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How to Water a Lawn With Soft Water

Although you may enjoy soft water for bathing and other household uses, it’s not good for your lawn and garden. Hard water contains magnesium and calcium, which counteracts any sodium found in the water (a substance that can cause a harmful build up in the soil). On the other hand, water softener adds sodium to the water, replacing magnesium and calcium. Medium and high levels of sodium in the soil make the earth unable to clod. The earth becomes flaky, which in turn leads to poor water penetration–a condition that prevents plants and turf from obtaining adequate oxygen. Fortunately, if you have soft water, there are simple steps you can take to protect your lawn and garden.

Check your water first to make sure it’s truly soft. An easy way to do this is place your hands inside a sink of water. Once they are fully wet, put a quarter-size dollop of liquid hand soap on your palm. Rub your hands together. If you can get a frothy lather, your water is soft.

Ask your city water department about the quality of your water if you’re unsure about your hand washing test. Alternatively, contact your county extension office to test your water. Be sure they know you’re simply interested in how soft or hard your water is. According to the Water Quality Association of the United States, soft water contains dissolved hardness minerals below 1 GPG (grain per gallon).

Apply agricultural-grade gypsum to your lawn twice a year to help counteract the effects of soft water. Apply at a rate of 2.5 pounds per 100 square feet. Gypsum is available through feed and farm stores and some gardening centers. Water in well.

Continue watering the lawn as usual. Eventually, the gypsum will dissolve and counteract a build up of sodium in the soil.

Remove outdoor faucets from your home’s water softening system if you use one. This eliminates the need to spread gypsum twice a year.


If you have soft water, your plants will also require special treatment. Twice a year, apply gypsum (0.75 ounces for every square foot) to garden beds or any area that gets watered. If you have a well, you’ll need to test your water every year for bacteria. At that time, you can also reassess the softness of your water.

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