Soap as a wetting agent for herbicides

Updated July 19, 2017

Using soap as a wetting agent is a secret that is unknown to many gardeners. They have a love-hate relationship with the rain. Gardeners need the rain for the plants to grow, but this watery friend washes off the herbicides, insecticides and fungicides that the gardeners have spent hours applying to their vegetables and fruit trees. Well, here is some good news for gardeners everywhere. Mix dish soap with the garden and tree sprays. Alleviate the frustration of having to spray every week or following every downpour of rain.


A wetting agent is a substance sometimes known as a spreader-sticker that reduces surface tension and is used as an additive in garden sprays, enhancing their effectiveness. Soap is a wetting agent that does increase the effectiveness of garden sprays.


The purpose of using common dish soap as a wetting agent is to make the garden spray smooth, reducing the surface tension, which allows the spray to completely cover a leaf's surface. The liquid can spread out instead of beading in drops.


Using soap as a wetting agent will be effective up to ten days, depending on the amount of rain during that period of time. On average, commercial spreader-stickers will last five to seven days longer under the same conditions.


Using soap as a wetting agent aids the insecticide in penetrating the insects' bodies, and it protects the herbicides, insecticides and fungicides from the cleansing effects of rain. Because of these attributes, the gardener doesn't have to spray as often.


Spreader-stickers sold in a nursery are inexpensive and tend to be slightly more effective than dish detergent. If the dish detergent is biodegradable and the spreader-stickers available at the nursery are not, with the few days' difference in effectiveness, using soap as the wetting agent would be more eco-friendly.

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About the Author

Karen Seelenbinder began writing professionally in 2007 with the publication of her first children's picture book, "The Wall They Could Not See." Based in Columbus, Ohio, she writes human interest stories for "Abec's Small Business Review." Seelenbinder has a Bachelor of Music from Bowling Green State University.