How To Use Insecticidal Soap On Houseplants

There are various ways that soapy water insecticides for plants operate. To begin with, the exoskeletons of these insects are dried up by the soaps, which leads to cell collapse.

The bug then suffocates as a result of the oils in insecticidal soap preventing bugs from breathing. But particularly which bugs can you manage using this method?

Which Pests Can Be Controlled With Insecticidal Soap?

With this kind of product, some pests can be rather well controlled. Additionally, some pests are comparatively resistant to insecticidal soap. The following are some pests you can manage:

  • Earwigs
  • Mites
  • Thrips
  • Scales
  • Fleas
  • Chiggers.

Scales and caterpillars, which both munch their way through plants, are less resistant to this method of gardening care.

Additionally, some plants should not be treated with insecticidal soaps. Gardenias, peas, ferns, cucumbers, and beans are a few examples. These are all more vulnerable to harm from soaps.

How To Apply Insecticidal Soap To Control Pests

You will apply the product to your plants in the same manner regardless of the kind of bug you want to control. Make sure you have a garden sprayer on available because you’ll need it to apply the soap.

For most gardeners, using a readymade insecticidal soap is the simplest and most practical option, but you can also manufacture your own with store-bought soap if it doesn’t contain any additives. Later, we’ll go into greater detail on how to produce your own insecticidal soap.

Some gardeners increase the spray’s effectiveness by adding additional oil (about one cup), although this is not required.

Add Bacillus Thuringiensis For A Boost

However, if you also need to prevent or cure fungus infestations or other pest infestations that aren’t managed by insecticidal soap, you can always add additional ingredients like bacillus thuringiensis or copper fungicide.

The solution’s effectiveness won’t last indefinitely, so make plans to apply it right now. Spray the tops and bottoms of the leaves, ideally concentrating on any visible insects.

Before using the spray on the entire plant, test it on a few leaves. It’s crucial to remember that insecticidal soap requires contact with the pest in order to be effective, unlike other pesticides.

Applying it while it’s raining outside will give you the best results. As a result, you should spray plants early in the morning or late at night. In this manner, the solution won’t evaporate as quickly as it may in the summer.

How should I apply insecticide soap to my indoor plants?

  • Never spray when the sun is directly on the foliage or when the temperature is above 90 F to prevent scorching plant leaves. (32 C.). The optimum times are typically in the mornings and nights.
  • To avoid spray drift, avoid spraying when the wind is blowing.
  • Use the flimsiest solution you can. If the milder solution fails, only then should the soap content be increased.
  • Spray leaves until the soapy liquid starts to barely trickle. Remember to coat the undersides of leaves as well (where aphids tend to congregate).
  • If lady beetles or other beneficial insects are on the plant, don’t spray. Recheck after a couple of hours.
  • Only use insecticidal soap spray after thoroughly hydrating and watering the plant. Plants that are wilted are more vulnerable to harm.
  • Apply a small amount of soap to one leaf if you are worried that a plant might be sensitive to it. If the leaf exhibits spotting, browning, or other damage-related symptoms, you’ll know around a day later.
  • Remember that some plants are more susceptible to the effects of insecticidal soap spray, such as ferns, ivy, and palms.

Is it possible to use insecticidal soap on houseplants?

When other organic, non-toxic approaches (such as hand-picking bugs off plants, washing them off with a vigorous blast of water, or introducing beneficial insects to the garden) are ineffective, insecticidal soap is the next step to take in pest control.

Common pests on outdoor plants, such as vegetable gardens and flowerbeds, as well as interior plants, such as potted herbs and other houseplants, are instantly eliminated with insecticidal soap. The same recipe works both indoors and outside.

Commercial versions are easily accessible in the gardening section of your neighborhood home improvement store, but this homemade plant bug spray is worth creating because it is so cheap and simple to make.

Can plants be harmed by insecticidal soap?

Some of the first insecticides that gardeners used were soap sprays; to make an efficient soap insecticide, gardeners would boil water with Fels-Naptha soap. These “traditional” treatments eventually lost popularity as more potent and hazardous drugs took their place. Insecticidal soap sprays, however, have experienced a significant resurgence in popularity today as interest in gardening that is more natural and uses fewer chemicals continues to develop. Most garden centers carry these items, but you may also make your own if you can find the necessary components.

What Is Insecticidal Soap?

