Smart Lawn Irrigation

Summertime lawn watering uses almost 50% more water than indoor winter usage, and depletes the groundwater that sustains local streams and ecosystems.

Often, this water is wasted due to a general misunderstanding about lawn care. In fact, some experts estimate that more than half of the water used for irrigation is wasted due to evaporation, runoff, or over-watering.

While we would prefer that folks don’t water their lawn, we hope that those that who choose to irrigate will be as efficient as possible. A beautiful lawn does not require a lot of water.

How much water do I really need?

One inch of water per week from rain and/or irrigation is enough to keep a lawn green.  Our area receives on average, ¾” of rain per week during the summer.

  • Test your lawn by stepping on a patch of grass; if it springs back, it doesn’t need water.
  • Plan to water early in the morning or during the late afternoon, to avoid excess water evaporation. And, avoid watering on windy days. Water evaporates more quickly when it’s windy!
  • Follow weather reports, or set up a simple rain gauge to determine how much rain has fallen.
  • Don’t overwater, as it can cause harmful fungus outbreaks.
  • Avoid watering when it’s windy, to limit evaporation.
  • Make sure that your sprinkler is watering the lawn and not the sidewalk or driveway – to avoid water waste and runoff.
  • Keep track of drought by following the U.S. Drought Monitor, a website managed by the University of Nebraska, which is updated each Thursday.  (The map below is from Oct. 2016, when much of MA was in severe to extreme drought.)
  • Always follow town watering restrictions for public health and safety.

Maintain irrigation systems

  • Maintain irrigation systems on a regular basis to catch leaks and ensure even distribution of water.
  • WaterSense certified irrigation professionals are available to keep your system working efficiently.
  • If you have an irrigation system, update to a moisture sensor that will turn on your system when actually needed, as opposed to watering on a regular schedule, regardless of conditions. The irrigation moisture sensor measures the water content in soil and regulates irrigation systems based on the moisture results.  The moisture sensor signals the irrigation controller to turn on the system, based on when a lawn actually needs water, as opposed to on a variable schedule.  This device takes the guess work out of irrigating, and minimizes errors, such as watering during a rain storm.

To save even more water in your landscape

  • Reduce the amount of grass in your yard by planting native shrubs and native ground cover plants, or by creating patios and walkways with pervious materials, such as pavers, bricks, or crushed stone.
  • Landscape with drought-tolerant native plants to reduce water use by 20-50 percent.
  • Plant according to the various zones in your yard (hot/sunny, cool/shady, moist, dry, etc.)
  • Leave a border of un-mowed native plants along a stream or pond on your property
  • Use only minimal fertilizers or other chemicals on your property

Test your lawn by stepping on a patch of grass; if it springs back, it doesn’t need water.

Healthy topsoil is essential

  • Create a layer of rich, organic loam 6” to 8” thick to retain moisture, encourage deep roots, and harbor beneficial earthworms.
  • Supplement topsoil by letting grass clippings and shredded leaves decompose on your lawn.
  • To build topsoil faster, apply a thin layer of rich loam or compost once or twice a year.
  • Create compost for use on the lawn and in your garden. Add leaves, weeds, fruit and vegetable wastes, and crushed eggshells. Avoid meats and high-fat items like peanut butter that attract pests. Learn how to compost.

Mowing tips

  • Cut it long. Set mower to its highest setting. Taller grass shades the roots and slows evaporation.
  • Mow regularly. Remove less than 1/3 of the grass when you mow.
  • Sharpen mower blades. Dull blades shred grass instead of slicing it.
  • Tolerate clover. Clover adds nitrogen to the soil.

Use the right grass seed

  • Over-seed with drought-hardy, native perennial grass seed in early September, to crowd out weeds. Apply compost or dehydrated manure on newly seeded areas, especially bare spots, to hold moisture and help establish new grass.
  • Avoid pesticides. They kill beneficial earthworms. If grubs become a problem, apply milky spore. Once established, milky spore can protect against grubs for years!
  • Aerate your lawn. Aeration improves drainage, allowing your lawn’s root network to absorb more water.


Fertilizers—nitrogen and phosphorus—are good for plants but not for water quality. In ponds, streams and rivers, fertilizers are pollutants that harm fish and wildlife, can cause smelly algae blooms, and can even affect drinking water.

  • Recycle grass clippings with a mulching mower. Clippings are a free, natural fertilizer—and all that most lawns need.
  • Sweep or blow grass clippings and fertilizers off of pavement, and away from storm drains and wetlands.
  • Never fertilize before a heavy rainstorm (light rain is ok).
  • Use slow-release or natural organic fertilizers instead of chemical fertilizers.
  • Don’t apply fertilizer with phosphorous to an existing lawn. It’s illegal in MA unless a soil test says you need it.
  • Choose fertilizers with 75-100% “slow-release” or “water insoluble” nitrogen.
  • Get your soil tested before you fertilize at the UMass Amherst’s Soil Testing Lab.

Learn more about fertilizers at