When should I turn on my sprinklers in Idaho?

Watering your lawn is a fact of life in Idaho. Care should be taken to not start up an automatic sprinkler system too early, as hard freezes can damage the components. Many areas require backflow preventers that are above ground. In the fall these should be drained as part of a winterization to prevent freeze damage. 

In the spring you should wait until temperatures are consistently above 50 degrees before you start your system. You will also want to pay attention to overnight temperature forecasts during the early season. If temperatures are predicted to drop close to or below freezing, you should cover those above-ground components with an old blanket to insulate them and prevent damage. Most years, by May 1st we are past danger for hard freezes, but anything can happen when it comes to the weather in Idaho.

How often should I water my lawn in Idaho?

Lawn Watering and Time of Year/Weather Conditions

During the spring in April to mid May when temperatures are still cool, most cool-season lawns in Idaho will use about one inch of water each week. From about late May to mid August, lawns will use about 2 inches of water per week or slightly more.

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Sprinkler Systems

Whether you are moving hoses and sprinklers or you have an automatic irrigation system, it is important to understand how much water your system is delivering in a given time period. One simple method to determine this is to set out several catch cans or rain gauges over the area to be irrigated. Run the system for 20 minutes, or a known amount of time, and measure the amount collected. Take an average of the can measurements, but also make note of those that are way off the average. This will tell you that you either have a nozzle problem or a rotating head that is stuck, etc. The average measurement can be converted to inches of water per hour and you can use this information to determine how long to run your system on a particular day. As mentioned above, a lawn’s water needs change with the season, so you should change your automatic sprinkler timers to deliver the correct amount of water depending on the time of year. In the spring, for example, you may need to water enough to replace 1 inch of water every 6 days, but in the summer when the grass is using more water, you may need to water every 3-4 days. Adjusting the timer several times during the season will reduce water waste and give the grass exactly what it needs.

While the system is running, it is a good idea to look for problems with sprinkler heads such as clogged nozzles or rotating heads stuck in one position. Clogged nozzles can be cleaned by unscrewing the nozzle or may involve unscrewing a set screw and pulling out the nozzle with needle nose pliers. On some sprinkler heads, the orifice may be replaced. However, if you don’t have a replacement, be careful not to damage the orifice. Sprinkler heads that do not rotate may simply need to be cleaned, but usually need to be replaced as damage to the internal gears could also be a problem. Check your system each spring, taking the time to see each sprinkler operates to its full range since sometimes a head will get stuck at one end of the arc and not the other. Also, be sure the sprinkler heads are in a vertical position so the water is being distributed as designed.

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Water Frequently

Sodded and newly seeded areas should be watered at least 2 or 3 times daily for the first two weeks.

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Watering Device Types

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 Common Irrigation Challenges

Many homeowners have challenges with their irrigation systems. Use the table below to identify more common irrigation issues along with suggested solutions.

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General Tips 

Less is More - More damage is caused to our plants and grass from over-watering than from under-watering. When setting up your schedules be conservative to start and add more time when plants begin to look stressed.

Losing its Spring - Grass signals that it needs water by losing its spring: When you walk across the lawn and see your footprints, your lawn probably needs to be watered. 

Grass Height - Set your mower to one of the highest settings. There are several reasons not to cut your grass too short:

1. Keeping grass longer allows it greater surface area to carry out photosynthesis, which in turn results in healthier plants. In addition, taller grass grows slower than shorter grass. You can use this fact to eliminate up to 20 percent of the mowing you do annually—an average savings of about eight hours a year, not to mention the savings of gasoline and wear on equipment. 

2. By keeping your grass at the upper end of its recommended mowing height, you can prevent most weeds from germinating—and thereby eliminate the need for herbicides.

 

 

 

 

 

 

 

 

 

 

 

 

Water Saving Tips:

Be sure to fix all leaks promptly no matter how small they may seem!!

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When to Water the Lawn

If you find your lawn has taken on a grayish cast or appears to be dull green, it’s telling you that it needs water. You can also check your lawn by walking on it: If your footprints don’t disappear quickly, it’s because the grass blades don’t have the needed moisture to spring back. While it may seem like you can head out to water your lawn anytime during the day, your lawn actually needs more specific care. Watering in the morning (before 10 a.m.) is the best time for your lawn; it’s cooler and winds tend to be calmer so water can soak into the soil and be absorbed by the grass roots before it can evaporate. If you must water in the evening, try between 4 and 6 p.m. which should give the grass blades time to dry before nightfall. The later you water, the greater chance of disease becoming prevalent in your lawn. It’s worth noting, though, that you don’t necessarily have to water your lawn. Lawns are resilient. Established and properly cared-for lawns can survive weeks without water by going dormant (when the lawn turns brown), then recover once the rain returns.

 

How Much Water to Use

When watering an established lawn, it’s typically recommended to water until the top 6 to 8 inches of soil (where most turfgrass roots grow) is wet. Most lawns need 1 to 1.5 inches of water per week—either from rain or watering—to soak the soil that deeply.

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(Sources: © 2002-2022 The Scotts Company LLC | © 2023 University of Idaho | www.Eastidahonews.com | Los Angeles Department of Water & Power)