Dish soap makes a safe, effective homemade insecticide, the same as insecticidal soap.
Refuted
Dish soap isn't the same as insecticidal soap — detergents strip the leaf's protective wax and can burn foliage, so the "safe homemade spray" idea backfires. It does kill some soft-bodied pests, but if you want a soap spray, use a real insecticidal soap made not to harm the plant.
What is actually known
A soap spray can kill soft-bodied insects (aphids, mites) on contact, but dish detergents are not insecticidal soaps. Detergents are degreasers: they dissolve the waxy cuticle that protects the leaf, so repeated or strong sprays cause phytotoxic burn, especially in heat or sun — the "safe homemade version" framing is exactly backwards. True insecticidal soaps are specific potassium-salt fatty-acid formulations tested not to damage foliage. If you use a dish-soap spray at all, it is a weak, dilute, rinse-after last resort, not an equivalent.
Evidence: not yet confirmed against its 1 source.
what this rests on - one pointer
University of Connecticut Home & Garden Education Center, 'Insecticidal Soaps' (homegarden.cahnr.uconn.edu/factsheets/insecticidal-soaps, read 2026-07-14): 'Dishwashing soaps and detergents are designed to remove grease from dishes and may cause plant damage by dissolving the waxy cuticle on plant leaf surfaces'; 'Insecticidal soaps are potassium salts of fatty acids' — so dish detergent is neither the same as nor a safe substitute for a formulated insecticidal soap.
When would that grow at your place? →
Cite this page
Milpa Gardens. "Dish soap makes a safe, effective homemade insecticide, the same as insecticidal soap." Evidence grade: Refuted. https://milpa.garden/beliefs/dish-soap-insecticide-soap-spray-bugs/
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