minutes 4 minutes 4 minutes 4 minutes 4 minutes 20 minutes

Watering Day 2

Zone 1Zone 2Zone 3Zone 4Zone 5Total time
4 minutes 4 minutes 4 minutes 4 minutes 4 minutes 20 minutes
4 minutes 4 minutes 4 minutes 4 minutes 4 minutes 20 minutes

*This is for illustration purposes only, based on the example in the article. Actual measurements may differ according to your system, water pressure and size of sprinklers or rotors.

**To allow even more water to soak into the ground, water three minutes from each zone, but run each zone four times instead of two.

Rember to use the simple food container method for determining how much water your irrigation system emits.

It’s all about stewardship The drought is over, but water restrictions remain

It’s all about stewardship. The drought is over, but water restrictions remain

Q. Why are we still on water restrictions even though the drought is over?

The Defined Irrigation Schedule, which restricts in–ground irrigation to no more than two days a week, has nothing to do with drought. In fact, it was instituted in 2013, well after the drought was over.

Q. So if it is not about drought, what is it about?

Simply, it’s about being responsible stewards of a vital resource and trying to ensure there is enough water for future generations.

Q. We’ve got plenty of water. The lakes and bayous are full. It’s been raining all the time. Why are the MUDs and Woodlands Water concerned about water conservation?

We currently have approximately 500,000 people in Montgomery County. We have been permitted to pump water from the Jasper and Evangeline aquifers at a rate of about 84,000 acre feet a year. That’s about 30 billion gallons. The combined two aquifers recharge at 64,000 acre feet a year (about 21 billion gallons). That’s a current deficit of about 20,000 acre feet or around 9 billion gallons. And large water volume users in the county (any group using 10 million gallons or more) are under mandate to reduce their usage by 30%. While The Woodlands, the City of Conroe and Oak Ridge North are some of the largest users, there are many more large users within the county.

Q. But aren’t we now taking water from Lake Conroe? Shouldn’t that solve the problem?

Yes. It solves the current problem. But residents still need to look to the future. There are about 500,000 people in the county. By 2035, experts are saying that we will have close to a million here, and that population will continue to grow exponentially after that. Since public water providers are charged by the TCEQ to provide clean drinking water at just and reasonable prices for now and for the future, it’s important to find additional water. Experience from the rest of the country shows that by reducing water consumption by 30%, those billions of gallons can serve future generations. If regions burdened by drought now had the foresight to conserve water decades ago, they may not be having the problems they are having now.

Q. How will restricting lawn irrigation to no more than two days a week help?

Of all the potable water used in The Woodlands (and throughout most of Montgomery County), at least 50% is used to irrigate lawns. In the summer, that can rise to 80% on peak days. Additionally, of all the water used to irrigate lawns, 50% of that is wasted, running off into the street and into storm sewers and ultimately to the Gulf. Lawn irrigation, not toilets or showers, is the largest waster of water by far.

Q. Will this conservation program keep my water rates down?

Water prices will continue to rise across Texas, the nation and the world. We will never again see water prices as low as they are now. And we are still much lower than elsewhere. Cost for the equivalent of 10,000 gallons of water in Britain is about $96. In France, it is $120. Here the cost is approximately half that. Although conservation will help keep water prices from rising as rapidly as they might in other areas, the real value of conservation is to maintain an adequate supply of clean drinking water for our children and future generations.

It’s a jungle down there

It’s a jungle down there

Beneath the cover of your now greening lawn, there exists a teeming jungle of rapacious creatures, eating (usually each other), multiplying and doing all the things that creatures in a jungle do.

Decillions and more single-celled bacteria take in carbon dioxide and convert it to life-giving oxygen to billions of other microscopic organisms. These organisms in turn eat the bacteria. The protozoans, microscopic mites, nematodes and other miniscule creatures are eaten by larger creatures like earthworms and insects. Thousands of miles of symbiotic microscopic fungus, called mycorrhizae, colonize grass roots, providing plants with increased abilities to absorb water and nutrients. In return, the plant provides the fungus with carbohydrates it has formed through photosynthesis.

Your yard is, in fact, a micro-ecosystem, teeming with diverse life. This whole process allows grass roots to grow deeper and stronger, helps turf grasses to fend off diseases like take-all patch, assists in keeping weeds down and pests, like chinch bugs, out. This diversity is what keeps the grass green and lush.

Too much water, fertilizer, herbicides, fungicides and other “cides” adversely affect the life cycles of all these organisms, making turf more susceptible to disease and damage. Too little organic matter can also contribute to short-lived lawns.


