Organic Pesticide and Fungicide Spray




About: I work at instructables by day, and turn into a stitch witch by night. follow me on instagram @jessyratfink to see what i'm working on! ^_^

This instructable will teach you how to make an all-in-one pesticide and fungicide spray that works great for indoor and outdoor plants. My boyfriend recently got into the IPM (integrated pest management) approach to gardening, so he's been spending a good amount of time learning about natural ways to combat pests and fungus on our plants and I've been learning along with him!

If you're looking to learn about IPM and other foliar sprays you can make, I highly recommend checking out BuildASoil - they have an amazing blog and store and offer fantastic phone support for any problems you run into. My boyfriend's spent a good deal of time on the phone getting advice from them - they're always top notch!

This foliar spray utilizes neem oil, potassium silicate, aloe vera and various essential oils to combat many types of pests and fungi. It can be applied once a week to control any issues that come up with your garden!

The amount of foliar spray this recipe makes should be able to completely saturate at least three large plants - we used it on two three foot tall trees (avocado and lemon) and a few succulents.

Step 1: What You'll Need


  • 1/4 gallon (4 cups) warm water
  • 1/4 tablespoon neem oil
  • 1/2 teaspoon 7.8% potassium silicate solution
  • 1/4 oz (1.5 teaspoons or 150 drops total) assorted essential oils - we're using an even blend of ginger, rosemary, clove, peppermint and eucalyptus
  • 1 tablespoon aloe vera juice (we have a powder we add to water to make this)


All ingredients listed above can be found through BuildASoil and Amazon. BuildASoil offers a complete IPM kit that's great if you're just starting out.

Check out this report from BuildASoil to find out how neem oil, potassium silicate, essential oils and aloe vera work together to create an effective foliar spray. The report also includes links to studies so you can learn more about each ingredient.

Here's a basic summary of why we're using each ingredient:

  • Neem Oil contains a chemical compound called azadirachtin. This compound is toxic to many insects, and acts as a feeding inhibitor and a growth disruptor. It is a natural insecticide that is biodegradable.
  • Aloe vera acts as a source of salicylic acid. Salicylic acid is necessary for activating a plant's immune system to respond to threats.
  • Potassium silicate is a natural fungicide, insecticide and miticide.
  • The essential oils used in the foliar spray have a variety of anti-fungal and pesticide properties. Click through to the report above to learn what other oils you can use.

Step 2: First Mixing

You'll want to take 1-2 cups of warm water (75-85 F) and put it in a large jar.

Add the aloe juice to the warm water and shake to combine. It should be nice an clear once mixed.

Now add in the neem oil and potassium silicate. (You may need to warm the neem oil jar up in some water to make it fluid if it's cold where you are!)

Step 3: Shake to Emulsify

Shake shake and shake some more.

You want to entirely emulsify the mix. It should be nice and creamy looking with no oil floating on top.

If you're having issues with mixing, check out this awesome video by Jeremy from BuildASoil - he's got lots of advice for getting it right:

Step 4: Pour Into the Sprayer + Add the Rest of the Water

Once the mix is emulsified, pour it into the sprayer and add the rest of the warm water. Remember you need four cups total.

Shake again.

Step 5: Add the Essential Oils

Now you'll want to add in your essential oils. You need about 1.5 teaspoons total. We used a little over 1/4 teaspoon per each oil: ginger, rosemary, clove, peppermint and eucalyptus.

Shake super vigorously again to keep things emulsified.

Step 6: Spray!

Pictured above: Limón! He's a lemon tree I grew from seed and Tyler has been keeping him alive and happy for over 2 1/2 years now. Yay for Tyler having a major green thumb!

You will want to only apply this spray out of direct light. Essential oils can cause burns on the leaves if left in direct light. It's also a good idea to wear a mask if you have any respiratory issues!

For inside plants, apply the spray with lights out.

For outside plants, only apply late in the day so there's no direct sunlight beating down on the plants.

Try to apply whenever you'll have at least several hours of darkness. For example, don't apply it to outside plants in the morning - the midday sun could cause burns even thought it was applied hours before.

Completely saturate the leaves (both tops and bottoms!) with the spray until the plant is drooping a bit. Try to keep your focus on the leaves and avoid spraying directly onto the soil.

And there you go! I hope this spray will be useful for you guys - it's been fantastic for us!



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    28 Discussions

    Hari KrishnaD

    Tip 5 months ago

    Instead of Aloe Vera juice, Soap Nut powder/juice ( may be a better option as it is a much better emulsifier and also an insecticide by itself. I am going to experiment with it soon.


    10 months ago

    That a wiki quote apparently it a mild neutrotoxin with a high LD50 for humans and pets.


