Is Killing Aphids With Soapy Water Safe And Effective?

Question: Can you kill aphids with soapy water?

Answer: Yes, soapy water is an environmentally friendly pesticide that will kill different species of aphids on plants and general pest control.

Pest control on plants. Spraying aphids on the leaves in the home garden. Protection against insects in agriculture and gardeningPin
Spraying soapy water is an easy way to kill aphids | Skorzewiak-DepositPhotos

So, does soapy water kill aphids?

The basic organic insecticide garden recipe consists of one or two teaspoons of dish soap (preferably pure castile soap, such as Dr. Bronner’s or Dawn dish soap) in 1 quart of water to make an aphid spray.

If you have a lot to spray, mix 5 tablespoons of soap per 1 gallon of water. To keep the right aphids soapy water ratio, keep in mind that too high concentrations of soapy water can burn plant foliage.

Put the mixture in a spray bottle to apply this aphid spray by wiping it onto plant leaves, buds, and stems or by spraying.

Vigorous spraying of the affected plants will kill aphids on contact and knock them off the plant.

How long does it take for soap to kill aphids?

Generally, when sprayed directly on aphids, soapy water can start to kill them within minutes to hours.

However, it may take longer for the soap to completely eliminate all aphids, especially if the infestation is large or the aphids are hiding in hard-to-reach areas.

It’s important to thoroughly coat the aphids with the soapy water solution and ensure it reaches all parts of their bodies to increase the effectiveness of the treatment.

The insecticidal soap drys up the waxy coating of soft-bodied insects like aphids without doing harm to the plants, natural predators, and beneficial insects such as bees, lady beetles, lacewings, and parasitic wasps. [source]

What Is The Best Soap For Killing An Aphid Infestation?

Aphids are common sap-sucking insect bugs that hide and feed on a plant’s leaves, leading to yellowed leaves, twisted and curled leaves, stunted growth, dead shoots, and poor plant growth. 

Pure castile soap, such as Dr. Bronner’s, is the right kind of liquid soap to control aphid populations.

Many pest recipes call for liquid dish soap, and this is right if the product you choose is soap (not detergent).  Dawn dish soap for aphids is a popular option.

An aphid spray using soap made with animal fat or vegetable oil works to smother aphids. Detergent does not contain oils and can damage your plants.

Related: Using Castile Soap For Aphids | What Time Of Day Should You Spray Aphids?

Another alternative is adding ingredients like garlic extract or cayenne pepper to your soapy water mixture. This will repel aphids, as they cannot tolerate the smell of garlic.

Gardener spraying plants for fungus with Neem oilPin
Spraying plants for fungus with Neem oil | focusandblur-DepositPhotos

What Is The Best Way To Apply Soapy Water For Aphid Control?

Once you’ve mixed up your soap and water solution, do a spot test of your aphid soap spray to ensure the solution will not hurt your plants. This is especially vital when dealing with succulents.

This is because high concentrations of soap water for aphids can burn plant foliage.

Dab or spray a single leaf and wait a full 24 hours to make sure the plant will not react negatively.

If all goes well, water your plants thoroughly before applying the solution. Consider giving your plants a vigorous shower before spraying to knock off as many aphids as possible before the treatment.

How Do You Apply Soap And Water Spray To Kill Aphids?

  • Completely drench your plants.
  • Spray every bit of the plant, including nooks and crannies in stems and the undersides of leaves.
  • This treatment will only kill and get rid of aphids on contact.
  • If they manage to escape, they will quickly reproduce.

When Is The Best Time Of Day To Treat Plants For Insect Pests and Aphids?

Horticultural soap works well in aphids and other common insect pests, such as ants, cabbage worms, caterpillars, Japanese beetles, spider mites, whiteflies, mealybugs, thrips, and grasshoppers. 

Anytime you spray plants with anything, wait for a cool, still time of day. Morning is best when temperatures are above 60° degrees Fahrenheit.

Aphids do not begin to hatch until temperatures average 60° degrees Fahrenheit.

Spraying early allows the foliage time to dry out on a sunny day before nightfall. Being wet overnight can cause problems with fungal infection.

potato aphid on leaf, check out the  cornicle on the aphids backendPin

For Organic Pest Control, How Many Times Should I Spray For Aphids?

Soap and water spray do not kill aphid eggs. A few survivors can quickly repopulate your plants. Spray once or twice a week for a month to six weeks. Spray again after any rainfall.

Is It Better To Spray The Soap Solution for aphids Or Wipe It On?

If you are in an area where you can spray liberally without making a mess or causing damage, spraying is best. Vigorous spraying will kill aphids on contact and will also knock them off the plant.

For delicate plants or areas where spraying is prohibitive, wiping houseplants with a wet cloth will work.

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