According to Texas A&M turf research, grasses like St. Augustine, Zoysia and Bermuda, need no more than an inch of water a week. In fact, one city in north Texas monitored lawns for a year and discovered that the grass there only required a full inch of water for three weeks during the hottest part of the summer. That same city recorded that there was a number of weeks in spring and summer when it rained enough that no irrigation was required.

Rain sensors, connected to irrigation controllers will regulate watering in case it rains. There are even more sophisticated gadgets on the market, which take into account rainfall, evapo-transpiration rates, soil temperature, ambient humidity and temperature. Residents of The Woodlands who live within the area served by Woodlands Water, can get a 50% rebate on the purchase of rain sensors or more sophisticated devices.

Cycle and soak

Different types of soils have different abilities to soak up water. If the soil is hard and compacted (like most of the lawns in The Woodlands), it will not absorb water quickly. Instead of irrigating for 30 minutes per zone, break up the watering time to three 10 minute cycles per zone. That will give water time to penetrate through compacted surfaces.

Organic matter

Perhaps the least understood component of maintaining a good lawn is the part organic matter plays. Organic matter inoculates the soil with beneficial organisms and provides nutrients for organisms already there. It helps increase the water-holding capacity of soil (soil with five percent organic matter can hold up to three quarts of water per cubic foot). It helps to fluff up the soil so air and water can better penetrate it, and so grass roots can grow deeper.

Adding a half-inch of organic matter over the lawn twice a year can produce magical results. Mid-April is one of the optimum times to spread it. There are many residents in The Woodlands who put nothing on their lawns except organic matter twice a year. Their lawns are lush, green and free of disease and weeds.

Are we following the hydro-illogical cycle in The Woodlands?

Are we following the hydro-illogical cycle in The Woodlands?

The hydro-illogical cycle goes like this: “We had a severe drought, but it’s over and we’re getting plenty of rain. Because of that, we don’t have to worry about water conservation anymore.”

The term was coined by Texas State Meteorologist John Nielsen-Gammon, who also asks the question: “Will the recent rains lead to apathy and disregard for the need to prepare for the next drought?”

Drought or no drought, the need to conserve water is a paramount issue, even in our community. Underground aquifers that residents once relied on can no longer sustain our growing population. Surface water supplies, although ample now, are subject to the vicissitudes of the weather.

The largest user of water in The Woodlands is lawn irrigation. Overwatering lawns is also the largest waster of water. Water that runs into the street from irrigation sprinklers is an indication of overwatering. Standing water in the lawn is another. A third indication is the advance of fungal infections – an expensive problem in its own right.

How much water does a lawn need?

During peak summer months (July, August and September), lawns typically need less than an inch of water a week. Based on the water pressure in The Woodlands, that is generally no more than 10 minutes per zone. However, during months when there is sufficient rain, much less, if any, watering is needed. Warm season grasses like St. Augustine, Bermuda and Zoysia are dormant in the winter and need no irrigation during cooler months. In fact, irrigation during these months encourages unwanted insects and fungal diseases.

Defined irrigation schedule

New residents of The Woodlands may not be aware that lawn irrigation from an in-ground sprinkler system is only allowed two days a week. Hand-held hoses, sprinkler hoses, hand watering and drip irrigation watering are not affected by the restriction.

Odd-numbered addresses may irrigate from 8 p.m. Tuesday to 6 a.m. the following morning and from 8 p.m. Fridays to 6 a.m. the following morning.

Even-numbered addresses may irrigate from 8 p.m. Wednesday to 6 a.m. the following morning and from 8 p.m. Saturday to 6 a.m. the following morning. Irrigating newly-sodded lawns or landscape renovation require a variance from the MUD.

There may be surcharges incurred for not following the schedule. Although a warning is given for a first infringement, subsequent infringements may incur surcharges from $50 to $200.

Aerate your lawn to keep it healthy and lush

Aerate your lawn to keep it healthy and lush

Landscapers know that one of the most crucial elements to having a beautiful lawn is healthy soil. Healthy soil is loose and aerated, a place where roots can spread deeply and organisms thrive.

Compacted soil, which lies underneath most lawns in The Woodlands, actually sets off a chain reaction. It encourages puddling. The soil dries out quickly and becomes rock hard. When that happens, air, water and nutrients cannot penetrate the soil. Beneficial organisms that are necessary for healthy soils die and the soil becomes barren. The consequences don’t stop there.

Lifeless soil

Insects, disease and weeds thrive on barren soil. Fungus infections, chinch bugs and other pests attack shallow-rooted grass. Roots struggle to penetrate the compacted soil. They become weak and thin. The beneficial organisms which help process nutrients for the turf and decompose organic material cannot survive in such an environment.

