Homemade Organic Garden Soap Spray Recipe: Kill Aphids & Other Pest Insects
Are aphids, mealybugs, or other pesky little insects making themselves at home in your garden? Donβt let them get too comfortable! Try using this mild, inexpensive, organic homemade soap spray to stop them in their tracks, and prevent them from further damaging your plants. Insecticidal soap spray can also be used indoors on houseplants. Read along to learn how easy it is to make your own!
When mixed and used correctly, an application of insecticidal soap is very effective at killing small soft-bodied pest insects like aphids, mealybugs, spider mites, white flies, psyllids, and scale. On the other hand, it is also gentle on your plants, non-toxic to wildlife, and does not harm beneficial insects like ladybugs, lacewings or bees!
Keep in mind that seeing a couple of bugs here and there is totally normal and even expected in an organic garden. When there are just a handful of aphids or other pests around, we generally do not intervene. Instead, we hope that that their natural predators like ladybugs or lacewings will help keep their population in check. We also buy and release ladybugs to help with that! But when it is apparent the βbad guysβ are significantly outnumbering the good? Soap spray to the rescue!
Disclosure: This post contains some affiliate links to products for your convenience, such as to items on Amazon. I gain a small commission from purchases made through those links, at no additional cost to you.
What Is Insecticidal Soap, & How Does It Work?
Insecticidal soap, also known as horticultural soap, works to kill soft-bodied insects by disrupting their sensitive cell membrane. Essentially, it coats and penetrates the natural protective barrier around their body, which causes them to desiccate β or dry out. It kills them by pest-specific physical means, and is not “poisoning” them. Thus, soap sprays are NOT effective against insects that have a hard exoskeleton or different anatomy – such as most beetles, crickets, bees, grasshoppers, pill bugs, grubs, or even caterpillars.
Furthermore, insect soap spray has little-to-no residual effect, and only kills on direct contact. This means that it must be sprayed right on to the target pests to work.
There are many commercially pre-made insecticidal soaps available to buy. However, while those are typically rated for βorganic gardeningβ and are more environmentally-friendly than most other pesticides, they often still include a long list of chemical ingredients. Therefore, I feel much more comfortable making our own! I mean, why not? Homemade insecticidal soap is extremely cheap and easy to make, and is just about as natural and gentle as you can get.
INSECT SOAP SPRAY RECIPE
To create your own homemade insect soap spray, you only need two ingredients: liquid soap and water. Pure castile soap is the best choice for making soap spray. It is effective and wonβt harm your plants. We use Dr. Bronnerβs liquid castile soap. Peppermint Dr. Bronnerβs soap provides a further line of defense, since peppermint deters pests! Avoid using soaps or detergents with bleach or degreaser additives, or those intended for the dishwashing machine.
Mixing Instructions:
- Simply combine 1 tablespoon of liquid soap per quart of water. Mix only what you will use that day.
- For a larger batch, use 5 to 6 tablespoons of soap per gallon of water.
- Shake together in your sprayer to thoroughly mix. Use warm water to promote mixing.
- For light applications, mix them in a small classic spray bottle. To treat a larger plant or area, we use a half-gallon pump sprayer – to create more soap spray, and also reduce the need to repeatedly squeeze a βtriggerβ during application. If you re-use old cleaning spray bottles, make sure to thoroughly wash them out before using them in your garden!
Application Instructions:
- As with any plant treatment or spray, it is “best practice” to apply it to a small test area a day or two before treating a larger area. Honestly, we’ve never had issues with soap spray – but I have to give you the disclaimer!
- It is best to apply soap spray in the evening. Do not apply spray in direct sunlight, as it can sunburn plant leaves – known as phototoxicity. Additionally, beneficial insects are less active during evening hours!
- Insect soap spray only kills on direct contact, so spray it right on the pests! Coat them thoroughly.
- Turn over or peel open curled-up leaves as needed to access hard-to-reach bugs. I usually get all up in there and rub the infected areas and leaves as I spray, manually squishing the aphids or mealybugs with my fingers at the same time.
- If it is forecasted to be very hot and sunny the day after your evening application, I suggest rinsing off the residual soap (and now – dead bugs) by spraying the plant with water by the next morning. Again, this is mostly to prevent potential sunburn, though I like the satisfaction of cleaning up and spraying away the victims too! Avoid wetting leaves during direct sunlight hours.
- Re-apply soap spray every 4 to 7 days as needed. It may take several treatments to solve the pest problem.
- Treat early. It is much easier to nip a little infestation in the bud than wait and battle an epic one!
Still have pests on your plants?
For persistent problems, insecticidal soap spray treatments can be used in conjunction with neem oil for further pest prevention. Neem oil repels most small pest insects, and also prevents fungal diseases like powdery mildew. It is very popular in organic gardening, but also frequently used incorrectly. Therefore, read this article to learn how to properly mix and use neem oil!
If you’re frustrated and struggling with pests, try not to stress! It is a normal part of organic gardening. Your garden shouldn’t be devoid of all life, nor your plants completely pest-free! That simply isn’t natural. Yet with some good tips and tools under your belt, you should be able to keep them to a manageable level.
For more tips on organic pest control, be sure to check out our other related articles:
- Organic Pest Control, Part 1: How to Prevent Pests in the Garden
- How to Identify the Top 18 Garden Pests, and Beneficial Insects
- Over 25 Ways to Stop Pests From Destroying Your Garden
- Organic Cannabis Pest Control: How to Keep the Bugs Off Your Nugs
And it’s as simple as that!
