How to Use Insecticidal Soap on Plants

By: Julie Day

Bottle of Ortho insecticidal soap for plants
Problems with spider mites? Give your plants a bath with insecticidal soap! Made from a simple soap solution, insecticidal soap is a greener, more eco-friendly approach to insect problems in the garden and on houseplants. You can buy insecticidal soap in a ready-to-use spray or make your own using this simple recipe.

Insects Affected by Insecticidal Soap

Insecticidal soaps work by disrupting the cell membranes and dissolving the natural waxy coatings found on soft-bodied insects including:

  • Aphids
  • Immature leafhoppers
  • Mealy bugs
  • Scales
  • Spider mites
  • Thrips
  • Immature white flies
  • Eggs and pupae of other insects

Eco-Friendly Advantages of Insecticidal Soap

If made and used correctly, insecticidal soap is more eco-friendly than traditional insecticides since it:

  • Has no residual effect.
  • Only works when coming in direct contact with soft-bodied insects.
  • Is biodegradable and nontoxic (if the right soap is used).
  • Kills target insects without harming birds or hard-bodied beneficial insects such as predatory wasps, lacewings, and pollinating bees.

Spraying houseplant with insecticidal soap

How to Apply Insecticidal Soap to Plants

Follow these tips when applying insecticidal soap to plants:

  • Avoid Sensitive Plants: Some plants are known to be sensitive to insecticidal soap sprays. In particular, be careful around ferns, succulents, ivy, palms, lantana, azaleas, some tomatoes, and plants with waxy leaves. Also, avoid spraying tender new growth or blooming plants with insecticidal soap.
  • Shake Well: Shake the insecticidal soap solution well just before spraying to disperse the soap throughout the water.
  • Test First: If this is your first time using insecticidal soap, conduct a test spray on an inconspicuous branch to make sure your plant can tolerate it. Wait 24 hours and look for burned or scorched spots on the leaves before proceeding. If the insecticidal soap damages the plant, dilute it the in half and try again. If it still burns, you probably need to avoid spraying that plant.
  • Label giving ingredients on insecticidal soap spray bottle

    Ingredients in insecticidal soap

  • Stressed Plants: Before treating with insecticidal soap, make sure your plants have been watered and aren’t under stress. Never spray wilted plants.
  • When to Spray: The best time to spray with insecticidal soap is in the early morning or evening when temperatures are cool and plants are shaded, since the spray will stay wet longer and be more effective.
  • Apply Thoroughly: Many soft-bodied insects hang out on the undersides of leaves. Be sure to spray both the tops and bottoms of leaves with insecticidal soap, as well as the stems. Remember that insecticidal soap will only work on the bugs that actually get wet. Since the soap is harmless once it dries, any unsprayed bugs will survive the treatment.
  • Repeat Treatment: Insect infestations often require a second treatment with insecticidal soap in a week or so, and possibly even a third. For severe problems, you may want to apply several days in a row, then follow up a week or two later. Keep in mind that the spray stops working once it dries and completely washes away in rain.

Further Information

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16 Comments on “How to Use Insecticidal Soap on Plants”

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  • haftu Says:
    July 29th, 2016 at 8:38 am

    I need to know about cactus disease. Can u tell me?



  • tina lopez Says:
    May 24th, 2016 at 12:40 pm

    I am trying to grow squash and all I am getting are male blossoms , how can I try to get them to produce female blossoms?



  • PMH Says:
    January 19th, 2016 at 11:48 am

    Apparently, you’ve stopped replying to questions.

    But maybe this is important enough (for everybody else to know):

    For indoor plants, isn’t it important to rinse off the soap?

    Before it dries?

    And – more importantly – keep it out of the soil! (No?)

    I sprayed some Camellias.

    I tried to keep the (Ivory liquid hand soap, diluted properly) out of the dirt, but it was hard to know how well I succeded.

    I did them outside, except for the one that’s too big to lift.

    I forget whether I rinsed them off.

    Many of them had severe problems afterwards, dropping almost all their leaves. The leaves didn’t show any of the usual Camellia problem signs; they had what looks like almost burns – probably where the soap would have run down to and dried. That’s pretty suspicious!

