Does Tide Detergent Hurt Landscaping?

Soaps and Detergents

• The plain soaps recommended as surfactants for homemade bug killers are based on animal or vegetable fats and oils, broken down with heat and treated with alkalis to form the anionic surfactant known as soap. Detergents like Tide use petrochemicals in addition to organic fats and oils. They also use chemicals including sulfur trioxide, sulfuric acid and ethylene oxide to reinforce their effectiveness, especially in hard water. Up to 30 percent of Tide detergent is made up of these harsher chemicals, including alcohol ethooxyslfate and benzene sulfonic acid, abrasives such as silicate, and oxidyzers such as sodium carbonate peroxide -- all of which will affect plants as well as the bugs that eat them.

Tide vs. Bugs

• Tide helped reduce populations of aphids, citrus red mite, psyllids and greenhouse thrips on some landscape plants in a controlled study. It killed bugs by contact, dessicating and destroying living tissues. Once it dries, though, insects can shake it off -- so liquid must be re-applied for continued effectiveness. Tide is not approved by the EPA nor is it labelled for use as a pesticide.

Effects on Plants and Soils

• Detergent's cationic, or positively charged, compounds are toxic to plants, even at the 1-to-100 dilution rate approximated in the suggested teaspoon-per-gallon mixture. At higher concentrations, surfactants penetrate plant surfaces, damaging cells and inhibiting photosynthesis, leading to plant deformation and mutation. Chemical surfactants destroy the surface layer of cells on roots, limiting their ability to gather nutrients from the soil. Sensitive landscape plants such as ferns, palms and many flowers might end up as dead as the aphids that plague them. According to Tide's material data safety sheet, a 1 percent solution with water has a pH of 10 to 11.5, a moderate base reading. Although it might take many repeated applications to alter soil pH permanently, plants that grow best in a slightly acidic to neutral soil can suffer from fluctuations when Tide drenches soil.

Reserve Tide for the Laundry

• Although some older studies found that plants produced as well or better with soap-based pesticides, this resulted from the presence of phosphates -- chemicals that were eventually banned due to their pollution-causing potential. More recent studies have found that use of household products like Tide on plants inhibits growth. Insecticidal horticultural soaps, using only animal fats and vegetable oils, contain gentle surfactants and organically derived pesticides in pre-mixed sprays or concentrates -- one product dictates mixing 5 tablespoons of concentrate per gallon of water -- and work without harsh detergents.