Gardeners frequently use insecticidal soap, which is prepared with potassium salts of fatty acids, to control insect and pest infestations on their plants. Sprays of soap are useful against insects with soft bodies like mealybugs and aphids. Plants are not harmed by insecticidal soap.

How often should plants be treated with insecticidal soap?

Spray an even mist of insecticidal soap where garden pests frequently conceal themselves, such as on the main stem of a plant and under leaves. The idea is to evenly cover all plant surfaces with just enough spray to dampen the leaves without letting any solution drip onto them. Peaches, apples, tomatoes, zucchini, and pumpkin may all be sprayed directly with this mixture because it is completely eco-friendly and safe to do so.

If necessary, repeat the application procedure every four to seven days. It’s a good idea to treat plants in the early morning or late evening because insecticidal soap only kills insects when it’s wet. This is because the solution will not evaporate as quickly in the heat of the day.

Does insecticide soap cause leaf burning?

To control insect and mite infestations on houseplants, vegetables, fruits, and ornamentals, insecticidal soaps can be a useful tool. When compared to more conventional pesticides, soaps have fewer potential side effects on the user, beneficial insects, and the environment. Knowing how insecticidal soaps “work,” their method of action, and their advantages and disadvantages are crucial for maximum effectiveness.

Insecticidal soaps are fatty acid potassium salts. When an alkali, such as potassium hydroxide, reacts with fat, soap is created. Fatty acids make up the majority of fats. Commercial products have a combination of chosen fatty acid chain lengths.

Only until the insecticidal soap comes into contact with the pests themselves will it operate. The most popular types of soap are manufactured from fatty acid potassium salts. The fatty acids cause the insect cell membranes’ permeability and structural integrity to be compromised. The insect quickly perishes because the broken cells allow the contents of the cell to flow out. Once the spray treatment has dried, there is no longer any insecticidal activity left behind. On leaf surfaces, insecticidal soaps quickly break down and wash away.

The soft-bodied pests that include aphids, adelgids, lacebugs, leafhoppers, mealybugs, thrips, sawfly larvae (pear and rose slugs), scale insects (particularly scale crawlers), plant bugs, psyllids, spider mites, and whiteflies are the ones that insecticidal soaps work best on. Less effective against bug eggs is insecticidal soap. Additionally, insecticidal soap is less effective against pests with rigid bodies like beetles. Some soaps are advertised as being able to prevent powdery mildew on particular plants.

Soaps are not poisonous to mammals. They may, however, cause minor skin or eye irritation. Insecticidal soaps are non-permanent in the environment, biodegradable, and free of organic solvents. Up until the day of harvest, numerous food crops can be treated with a variety of insecticidal soap formulations.

Since insecticidal soaps only work on contact, as was already noted, there is no residual action after an insecticidal soap spray has dried. An insect won’t be harmed by stepping on or consuming soap-treated plant material if it hasn’t been coated with the spray.

Understanding the biology and life cycle of the targeted pest will help you control it more successfully, just like you would with any contact insecticide. For instance, insecticidal soaps can help suppress azalea lace bug nymphs but have little effect on the eggs of the lace bug. Additionally, the undersides of leaves are home to all stages of the lace bug. Spraying only the upper surfaces will have no impact because the targeted pest will not be exposed to the treatment. The ideal timing for treatment will be determined by routine scouting to identify when the lace bug nymphs hatch from the eggs.

  • On some vulnerable plants, insecticidal soaps may result in phytotoxicity signs like yellow or brown spots on the leaves, burned tips, or scorched leaves.
  • Pest pressure, cultivar, plant vigor, environmental factors, spray concentration, spray mixture pH, as well as time, number, and frequency of applications, can all affect how sensitive a plant is.
  • New transplants, unrooted cuttings, and plants with fragile young growth are more likely to develop phytotoxic symptoms and should not be handled with soap. Stressed plants include those that are exposed to hot (more than 90 F), humid, or dry environments.
  • Avoid applying to delicate plants like sweet peas, Japanese maple, mountain ash, or horse chestnut.
  • Begonia, chrysanthemum, Crown of Thorns, cucumber, delicate ferns, thin leaf evergreens (particularly when stressed or when vulnerable new growth is present), ornamental ivy, palms, poinsettia, redbud, river birch, schefflera, Zebra plant, and some succulents may be sensitive. Numerous plants may also suffer damage to their open blossoms or flowers.
  • Spruce glaucous bloom and grape waxy bloom could both change.
  • When in doubt, only treat a small area of the cultivar; do not treat the full population of plants until at least 24 hours have passed and no phytotoxic (harmful to plants) signs have appeared.
  • In addition to removing oil from dishes, dishwashing soaps and detergents have the potential to harm plants by dissolving the waxy cuticle on their leaf surfaces. When used as a spray, dishwashing soaps and detergents (which are not pesticides) increase the risk of plant damage.

