Keep the Peace Between Soil and Water

You might gather from the title that there’s a chance soil and water don’t always get along, and you would be correct.

Dry soils or dry potting soil mixes will actually repel water, as they’ve become hydrophobic. We want them to be hydrophilic, aka water loving.

Products known as wetting agents will help bring back that loving feeling to dry soils, allowing water to enter the soil easily and reducing runoff. More importantly, water-loving soils retain more water, thus reducing the need for frequent irrigation.

Some common wetting agents include:

  • Non-ionic surfactants – natural or synthetic chemicals that reduce the attraction between water and soil molecules. Organic enthusiasts can try humic acid, one of the ingredients in HastaGro.
  • Humectants – chemicals that cling to root systems and absorb water vapor. Hydretain is a common one.
  • Polymers – synthetic polymers called polyacrylamides and polyacrylates. Similar to humectants. You could try Soil Moist and American HydroSoil.
  • Soaps and saponins – natural agents similar to non-ionic surfactants. Products can be made from plants like yucca, Soapberry and Soapbark. One example is Yuccah by Plant Health Care, Inc.
  • Microbial products – organic goods like compost leachate and compost tea.

Many golf courses swear by these products. Since their business is to keep everything green without breaking the bank, there must be some validity to a wetting agent’s ability to reduce watering needs.

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Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
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