Issue: April 16
Cleaning water with vinegar can damage lawn unless diluted.
Q. Can "used" water containing vinegar be safely used on the lawn without hurting the grass? We use vinegar in water to clean certain areas such as floors, etc.
via NMSU College of Agriculture web site
A. Vinegar is useful as a cleanser because it can be used to clean grease and oil, which can be a problem for plants. If there are no other materials in the water (soaps, detergents, or other chemicals), disposal of used vinegar cleaning solutions should cause no harm if done properly.
Vinegar is a degreaser and it will remove the waxy cuticle from the grass leaves. This will cause the leaves to dry. However, if you greatly dilute the vinegar solution before disposing of it in the lawn, or if you irrigate the lawn immediately after disposing of the vinegar, you should cause little or no harm to the grass. Because vinegar is an acid, it can help release nutrients in the soil and can be beneficial, but it can also harm plants if it is too strong. Some people use a few tablespoons in a gallon of water to acidify the water for houseplants, but if it is too strong, it kills the plants.
You can purchase some pH test strips online and perhaps from local science supply stores (items sold for students' science fair projects). These test strips change color when dipped into solutions of different acidity levels. The color change helps you determine the acidity of the solution in which it is dipped. A pH above 4 or 5 should be safe for your lawn and acid loving houseplants. Irrigation after application is still a good safety measure. Do not apply vinegar or fertilizer to dry soil, moisten the soil first.
You should test disposal of vinegar solutions in areas of the lawn that are not critical to the appearance of the landscape. Test in both sunny and shady areas because you may get different responses in these areas. When you have found a safe dilution level, you can dispose in larger, more obvious areas. Do not use the same area too frequently and expect changes in the response of the grass as it becomes hotter in the summer.
For more gardening information, visit the NMSU Extension publications World Wide Web site at http://aces.nmsu.edu/pubs/_h.
Send your gardening questions to:
Yard and Garden, Attn: Dr. Curtis Smith
NMSU Agricultural Science Center
1036 Miller Rd. SW
Los Lunas, NM 87031
Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist with New Mexico State University's Cooperative Extension Service. NMSU and the U.S. Department of Agriculture cooperating.