To optimum effectiveness, insecticidal soaps should be used when the environment favors slow drying, such as in the early morning when there is dew present or in the early evening. Avoid using soaps during hot, bright days that encourage quick drying. In order for the soap to work, there must be complete coverage: Spray thoroughly, but don’t go past the runoff point. Follow-up scouting may reveal the necessity for more applications.

Hard water with a high mineral concentration may make insecticidal soap less effective and more hazardous to the treated plants. When the metal ions in hard water, such as calcium, iron, or magnesium, bond to the fatty acids in soap, a precipitate (soup scum) may develop. Avoid using insecticidal soaps near bodies of water since they are poisonous to fish and other aquatic life.

In conclusion, if used correctly and with an understanding of their advantages and disadvantages, soaps can be useful instruments in an integrated strategy to pest management. Be sure to adhere to all label directions.

Even with sound cultural measures, pests and illnesses occasionally do develop. Use of chemical control should only be considered as a last resort.

Department of Plant Science and Landscape Architecture Integrated Pest Management Program UConn Extension

by Leanne Pundt, a University of Connecticut Extension Educator. Updated in 2015.

What is the shelf life of insecticidal soap?

It’s crucial to read the entire label and carefully follow the instructions when applying anything to plants. The usual dosage for insecticidal soaps is 1 to 2 percent (2 1/2 to 5 tablespoons per gallon). Always abide by the instructions on the product’s label. Avoid trying to utilize at higher concentrations because doing so could be exceedingly hazardous. In a fresh sprayer, combine the soap concentrate. Applying the soap in direct sunlight or at temperatures above 90 oF could harm the plants. High humidity and temperatures may make plants more sensitive and stressed. Early in the day or late in the day are the ideal times to treat your plants. Because the soap spray only works while it’s wet, slower drying conditions are preferable for mite or bug control.

It is crucial to spray the underside of the leaves as well as the upper surface because numerous bugs can be found there. Repeat applications may be required every four to seven days (per the label guidelines) until the pests are eradicated due to the relatively brief residual action and the requirement that the insects come into touch with the soap for it to work. Avoid using too much since repeated exposure could cause foliage damage. Always abide by the instructions on the packaging.

When applying insecticidal soaps, you should take the quality of the water into account. The insecticidal soap’s efficiency is diminished by hard water. The ineffectiveness of the soap is brought on by the fatty acids precipitating out of the solution due to the presence of calcium, magnesium, and iron. Utilizing the finest water attainable is crucial. By combining the recommended soap concentration you intend to use with the proper amount of water in a glass jar, you can see if your tap water is compatible. Stir the ingredients and let it to stand for 15 minutes. The water quality is suitable for the spray if the mixture stays consistent and milky. Use distilled or bottled water if there is scum on the surface.

The sole drawbacks of insecticidal soaps are related to their inherent limits.

  • When applied, the soap solution must soak the bug.
  • Because soap dries up or is wiped away, there is no lasting effectiveness.
  • When the soap residue is exposed to high temperatures, phytotoxicity could result.

Wherever gardening materials are offered, insecticidal soaps are available. They are offered in pre-mixed RTU (Ready to Use) spray bottles or as concentrates. Several popular brands of insecticidal soap include:

  • RTU Bonide Insecticide Soap
  • Organic insect soap by Espoma, RTU
  • insecticide soap that is safe for gardens
  • Natural Care Insecticide Soap by Miracle-Gro RTU
  • RTU Natria Insecticide Soap
  • Natural Guard Concentrated Insecticide Soap
  • Concentrated Insect Killing Soap from a Safer Brand
  • RTU of Whitney Farms insecticide soap

Any gardener can benefit greatly from using insecticidal soap. It offers a secure and efficient approach to develop plants naturally, get rid of many soft-bodied pests without using harsh chemicals, and maintain a lush, gorgeous, and healthy garden.

Brands of insecticidal soap may also include spinosad, pyrethrin, neem oil, or sulfur as an extra active component. These organic insecticides can help with pest control.