At some point, all gardeners have to deal with an insect invasion. Fortunately, there’s an easy trick for destroying destructive insects: homemade insecticidal soap!
An insecticidal soap spray is simply a mixture of fat-based soaps and water. That’s it! Then, you spray the mixture on the plants’ leaves, and on the tiny pests that devour them. The soap dissolves the membranes of the insect’s body, killing them through excessive water loss.
Insecticidal soap is a 1-2% solution of soapy water. That said, most commercial blends err on the safe side with a 1% solution. This amount is safer for wilted, unhealthy plants, but less effective. In your homemade solution, try for a 2% solution.
Choosing the right soap is essential, since detergents like dish or laundry soap won’t work. Castile soap like Dr. Bronner’s or Fels Naptha are ideal. Shop around for the brand that works best for you.
Lard-based or goat’s milk soaps would works as well. The important thing is to make sure that the soap you use is fat-heavy. The fats in the soap are what kill your pests.
Make sure the soap you choose is pure soap. Don’t pick a product with added skin softeners, chemicals, or grease cutting power. These additions make the soap less effective as an insecticide.
Decide how much insecticidal soap you need. If you’re adding in neem oil, mix up small batches. After 8 hours mingling with soap and water, the properties of the oil start to break down.
For a gallon of spray solution mix:
1 gallon water
5 tablespoons soap
1 teaspoon optional efficiency booster (neem, garlic, cayenne, or vinegar)
For a quart of spray solutions mix:
1 quart water
¾-1 tablespoon soap
¼ teaspoon optional efficiency booster
Shake the solution very well. If the resulting solution seems too strong, add a cup (for each gallon), or ¼ cup (for each quart) water to reduce the concentration.
Homemade insecticidal soap is bee, butterfly, and beneficial insect safe. Friendly bugs like bees, ladybugs, and butterflies have a thicker, stronger outer skin that fatty soaps can’t dissolve. So they stay safe.
Insecticidal soap works well against the soft-bodied invaders. Mealybugs, aphids, spider-mites, and thrips.