Dish Washer Liquid as an Insect Repellent for Plants

Dishwasher Liquid

• Dishwasher liquid detergent contains compounds called surfactants. Also found in cleaners like liquid bleach, surfactants help dishwashing liquid penetrate organic matter. This makes it more effective at removing oil and dissolving food particles because it can work on them on the inside and outside at the same time. Surfactants also work on bugs with soft bodies, like bees, caterpillars and gnats. They help dishwasher liquid get inside of the insects, thus dehydrating and poisoning the bugs.

Use

• To use dishwasher liquid detergent against bugs, pour 4 tbsp. of soap into a plastic spray bottle. Fill the bottle the rest of the way with water and shake it up to distribute the detergent throughout the liquid. Spraying it directly onto a bug will kill it. To use it as an insect repellent on plants, lightly spritz down the leaves of the plant you want to protect. Only apply the solution every 10 days. It will kill insects it touches and keep others away.

Drawbacks

• Dishwasher liquid detergent is more effective at killing insects than it is at repelling them. Take care not to over-apply it, either by soaking a plant’s leaves with the solution or by applying it too frequently. The surfactants that kill bugs can also get inside a leaf’s waxy outer layer, causing damage to the interior. Avoid using it in very sunny or hot weather; the soap can dry out a plant’s leaves, making it more vulnerable to dehydration and sun damage.

Considerations

• If you want to protect your plants from future insect damage rather than killing those that are currently causing problems, add another ingredient to your solution to supplement the dishwasher liquid detergent. Smash a few garlic cloves and add them to the spray bottle. Garlic oil is a natural insect repellent. Using it allows you to reduce the amount of dishwasher detergent to 2 tbsp. from 4 tbsp., which is safer for your plants.