Yes you can use soapy water but it should have very little soap in the mix. Natural soap such as Castile is better for the plants. However, I have an entomologist friend who uses one or two drops of a popular blue dish detergent in a gallon of water.
Soapy water can be safe to spray on plants, but it depends on a few factors: Type of Soap: Use a mild, biodegradable soap, such as liquid castile soap. Avoid soaps with additives like fragrances, dyes, or degreasers, as these can harm plants.
While dish soap is often recommended to spray plant pests and diseases, it can damage plants and beneficial insects. Because it is neither “natural” nor “harmless,” it is not recommended for garden use.
Plant Safe Options
Mixing 2 parts water and 1 part vinegar makes a cleaner that will get rid of dirt and grime and any mold or mildew that has accumulated on your siding without harming any of your plants or flowers.
Pure natural castile soap is the best choice for homemade insecticidal soap: it's effective and won't harm your plants. We use Dr. Bronner's liquid castile soap. Peppermint Dr. Bronner's soap provides a further line of defense, since the peppermint aroma deters pests too!
Peppermint, Citrus, and Unscented are all great options. If your water is particularly hard, consider using distilled or filtered so that mineral deposits don't build up on leaves. Combine the soap and water in a spray bottle. Spray plants thoroughly.
Dust plants lightly with a disposable electrostatic or reusable microfiber cloth. Next, wipe both sides of leaves with a soft cloth dipped in lukewarm water. To remove heavy dirt, mix roughly ¼ teaspoon dish detergent in 1 quart of lukewarm water. Spray the plant, then rinse off.
Soapy wash water from dishes or laundry will help keep plants alive in an emergency, but you should be aware of certain possible problems. Chlorine. Bleaches commonly contain chlorine, which can damage plants, particularly if it touches the foliage.
One tablespoon of dish soap or castile soap per gallon of water is enough. Spray with dish soap plus cayenne pepper and/or neem oil. Neem oil sprays are available at most garden centers. Knock them off by hand or a hose and remove the older leaves.
Vinegar is a contact herbicide, so you can unintentionally kill plants in your garden if you accidentally spray them with vinegar. Using vinegar as a weed killer works best on newer plants. "On more established plants, the roots may have enough energy to come back even if the leaves you sprayed have died.
While some types of salts can be beneficial to plants, sodium bicarbonate is not on the preferred list. Baking soda has a drying effect and it is non-selective, meaning it can kill any plant it comes into contact with, including your lawn, flowers, and vegetables, if used incorrectly.
Insecticidal soap -- also known as horticultural soap -- is a non-toxic, environmentally healthy treatment for some types of soft bodied pests such as aphids, whiteflies, spider mites, and mealybugs. It can also help eliminate sooty mold, honeydew, and other leaf fungi.
Sensitive plants include portulaca (Portulaca grandiflora), hawthorn (Crataegus spp.), sweet pea (Lathyrus odoratus), cherries (Prunus spp.), plum (Prunus spp.), horse chestnut (Aesculus hippocastanum), mountain ash (Sorbus spp.), Japanese maple (Acer palmatum), bleeding heart (Lamprocapnos spectabilis), maidenhair ...
A non detergent soap is a naturally made soap with oils or fats, without any other synthetically made or petroleum based detergents.
Dishwashing liquids are primarily designed to dissolve grease from dishes and clean clothes, not to kill insects. Dish detergents may dissolve the protective waxes on the plant leaves.
The University of Minnesota experts recommend a 2% dish soap solution. That means 2 teaspoons of Dawn dish soap per pint (16 ounces) of water. Use a spray bottle to saturate the plants in peril, and make sure you cover it completely. For sooty mold, spray your homemade concoction all over the plant.
Giving your houseplant a bath
Common insects can be controlled with regular bathings or washings once a month. Mix a little dish soap with water and wash leaves and stems of the plant. Make sure to wash the underside of the leaves as well as the top. Insecticidal soaps formulated for houseplants also work well.
Mild, non-toxic soaps, like those in insecticidal soaps for pest control, usually don't cause significant harm. But if the soap has harsh chemicals, such as detergents, chlorine, or degreasers, it could potentially hurt or even kill your plants.
It turns out that soap and alcohol—the two main ingredients in Dawn Powerwash—are both great at killing insects. The soap clogs up insects' breathing tubes, essentially drowning them. Alcohol dries them out as well.
2.5 tablespoons of liquid dishwashing soap (preferably Dawn or Lemon Joy) and not automatic dishwasher soap Mix with 2.5 tablespoons of vegetable oil per gallon of warm water. Make only what is needed for one day's treatment. An insecticidal soap like this is generally not harmful to plants, animals or humans. Mr.
Although you do not have to rinse off the soap after using it, it might be beneficial for you to do so. However, you shouldn't rinse right away.