Dish Soap

You’ve probably read dozens of articles and posts about the wonders of dish soap as a pesticide, fungicide, and surfactant in the garden. All of those posts are wrong.

Dish soap claims
 
Many claim that mixing dish soap with water and spraying it on plants will kill ants, aphids, psyllids, spider mites, thrips, whiteflies, and other garden pests. And it will. In the same breath, those claims assure you that beneficial insects, such as honey bees and ladybugs, are safe from the same actions that kill the pests. How can that be?
 
The fact is that dish soap harms all insects found in the garden. And your plants.

Dish soap is bad for plants

How dish soap works
 
Dish soap is a detergent. Dish soap cleans dishes by cutting grease, oil, and wax. Dish soap generally contains colorants, fragrances, bleach, enzymes, phosphates, and rinsing agents. None of those are good for your plants.
 
Dish soap damages protective, waxy coatings used by plants and insects. If you wash this protective coating away, infection, infestation, and dehydration become more likely.
 
Dish soap v. insecticidal soap
 
Insecticidal soap is not a detergent. It is a soap specifically formulated for use on plants. It must be used properly to be safe and effective. While liquid hand soap is a soap and not a detergent, it contains fatty acids that are phytotoxic (poisonous to plants).

Despite popular opinion, dish soap does not belong in the garden. Save it for your dishes, and your plants will thank you.​