Is Recycled Water Harmful To Turf And Landscape Plants? May 20, 2014

It certainly can be, but recycled water is not always harmful to turf and landscape plants. Because recycled water contains more dissolved salts and is of poorer quality than drinking water, extra precautions must be taken to use it successfully when irrigating turf and landscape plants. Fortunately, recycled water can play a major role in the management of turfgrasses and landscape plants, particularly in areas where fresh water is in dwindling supply.

Recycled water with high levels of salts, namely chloride, sodium and bicarbonates, can have adverse effects on plant health and appearance when salt accumulation reaches critical levels in either plants or the soil. As a result, when using recycled water, a general rule of thumb is to use 10 to 20 percent more water so that salt accumulation in plant tissues and soil will be less concentrated and salts can leach through the soil. When salt accumulations do reach critical levels in the soil, a heavy watering may be the best approach to flush, or leach, salts downward through the soil profile.

Furthermore, sensitive plants, such as those on golf putting greens, may need to be irrigated occasionally with potable water to meet water needs of the plant without adding salts to the soil. Obviously, appropriate plant selection and good irrigation management can minimize the potential impacts of the salts or specific ions of concern in recycled water. When it comes to soil types, coarse-textured soils such as sandy loams are best for using recycled water because of good internal soil drainage.

Heavier soils, such as clays, may still be acceptable but will require more mitigation strategies and regular monitoring of soil chemical properties. On a positive note, the higher nutrient content of nitrogen, phosphorous and potassium in recycled water can be beneficial to turfgrasses and landscape plants. In some cases, turf and other landscape plants obtain from recycled water all the phosphorous and potassium required as well as a large part of their nitrogen requirement. Sufficient micronutrients are also supplied by recycled water thereby reducing annual fertilizer inputs.

More from the USGA