I told you that making your own organic soap spray is easy! Now you can safely battle the pests in your garden in an effective, non-toxic and environmentally-friendly way.
In all, I hope you found this article helpful and interesting! Please feel free to ask questions, or spread the love by sharing this post. May your plants be happy, healthy, and mostly pest-free!
21 Comments
Silvia Fernandez
So I didn’t read the whole posting before applying this insectiside. Should I rinse the plant and apply it tonight? I have a question in regards to leftover liquid. Do I throw it away or how long can it be kept?
Aaron (Mr. DeannaCat)
Hello Silvia, we usually store whatever leftover soap mixture we have in the sprayer and save it for later use. It is best to apply the soap spray at night but we have also used it during the day with little to no negative effect on the plant. However, we will rinse it the day or two after, especially if the treated plants were leafy green vegetables that we intend to eat. Hope that helps and good luck!
Christine Belker
I just subscribed to Homestead & Chill. I’ll have to say it is the most informative website I’ve ever visited. You are so very thorough about everything! What a wealth of information!
Thanks,
Christine B
Aaron (Mr. DeannaCat)
Thank you so much for the kind words and the support!
Beverly
Planted my first monarch/pollinator garden last spring. Joy of the garden & incredible monarchs really kept me sane during Covid year. But aphids!!! Milkweed looked like it had orange stems. I tried spraying with water and squishing (cried when I squished a wee monarch caterpillar). Horrid, endless battle! Loved this article. Will use Castile soap as you directed. Been growing roses for many years. Do you have any specific advice for environmentally friendly maintenance of roses?
Aaron (Mr. DeannaCat)
Hello Beverly, glad to hear you have made monarchs a priority and that they helped you just as much as you helped them! Aphids do love milkweed so using soap spray and blasts of water works best. We haven’t actually grown roses at all so we don’t have much to offer as far as they are concerned. I would try using the soap spray or using a neem oil foliar spray for pest prevention, although I wouldn’t spray the neem foliar on your roses once the flowers have emerged unless absolutely necessary. Hope that helps and good luck! Keep us up to date on your progress.
Rose
Hello, i have a question do you rinse off the Soap the nextday or just leave it as it is. Thank you
DeannaCat
Hi Rose, I usually like to rinse if off. You don’t absolutely have to, but that is what we prefer to do. Thanks for reading!
Aly Cardenas
Hi!!
Love your blog so much, thanks for all that you share! I have a question regarding clovers! Theyβre invading my raised bed and I swear every time I pull 5, 10 more pop up to replace it! Can they coexist with my garden or do I need to intervene and spray or what do you recommend??
Aaron (Mr. DeannaCat)
Hi Aly, clover is one that is really hard to get rid of but it seems to only pop up during certain times of the year and is quite easy to pull up by the roots as needed. I would not recommend spraying anything on them, just keep up with your weeding and if you pull them before they go to seed, there will be less in numbers as time goes by.
Dave
I am planning to use Castile soap to treat insects in my vegetable garden. I purchased a 10 oz bottle of Dr. Jacobs Pure Castile Peppermint foaming hand soap. Is this the correct soap to safely use in my garden, and if so, do you have any recommendations on how to mix it properly?
DeannaCat
Hi Dave, that soap sound similar to the castile soap we use… except for the “foaming” part. Is it just the pump that makes it foam? If so, unscrew the top and then use it as directed in this article. But it there are a bunch of other ingredients in it (aside from pure castile soap) then it is not the same of what we use or recommend.
Dave
Thanks for the quick reply. I checked the bottle of Dr. Jacobs Pure Castile Peppermint foaming hand soap, and ingredients include water, coconut oil, sunflower seed oil, potassium hydroxide , glycerin, peppermint oil, citric acid, and vitamin E. Are they the same ingredients as the Dr. Bronner’s you recommend for use? If not, do you think I would be safe to use this type on my garden plants?
Diane
I have a bottle of Dr. Jacobs Pure Castile peppermint soap and no do not use, you will kill your garden & fruit trees. Its not the same as Dr. Bronner’s peppermint soap that we have used.
Susan
Love your blog, tons of information.
When I tackle the aphids I fill a plastic food storage container (8β diameter) with the soapy water, I bend down the tip of the plant stem thatβs loaded with the aphids and let them soak for 10 seconds. I do all effected areas on the plant then I go back using clean water and Swish the stems around in the water and ALL those nasty aphids come floating off.
Andreea
Hello, can I use this solution on plants with edible roots? Will the soap remain in the soil and then be absorbed by the root?
DeannaCat
Hi Andreea. Hmmm… I haven’t really thought about that before. What kind of roots? I think if you applied the soap lightly and weren’t planning to harvest the roots in the immediate future (meaning, they’d get plenty of water/washing away the soap for the next month or so) I can’t imagine it leaving a residue or being absorbed.
Keiko
Hi! Could I spray this directly on the roots when repotting? I found some pests and I decided to completely repot my plants and before I repot, maybe spray on the roots with some soil that wont come off the roots? Thank you.
Aaron (Mr. DeannaCat)
Hello Keiko, you could try and spray the roots with the soap spray since it is fairly benign and it shouldn’t have too much of a negative effect on your plants although we have yet to try this and usually focus the spray on the parts of the plants we can see. Good luck!
Jennie
Hi there! Thank you for the info! Will this also work on the pesky little white fluffy pests I get on my succulents?
DeannaCat
Hi there! Yes, those are most likely mealybugs! You can definitely use soap spray for those. Another option, if there aren’t too many of them, is to dip a Q-tip in rubbing alcohol and swap each of them with it. It kills them in the same manner. Good luck!