DIY / The Garden

Easy homemade insecticide to protect your garden (without killing the earth)

Homemade Bug Killer

A micro homesteader’s best weapon against garden pests is to make your own homemade insecticide! It’s so frustrating when you go to so much trouble to grow your own food and then BAM these presumptuous beasties show up and start eating all your hard work! I try very hard not to use any store-bought chemicals on my micro homestead.

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This means I am constantly having to come up with ways to battle what Mother Nature throws my way. Are these homemade concoctions as effective as those harsh chemicals? No, not usually, but they DO work, even if they require a bit more work and determination on your part. But as far as I am concerned it is worth it. A huge part of growing my own food (outside of the better taste and variety) is to get away from all the chemicals and pesticides that are present in industrial agriculture that also harm the earth and our bodies.

So if you are just here for the recipe, feel free to scroll on down or use the jump to recipe button. But for those like me who don’t like to do things without understanding WHY (book/plant nerds unite!) I wanted to spend some time going through the components that make up this homemade insecticide. So that we reach an understanding of why it works and contains the elements it does.

Homemade bug killer
My homemade insecticide

Diatomaceous earth

I’m going to say this right off the bat as it is SO important. DO NOT BREATH THIS STUFF IN! Sorry, I didn’t mean to yell, but inhaling this stuff is bad mojo for your lungs. Why? Well, diatomaceous earth is crushed up siliceous (silica-based) sedimentary rock that also contains the fossilized remains of diatoms. This stuff is useful in the garden as it has the power to absorb lipids (fats) which makes it effective against the waxy exoskeleton of many insects. With this removed many insects will fall prey to dehydration.

Neem oil

So what the heck is neem oil and where does it come from? First off let me say that stuff is hella powerful and pretty much death to bugs. Neem oil comes the Azadirachta indica tree, and the active ingredient we want to use in the garden is the Azadirachin. It is used due to its anti-fungal and pesticide properties. It works great against such pests as aphids, thrips (I seriously hate these guys), whiteflies and a host of other insects.

Dish soap

We need the dish soap in order to act as a surfactant for the neem oil. Wait a what? A surfactant is something that helps to lower the surface tension between two liquids. Neem being an oil would otherwise just sit on the surface of the water and we don’t want that. The dish soap helps the neem oil to mix into the solution so that it can be diluted.


The water is essentially the DD (Designated driver), it’s just here to get everything else to where it’s going, safety (ie: diluted). That’s pretty much it, in terms of why the water is there…short and sweet.

I though diatomaceous earth doesn’t work when it’s wet?

You are correct, it doesn’t! But it will start to work once it is dry! I tried applying the diatomaceous earth by itself and I found it just covered the leaves in clumps. When it is diluted in water it coats the leaves better. Plus I really view it as a two for one deal. You get the benefits of the diatomaceous earth PLUS the benefits of neem oil. The neem oil starts working on contact and then tag teams over to the diatomaceous earth once dry. Plus they each work on different types of bugs and I haven’t found any negatives that to stop me from mixing them.

When to apply homemade insecticide

As this homemade bug killer contains neem oil we need to make sure to apply it when the sun isn’t shining. Bright sun could cause the leaves to burn because of the neem oil. So it is best to apply it towards the evening. When you first start using it you should also to a test area to make sure it doesn’t harm your plant. Also, as we have mixed in diatomaceous earth you will want to make sure that rain isn’t coming in the next few days or it will just wash off.

Recently, I went out into the garden to take a picture of a wee baby gooseberry I had seen the day before. Because I mean who doesn’t take pictures of adorable tiny fruits and plant babies? It seriously can’t just be me. But anyway, I went to take a picture to send to my mum and GASP…my gooseberry plant was under attack! I’m talking complete branches stripped bare that were fine the day before. This is why you have to be vigilant in the garden! If I had waited a day or two more the entire plant could have been stripped!

How to deal with gooseberry sawfly
Offending caterpillars devouring my gooseberry bush

Upon further investigation I discovered the green caterpillars that were the cause of all the destruction. I think they were gooseberry sawfly but I am no entomologist. So I ran back into the house, headed for my crappy little kitchen and brewed up a batch of my homemade bug killer and holy cow did it work against these guys! Within 5 minutes of me spraying the bush, the ground was littered with caterpillar casualties. I have since been checking on my gooseberries daily and there have been no repeat attacks!

homemade insecticide
Dead caterpillars after being sprayed with my homemade insecticide

The wee gooseberry I originally went out to take a picture of is getting bigger by the day and I’m sure it appreciates my efforts!

Homemade insecticide

This is powerful stuff and I use it on my micro homestead to deal with a variety of insects and other pests.
Prep Time5 minutes
Active Time5 minutes
Total Time5 minutes
Keyword: diatomaceous earth, homemade bug killer, homemade insecticide, natural bug killer, natural insectide, neem oil
Yield: 2 Cups


  • 8 oz Spray bottle (prefereably amber glass)
  • Funnel or rolled up paper to act as a funnel
  • Measuring cup
  • Measuring spoons


  • 1 Tbsp Diatomaceous earth (be careful not to breath it in)
  • 15 Drops Neem oil
  • ¼ Tsp Dish soap
  • 2 Cups Water


  • Add the dish soap and neem oil to the glass bottle.
  • Using a funnel (or make your own with a piece of paper) carefully put the diatomaceous earth into the glass bottle. Be carefull not to introduce a lot of it into the air as you don't want to breath it in.
  • Top off the glass bottle with 2 cups of water.


As there is neem oil in the recipe it is best to do a patch test on your plant before spraying the whole thing. Just to make sure your plant is not damaged by it. Also, make sure to spray only when there is indirect light. Spraying neem oil on a plant in direct sunlight can lead to burning.

So there you have it, my gooseberry sawfly epic and the homemade insecticide that saved the day!

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