How to prepare a soap solution against spider mites? - briefly
Mix 1–2 teaspoons of pure liquid soap into one gallon of water, stir until fully dissolved, and spray the solution onto all surfaces of infested plants until wet, repeating every 5–7 days. Test the mixture on a small leaf first to confirm the plants tolerate it.
How to prepare a soap solution against spider mites? - in detail
A practical soap spray for spider mite control requires precise proportions, proper mixing technique, and safe application methods.
Begin with a pure liquid soap that contains no additives such as fragrances, dyes, or moisturizers. A castile or potassium‑based soap works best because it dissolves readily in water and leaves minimal residue on foliage. Measure 1 teaspoon (approximately 5 ml) of the soap per 1 liter of water to achieve a 0.5 % solution, which is strong enough to disrupt the mites’ cuticle without harming most plants.
Add the measured soap to a container of lukewarm water. Stir gently until the soap is fully dispersed; avoid vigorous shaking that can create foam, which reduces the amount of active ingredient contacting the insects. For larger volumes, scale the ratio proportionally (e.g., 10 teaspoons per 10 liters).
Optional adjuvants can improve coverage:
- 1 ml of horticultural oil per liter to enhance leaf wetting.
- A few drops of a non‑ionic surfactant if the spray tends to bead on waxy surfaces.
Transfer the solution to a clean spray bottle or pump sprayer. Apply in the early morning or late evening when temperatures are below 30 °C and sunlight is low, preventing rapid evaporation and leaf scorch. Thoroughly coat the undersides of leaves, where spider mites commonly reside, and repeat the treatment every 5–7 days until populations decline.
Safety precautions include wearing gloves and eye protection, labeling the container clearly, and storing the mixture in a cool, dark place for no longer than two weeks. Discard any solution that develops odor or discoloration, as this indicates degradation of the active components.
If leaf damage appears, reduce the soap concentration to 0.25 % (½ teaspoon per liter) and increase the frequency of applications. For resistant mite populations, alternate the soap spray with a neem‑oil or insecticidal‑soap product to prevent adaptation.