With kids and pets ripping through the house like a runaway stampede, the last thing a frazzled mom needs to worry about is dangerous pesticides within easy reach of her family. You can’t win arguments with invading insects, so you’ve got to treat infested houseplants with something that annihilates bugs. Meanwhile, that “something” can’t be dangerous to little fingers that might come into contact with the treated plants. Make a safe, effective solution to kill bugs in houseplants with the old-timey stuff your grandma may have used for practically all her cleaning tasks. You can use gentle, harmless Castile soap to salvage bug-ridden plants -- as well as your sanity.
1 Water your buggy houseplant the day before you treat it with the homemade solution.
2 Pour 2 cups of water into a plastic spray bottle. Add 1 tablespoon of liquid Castile soap. Invert the sprayer gently five or six times to combine the soap and water without creating excessive suds. Use the solution the same day.
3 Set the affected houseplant in the shower. Spray all the plant’s surfaces to coat them thoroughly with the solution, but not enough to produce runoff. Pay special attention to the undersides of the leaves, where bugs like to run and hide.
4 Leave the plant in the shower to allow the soap to do all the dirty bug-killing work for you.
5 Rinse all traces of the soap off the houseplant two or three hours later to minimize the possibility of leaf injury.
6 Discard any leftover insecticidal soap solution.
7 Repeat the treatment five or six days later. Re-treat houseplants immediately if new bugs arrive.
Items you will need
- Plastic spray bottle
- Liquid Castile soap
- Glass jar
- Distilled or rain water (optional)
- Immediately after mixing, test the bug-killing solution for water hardness. Hard water contains magnesium, calcium and iron, which combine to turn soap to scum, rendering the solution completely ineffective against pests. Pour a small amount of the solution into a glass jar and stir. Let the solution sit for 15 to 20 minutes. If it still looks slightly milky with a uniform consistency, your tap water is fine and you have a winner. If scum has begun collecting on top, your water is too hard to use for insecticidal soap. Throw the batch out and make a fresh one with distilled water or rainwater.
- Always test a small spot on one leaf before applying any insecticide to your houseplant. Check for burned tips, brown or yellow spotting, scorching or other signs of distress after 24 hours.
- Insecticidal soap works well against pests such as adelgids, aphids, caterpillars, crickets, earwigs, fleas, flies, grasshoppers, lace bugs, leafhoppers, mealybugs, mites, psyllids, sawflies, scales, spider mites, spittlebugs, springtails, thrips and whiteflies.
- Castile soaps are natural, plant-based, biodegradable and less likely to harm your plants than other soaps and all detergents. This soap won’t hurt beneficial critters such as honeybees, parasitic wasps and ladybugs.
- Any soap or other pesticide can cause toxic reactions in some very sensitive houseplants. Always initially test those you’ve never treated with soap before. Do not use soap on any plant with hairy leaves.
- Soaps can be harmful to soft-bodied beneficial predators such as the larvae of syrphid flies, as well as to some predatory mites. Once the soap solution is dry, it no longer poses a danger to any insect creatures.
- University of Connecticut Extension: Insecticidal Soap
- Colorado State University Extension: Insect Control: Soaps and Detergents
- Fine Gardening: 35 Pest and Disease Remedies -- Red-Pepper Powder Repels Pesky Critters
- Washington State University Spokane County Extension: Insecticidal Soaps
- University of Rhode Island: Least Toxic Pesticides
- University of Florida St. Lucie County Extension: Home Remedies for Insect and Disease Control on Plants
- University of Florida IFAS Extension: Clean Up Pests With Soap
- Washington State University WSU Extension: Guidelines for Insecticidal Soap
- No-Dig Vegetable Garden: Organic Garden Pest Control
- Mother Earth News: Organic Pest Control: What Works, What Doesn’t
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