Quick Tip Tuesday: DIY Non-Toxic Insecticidal Soap Spray
Last year I bought a lovely little butterfly weed plant. It’s been sitting in a pot on our back patio. Not too much growth, and occasionally it will put forth a few blooms.
This year, to my delight, it has started sprouting lots of new leaf growth at the base. Yay! Unfortunately, it also started attracting a TON of orange aphids. At first I panicked, but after a little research and a lot of plant and aphid observation, I realized that they really weren’t doing any harm. And all was well.
Until…I started to notice brown, curling, sickly-looking leaves. A peek underneath revealed that these guys had joined the party:
Whiteflies and brown aphids. And they don’t know how to play nice.
I try to keep my gardening as organic and chemical-free as possible, so I didn’t want to use a commercial, chemical-laden pesticide. Insecticidal soaps (also called horticultural soaps) are a nice, chemical-free alternative to strong pesticide products. These soaps are generally effective on soft-bodied insects including aphids, mealybugs, spider mites, thrips, and whiteflies.
While there are commercially-made insecticidal soaps available, it can also be made at home…with some cautions:
- Use a natural, gentle, unscented soap, such as Dr. Bronner’s castille soap. Avoid using dish detergents or hand soaps.
- Use filtered water (I use water from my Brita pitcher). Using hard water can reduce the efficacy of the mixture.
For any insecticidal soaps, commercial or DIY, always observe the following precautions:
- Always test the spray on a few leaves first. Spray thoroughly, wait at least an hour, then check for signs of wilting or browned edges.
- Spray the plant well with water several hours after applying the soap mixture to remove any residue. Using a strong spray of water will also remove the dead pests.
- Spray and rinse plants early in the morning, before the sun hits them full-strength. Strong sun hitting soap-sprayed leaves can result in burning.
- Avoid using on beans, peas, cucumbers, gardenias, ferns, succulents, ivy, tomatoes, azaleas, lantana, and waxy-leaf plants.
And one SuperCaution: if you are trying to encourage butterflies to visit your garden, please always check milkweeds (butterfly weed is a milkweed) and other plants that butterflies utilize for food and egg-laying before spraying with insecticidal soap. It will harm caterpillars and butterfly larvae!!
To make insecticidal soap spray:
- 1 quart filtered water
- 1 1/2 tablespoons pure, unscented soap
- 3-4 drops orange essential oil (optional, but adds insect repelling properties due to the phytochemical limonene which is found in citrus fruits)
Combine all ingredients in a quart jar or other large container. Pour into a spray bottle for use (store extra in a tightly-closed glass jar). Be sure to clearly mark both the sprayer and storage jar.
To use: Spray infested leaves thoroughly, being sure to wet the undersides well. Allow to sit for a couple of hours before spraying the plant well with fresh water. Repeat whenever you see pests return.