Insecticidal Soap
Quick Facts
- Type
- Fatty acid salt
- Source
- Potassium salts of fatty acids derived from plant oils
- OMRI Listed
- Yes ✓
- Bee Safe
- Yes
- Pet Safe
- Yes
- Residual
- No residual — only kills on direct contact while spray is wet
- Best For
- Aphids, whiteflies, and spider mites on vegetables and ornamentals. Safe enough for daily use if needed.
What Is Insecticidal Soap?
Disrupts the cell membranes and removes the protective waxy coating of soft-bodied insects, causing rapid dehydration and death on contact. No residual activity — must hit the insect directly.
Source: Potassium salts of fatty acids derived from plant oils
What Pests Does Insecticidal Soap Kill?
Insecticidal Soap is effective against the following pests:
How to Apply Insecticidal Soap
Best for: Aphids, whiteflies, and spider mites on vegetables and ornamentals. Safe enough for daily use if needed.
Avoid for: Hard-shelled insects (beetles, mature scale), large caterpillars, and drought-stressed plants.
Residual activity: No residual — only kills on direct contact while spray is wet
Safety Profile
| Category | Rating |
|---|---|
| Bee Safety | 🟢 Safe for bees |
| Pet Safety | 🟢 Safe for pets |
| Overall Rating | Safe — Safe for kids, pets, and bees when used as directed |
Why Isn't Insecticidal Soap Working?
If Insecticidal Soap isn't delivering results, check these common failure modes:
Missed coverage — spray must contact the insect body directly
Hard water reduces effectiveness — use distilled or rainwater
Phytotoxicity on sensitive plants — test on a leaf first, especially on ferns, new transplants, and hairy-leaved plants
Wrong soap used — dish soap is NOT insecticidal soap and damages plants
DIY Insecticidal Soap Recipe
Mix 2.5 tablespoons pure castile soap (unscented) per gallon of soft water. Spray directly on insects. Rinse plants with clean water after 2 hours if concerned about phytotoxicity.
Best Insecticidal Soap Products
Safer Brand Insecticidal Soap
ConcentrateThe original — potassium salts of fatty acids
Natria Insecticidal Soap
RTU SprayReady-to-use convenience
Dr. Bronner's Pure Castile Soap
DIY baseUse unscented for DIY insecticidal soap