I am finally sharing this post with you on how to make an easy homemade fungicide spray for plants with just two ingredients.
SPRING is finally here! I have been waiting for months to finally share a gardening post with you, it has been so long!
This is something I have mentioned before, but haven’t done a full post on.
The best part? This is great for MORE than just preventing fungus and bacteria, be sure to read the chemist notes below to learn more.
Pin this post to save for later: Easy Homemade Fungicide Spray for Plants – Two Ingredients!!
Homemade Weed Killer Recipe Can Be Found here!
Ingredients For Homemade Fungicide:
- 1 aspirin tablet 325 mg
- 1 gallon water
- Spray bottle (read this post for spray bottle info)
- A few drops of dish soap (OPTIONAL)
Directions:
- Crush aspirin up until it is a fine powder.
- Mix with one gallon of water.
- Add contents to a spray bottle. At this point, you can add a few drops of soap if you choose too. PLEASE read notes below about the dish soap!!
- Using the mist setting, spray leaves of plant until lightly, but evenly coated.
- Use every few weeks during the growing season.
For More Aggressive Treatments:
I wanted to include a quick alternative solution for this. I have done quite a bit of research on using aspirin for plants. In a few horticulture books, the solution mentioned was 1 aspirin to 1 LITER of water. This makes it a little more concentrated, so if you want to really make sure your plant is protected from disease, you can use this ratio. I have used the 1 liter of water for my roses, and they responded well.
Information on Optional Dish Soap:
Dish soap plays one roll in this. It makes the solution stick to the leaves. I usually don’t use it, and it works fine. If you really want to make sure the solution sticks to the leaves for longer, it doesn’t hurt to add a few drops of dish soap.
I wouldn’t use dish soap on any thin leaves or sensitive leaves. Read more below under the chemistry of this solution. You can also try our DIY insecticidal soap.
The Chemistry Behind This Easy Homemade Fungicide Spray for Plants
There is a good reason this solution works, and it’s all based on Chemistry!
Aspirin is known in the chemistry world as acetylsalicylic acid. It was invented by a chemist, then many decades later, a scientist by the name of Bayer studied the use of acetylsalicylic acid for medicinal uses. He called it aspirin and started selling it.
To get a deep history and unique article, read this post from last year.
For this article, let’s discuss why aspirin works for this solution:
Aspirin is white, crystalline powder with weak acidic properties. When mixed with water, it turns back into salicylic acid and acetic acid (vinegar). The compound salicylic acid is the key to its uniqueness.
Salicylic Acid
The salicylic acid works as an antifungal for plants when the leaves are sprayed. In this study, it was highly effective at preventing wilt disease in green peppers!
It works to prevent many types of fungus in plants like wilt, rust, and powdery mildew.
Optional Dish Soap
The reason this is optional is because it isn’t necessary, BUT it does help solution stick better. This is good for treating something more aggressively, or if you live in a place with a lot rain. I don’t typically add any dish soap, and the solution works fine.
You can use insecticidal soap or dishwashing liquid like Dawn.
How it Can Help Grow Healthier Blooms
Believe it or not, this does wonders for blooms! Like I mention in this post, salicin was originally extracted from willow bark. Salicin was the precursor to aspirin. Willow is an incredible rooting hormone!
Spraying the leaves of your plants with this spray enhances blooms, makes them darker, and more vivid.
It can also make your plant grow larger with regular use!
What Type of Plants Can I Use This On?
Really any! I use this on all my flowers in pots and in the ground. The research article I shared above talked about using it on peppers, so it can also be helpful in a vegetable garden. Remember to start with one gallon of water to one aspirin, then if you decide to increase the concentration to one liter of water, feel free to do so!
Aspirin is a popular tool among gardeners. I came across many people who used it for their plants when I took horticulture.
Precautions:
DON’T spray this on your plants when temperatures are above 90 degrees! As with any fungicide, really hot temperatures can cause scorching!!
DON’T spray more than every two weeks!
DON’T combine this with other fungicide sprays especially heavy duty ones!
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Alexis is an investigative chemist sharing her expertise in cleaning, skincare, gardening, and home hacks. She personally tests out products like the best skincare products or home products then shares not only the science behind how it works, but also her personal results. She is the mom of two living in Texas with her husband. Find her on Instagram for fantastic videos, tips, and behind the scenes.
So I should spray all of my plants regardless of any visible problems. Is it helping to grow a healthier plant? (vegetables included) Thanks Alexis, I look forward to all of your helpful posts.
You can use it as a preventive spray if you would like. It does help plants grow healthier and is good for vegetable plants!