    The big one may or may not survive. 🙁



  • Tammie Jo Says:
    September 13th, 2015 at 10:26 pm

    I’ve noticed what looks like little tripes boring into the side of the new buds on my portulaca plant. You can pull them out but I can’t really tell what they are. Every bud that has this on/in it fails to open. Do you know what they are? Thanks



  • mary lou sugg Says:
    September 9th, 2015 at 12:06 pm

    Have had all summer what looks like dandruf all over 3 large hibuscus. They fly and are millions of them. Used every thing i have been told and nothing helped. They do not hurt the plant. The plants were very healthy and beautiful but these things were highly irritating. Pulled them all up and burned them. Now they are on everything else and all my neighbors plants. Could they be white flies?



  • Bobbi Says:
    September 8th, 2015 at 12:11 pm

    Can you use insectidal soap on a potted tropical Hibuscus?



  • Kat Savage Says:
    August 9th, 2015 at 12:51 pm

    I have had aphids all summer long and can’t get rid of them. they are eating all my zinnias, I pulled them out last night, my runner beans, tomatoes, moon flwrs, cukes and almost every other plant in my garden. I’ve sprayed with about 3 different things off the shelf (with help of course) including malathion, Bayer Insect and pest control, which boasted of a guarantee “no more pests on contact”, yet I still have APHIDS eating my moon flw vines. Just crawling up the vines and soon I will have NO flowers again! what can I do at this stage of the year now?
    I am so frustrated, I just want to tear my garden down, the whole thing! but all my hard work is stopping me. soon it’ll be too late as the season will end and I won’t have a choice. 🙁
    any help will be appreciated and I have read most of your advice, just am skeptical at this point.
    thanks in advance,
    kat



  • Jude Phillips Says:
    July 27th, 2015 at 11:18 am

    Some type of small red bugs invested & ate most of my lily s and I have scooped them up in the soil also. What are they and what to do about destroying them. In all the years of growing these plants this is the first time I have ever experienced this invasion.



  • Samantha K Says:
    May 30th, 2015 at 3:23 pm

    “… since the spray will stay wet longer and be more effective.”

    Other sources I’ve read say the soap works only if sprayed on the insect, that it doesn’t work if they walk through or eat it. If that’s true, why would it matter how long the spray stays wet?



  • PJT Says:
    October 29th, 2014 at 12:55 pm

    Can u use insecticidal soap in an atomizer?



  • Doreen Ong Says:
    August 3rd, 2014 at 9:02 pm

    Can I get rid of millipedes in the soil using your insecticidal soap?



  • John Vorel Says:
    July 22nd, 2014 at 4:36 pm

    update-on-the-ortho-elementals-entry-from-my-old-blog



  • John Vorel Says:
    July 22nd, 2014 at 4:24 pm

    From what I can tell from the internet Ortho is not willing to give more description of what is in this stuff on the internet….they try to present this as an organic alternative but it is not. Why is it so hard to find information about applying it? I used it on an infestation on Bok Choi plants but now I feel as though my plants should not be eaten… will chuck them away! Mad as heck!!


  • Official Comment:


    Ben Erickson Says:
    May 19th, 2014 at 4:30 pm

    Denyce,
    If you’re using a store bought insecticidal soap on your plants, follow the instructions that came with it on how often to use it. If you’re making your own insecticidal soap, see the “Repeat Treatment” section at the bottom of the article above. Thank you for your interest!



  • Denyce Brown Says:
    May 19th, 2014 at 4:11 pm

    Hello I just read the information about your product. This is my question how often do I use this product on my roses. last year I had to dig up every rose I had root and all because they ended up with the rosette virus. just the other day and this morning I have noticed three roses are back. I sprayed them with your product this morning. how often do I spray them because I do not want them to get infected again like the others



  • Fariba Says:
    May 14th, 2013 at 2:13 am

    Thanks for your well-written, practical set of remedies. I have noticed very tiny brown insects that come out of the soil. What are they? Are they dangerous for the plant? I have an irresistible desire to destroy any villain moving on my plants. No photo of them was amongst the common plant pests.


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