Dish Soap Spray
Using soaps as an insecticide has been in practice for over 200 years because of its low cost and reduced environmental impact, though little is actually known about how soaps work to kill insects. It is thought to disrupt the cell membranes inside the exoskeleton (outer shell) interrupting normal cell function resulting in death. Another possibility is that soaps remove a waxy coating that most insects have on their exoskeleton. The waxy coating helps to prevent moisture loss so when it is compromised insects experience extreme dehydration.
Soaps are a contact insecticide meaning that it must be applied directly to the insect and as thoroughly as possible. A soap spray is not residual in terms of being an insecticide and will not affect any insects not contacted by it. Plants should be rinsed after spraying an infestation especially if it’s edible.
Soaps can strip the waxy, protective coatings from a plants leaves the same way it breaks down an insects'. Damage can occur to delicate plants even with the most gentle soap so use caution. It’s important to remember to use only gentle soaps, not detergents like dishwasher powders and laundry soaps. The fewer chemicals a soap has in it the better. Never use soap directly on a plant, make sure it’s always diluted. It’s best to test it on a small area 24 hours in advance to see if it has a negative impact on the plant.
To make Dish Soap Spray you will need:
- 10 ml of a gentle dish soap (2 most recommended are Dawn and Ivory)
- 5 ml of oil (olive oil works best)
- 1 liter of filtered water
- Spray bottle
Where to start:
- It's easiest to mix the ingredients in a separate bowl
- Transfer the mix to your spray bottle
- Use where needed
Using Dish Soap Spray:
Dish soap spray, as was mentioned before, is a contact insecticide and works only when applied directly to insects. Make sure to coat the infested area thoroughly and let soak for a while. Rinse the area and repeat until signs of the insects disappear.
Soaps work on some insect but on others it will have limited effect, if any effect at all. Luckily this mix is so cheap to make that there is really no harm in testing it out on an infestation before resorting to more drastic, expensive measures.
- Don’t spray plants on bright, hot days because the sun’s rays can be magnified through the soap and water mix causing burning or worse.
- Remember to always test it on a small area first.
- Rinse plants before consuming if they are edible.