Use comprehensive ground up in soil and hole it actually takes care of every I use it all the time borage also it also is good to plant it by them its a pollinate magnet
What about seedlings? I’m thinking as a prevention method.
Some of the research I’ve read says you can use it on seedlings. I haven’t tried it for that though.
Sounds interesting
It’s a neat little tip!
I used to spray dish doap mixed w water on my yard once a month. It worked wonders! Keeping dust off plants allows them to absorb sunlight better and expel gases. Every 3 monthhs i added a tablespoon of mouthwash to that mix, in a hose sprayer. My grass and roses loved it. The aspirin makes sense to use. Am going to try it out. Thanks.
Hope you enjoy using it!! It is really a great and easy option!
Hi Alexis… (late to comment) love this, and I have the ingredients on hand! Will this work for the “rust” on my roses? Between that and black spot fungus, these “diseases” plague my roses the most. Can I use this solution on my geranium plant, the one that has spots on the leaves? Do I spray the whole leaf, or just the underside?
This should work on rust! I haven’t had rust on my roses, but it does work for powdery mildew and other fungus issues on roses. You can use on geraniums too! Lightly spray the entire leaf
Hello, Thank you for your article! We have 2 young Honey Crisp Apple Trees that seem to have a Cedar Apple Rust problem. We live in a forested neighborhood so cannot remove surrounding trees. Do you think this homemade fungicide could benefit them?
Hi Deb! I have never used this on fruit trees, but gardeners say it is good for all fruits and vegetables. I have used it on vegetable plants and it works great. I would test a little portion of your tree to see how it benefits!
Alexis, thanks for all of your gardening help! Love that you explain so well the why as well in what you discuss!!! Could I use this spray on my Basil plant. Will it be safe for my harvesting? Thanks
Yes you can! I know many who use it on their herbs or vegetable plants 🙂
Can I use this fungicides on my yucca
Plant?
It works great for most plants, but I have never used it on a Yucca. I would test a small area
Will the spray deter beetles and other bugs.
I’m not sure about beetles, but it does deter flying insects.
Alexis, first I want to thank for posting the herbacide recipe. We have had an unusually rainy summer here in Minnesota and the crab grass and Creeping Charlie have been biblical. My neighbors on either side of me have Silver Maple trees so I have little Silver Maple volunteers everywhere. Once they get rooted they are hard to get rid of. The herbacide really helps.
My grape vine has had a fungus problem this year so I will definately will be trying the aspirin remedy.
Thank you for all you do.
Hi Sheila! I hope you enjoy using this fungicide, it has been so helpful for my plants over the years. Thank you!!
Will this work on a sago palm and hibiscus plants? I live in the tropics, Puerto Vallarta. Thanks.
I’ve used it on hibiscus, but I am not sure about the other. I would recommend testing a small area of the plant to be sure it reacts okay. For the most part, it is safe for all plants
So, it is getting close to 90+ during the day. Can I spray it in the evening? Or, will the leaves still burn the next day?
I continue to use it when temperatures are below 90, but high 80s. Just test a small leaf area in the evening, keep an eye out for several days. If it looks fine, then it is safe to use while temps are still in the high 80s 🙂
Hi – I have some beautiful elephant ears but they have developed some sort of fungus or rust problem.. I read where a copper type fungicide would work to get rid of it – It did not work.. I have cut so many of my leaves off of them I am afraid it will hurt the tubers for next year.. I am going to try this aspirin treatment – however, if you have any other ideas I would be glad to hear it… Thank you so much.
You can try this on elephant ears! My mom has used this on hers before and it worked. It is worth a try 🙂
Hi Alexis,
I’m wondering if it’s possible to add boric acid and/or Epsom salts to paint to make them more fire retardant? I’ve seen that they can help make natural fabric more fire retardant. To purchase paint that has fire retardant in it is pretty expensive. Any thoughts? I live in Northern CA and of course, fire season is pretty much here already, so I’m trying to make my home as safe as possible.
Thanks!
Val
I have read studies of using boric acid to make certain things more fire resistant, but I have not read any successful studies for paint.I think a lot of that would depend on the type of paint, environment, and the amount of substance you are using to make it actually work. Sorry I don’t have anything more specific for you!
adding asprin when you plant tomato is that ok? and do you have a good spider killer ?ty grace
We have had readers use this on things like tomatoes with success, but I have not used it personally. It should be safe though. I have a DIY roach spray and some tips for roaches that also work for spiders!
Sorry I meant comfrey not comprehensive