    10 months ago

    Well it could be dependant on dose and resitance to the Oil may occur over a long period of time (limitation of natural stuff) too. It may harm bees but unlikely.

    nitially found to be active as a feeding inhibitor towards the desert locust (Schistocerca gregaria),[3] it is now known to affect over 200 species of insects, by acting mainly as an antifeedant and growth disruptor. It was recently found that azadirachitin possesses considerable toxicity towards African cotton leafworm (Spodoptera littarolis), which are resistant to a commonly used biological pesticide, Bacillus thuringiensis. Azadirachtin fulfills many of the criteria needed for a good insecticide. Azadirachtin is biodegradable (it degrades within 100 hours when exposed to light and water) and shows very low toxicity to mammals (the LD50 in rats is > 3,540 mg/kg making it practically non-toxic).

    This compound is found in the seeds (0.2 to 0.8 percent by weight) of the neem tree, Azadirachta indica (hence the prefix aza does not imply an aza compound, but refers to the scientific species name). Many more compounds, related to azadirachtin, are present in the seeds as well as in the leaves and the bark of the neem tree which also show strong biological activities among various pest insects [4][5] Effects of these preparations on beneficial arthropods are generally considered to be minimal. Some laboratory and field studies have found neem extracts to be compatible with biological control. Because pure neem oil contains other insecticidal and fungicidal compounds in addition to azadirachtin, it is generally mixed at a rate of 1 ounce per gallon (7.8 ml/l) of water when used as a pesticide.


    4 years ago

    Are any of these ingredients toxic to bees and butterflies? I'm hoping to encourage beneficial insects...

    4 replies

    Thankfully, in the reading I've done, I haven't seen any studies suggest the oils would be toxic to bees or butterflies. Some beekeepers actually use essential oils in their hives to try to combat mite infestations, which is pretty neat.

    I've actually read about certain oils attracting both bees and butterflies, too! I know they like lavender and sage. :)


    The -only- problem I would see with this, is the use of it on any of the Milkweeds (Asclepias tuberosa, and Asclepias syriaca - about 140 species) which are the only plant that the Monarch (Butterfly) Caterpillar can eat. They need these milkweeds to survive. As long as people don't use it on the milkweeds - I see no other problem with it at all!


    Reply 4 years ago on Introduction

    Thats the cool thing about the active ingredient in neem oil, it only effects the bugs that eat the plant tissue making them think they are full so they happily starve! I was thinking we could water it down a bit and use it as diet tea! Back to more serious though this won't effect the beneficials especially if you use it at night as suggested. The bees etc will be sleeping and the mites etc will be about their work. One thing though there are several of the bugs you are targeting that spend their infancy in the top layer of soil so getting it on the soil around the bottom can help with thrips and other hard to get little guys.


    Reply 4 years ago on Introduction

    While Bordeaux is good for fungus and such, it's not real effective on the bad insects.

    Hi, I used an oil-based insecticide on my kale and it killed one of my varietals. Test on a single leaf first to check!


    4 years ago on Introduction

    I like it . Been using a solution made of tobacco and cayenne pepper , works , but leaves an aftertaste that encourages me to go in a new direction ,especially since starting to grow indoors ( No deer in the house) .


    4 years ago on Introduction

    Will this keep my Basil free of leaf fungus which is uncontrollable here in Miami's humid evenings?


    4 years ago on Introduction

    I had success killing lots of pest with alike mixture, no aloe, but capsaicin (Blairs devils drops) and stinging-nettle slurry (stinky). For the slurry you put a lot of stinging nettle in a bucket full of water let it stand for 1 to two weeks.

    2 replies

    Reply 4 years ago on Introduction

    I found a mix with garlic essential oil when I was trying to treat a massive mealy bug infestation at my work. Despite being very dilute my employer hit the roof at the smell. Garlic essential oil is incredibly PUNGENT! It certainly does work but I would not advise using it indoors, except in the greenhouse.

    Garlic is also a very potent antifungal, more effective than thyme, I use it on my horses when they get fungal skin infections (mudfever, greaseheel).

    I have also made a variety of flysprays for the horses with the Garlic essential oil and neem and practically everything but the kitchen sink. Some are more effective, some less, but our flies here are unbelievable and nothing has managed to keep the horses free (or even bearable in some seasons) - even horrible chemicals which I went to as a last resort last summer.


    Reply 4 years ago on Introduction

    Oh nice! I think we're going to try making a pepper/garlic spray soon. Love using hot peppers in stuff like this.

    I think we've got some stinging nettle that we use in plant teas - I'll have to let him know it works for pests too. :)

    The oils here are so heavily diluted you shouldn't have any issues! I did a bit of reading before we started this and didn't find anything out about essential oils and dogs that got me worried. We use it in a yard that two dogs play in with no worries!


    Reply 4 years ago on Introduction

    Well I guess as long as the dogs don't grow leaves etc they're okay. (just teasing, have a giggle)

    Nice work Jessy thanks.