Instead of growing lushly, turf will focus energy on simply surviving. Without moisture, air flow and organisms, it eventually loses the battle. Then the homeowner is forced to resod.


The best practice to combat compacted soil is to aerate followed by a top dressing of organic matter. This allows oxygen, nutrients, micro-organisms and moisture to penetrate into the soil. Aerations involves removing plugs of soil at intervals. Top dressing with organic matter (compost) and water or rake it in. This will help the compost to filter down into the holes.

How to aerate

It’s much better to remove the plugs of soil than to simply spike the soil. Spiking simply compacts the sides of the holes. Aerators come in different configurations. Several are simply hand tools resembling garden forks. However, instead of solid tines, they have small cylinders which remove plugs of soil. Some come with hose attachments. These add water to the hole at the same time they are taking plugs out. There are push aerators, which resemble reel lawnmowers, and larger ones with gasoline engines that power themselves. There are also professional landscaping companies which have large industrial aerators. Some outlets rent aerators.

Organic matter and fertilizer

After aeration, add organic matter. Simply spread ½ inch of compost over the turf and either rake or water it in. A 1,000 square-foot lawn needs about 1.5 cubic yards of compost.

Fertilize lightly. Too much fertilizer, or fertilizer with too much nitrogen, can actually harm turf grass by attracting insects that feed on the grass, or damaging the lawn with high levels of mineral salts It will also cause a high flush of growth that can lead to fungal diseases.

Weed and feed products also stresses turf, especially St. Augustine. These can also damage tree roots. It’s also a waste of money. Herbicides need to be applied in late winter, while fertilizer should be applied in late spring. Using them both at the same time wastes one or the other.

Are Gardeners Happier Than Most? You Betcha!

Are gardeners happier than most? You betcha!

If you’re feeling the winter blahs, here’s a suggestion: instead of reaching for that glass of wine, put on some warm work clothes and work gloves, grab your garden tools and head out to the yard.

Active gardeners say that the simple act of gardening lowers stress levels and lifts spirits. Many gardeners say it’s meditative, a gentle exercise, fun, and allows us to be nurturing and to connect with life on a fundamental level.

Now, there is some scientific evidence to give credibility to their claims.

The soil itself has a natural ingredient that may stimulate serotonin production, which makes people more relaxed and happier. Microbacterium vaccae, a bacteria that lives in the soil, is the origin.

A number of disorders, like obsessive compulsive disorder, bipolar problems, anxiety and depression have been linked to serotonin deficiencies. In recent animal trials using the bacteria, animals showed increased cognitive ability, lower stress, and better concentration than the control group. The results in the animal trials lasted for three weeks after initial exposure.

Scientists are also studying the bacteria in boosting immune systems to treat cancer, Crohn’s disease and rheumatoid arthritis. These recent scientific discoveries give new meaning to “playing in the dirt.”

Here are some gardening activities that anyone can do in February to reduce stress and anxiety and perhaps get a dose of Microbacterium vaccae:

  1. Put organic material around landscape areas and beds. Then add about two inches of mulch above the organic material. Avoid dyed mulch because of possible impurities like arsenic may be present.
  2. Check your irrigation system now to avoid the spring rush. A visit from The WISE Guys is free. Go to to sign up for a WISE Guys visit.
  3. Do not fertilize your lawn yet. Wait until the grass begins to green up.
  4. Fertilize trees, shrubs and vines so the plant roots can absorb nutrients before spring growth.
  5. February is the ideal time to plant roses. Surprise your significant other by planting one or several roses for Valentine’s Day.
  6. Get your soil tested. A soil testing kit is available from Texas A&M Agrilife Extension Service in Conroe or at The Woodlands Water Resources Building, 2455 Lake Robbins Drive. Again, avoid the spring rush.
  7. Do not irrigate your lawn yet. Irrigating now will encourage fungal infections. And remember, your monthly sewer bill is determined by the volume of water used in December, January and February. Using less water during these months lowers your sewer bills for the entire year.
  8. Install a rain sensor, smart irrigation controller, or manual controller.
  9. Harvest the remaining winter vegetables and prepare your vegetable garden for spring planting.
  10. Get your hands dirty and enjoy the benefits of nature.

The Woodlands Water Agency

The Woodlands Water Agency

2455 Lake Robbins Dr
The Woodlands TX 77380
855-H2o-SAVE (855-426-7283)


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For Emergency call
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For Emergency call
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