How to Make Garlic Spray to Tackle Pests and Diseases

The mythology behind garlic is long and storied. From vampires to devils to werewolves, garlic is purported to do anything and everything.

While those stories may be myths, the effectiveness of garlic in pest and disease control is not. Garlic is not only a great plant to grow in your garden, but also a great plant to use on your garden.

Garlic bulbs consist of numerous segments called cloves, which can be separated and planted. A biennial usually grown as an annual, garlic boasts many antibiotic and pest-preventive properties as well as many health benefits when consumed.

Does Garlic Spray Work?

Since there are many gardening myths out there, the first question to answer is: does garlic spray actually work? Scientists have wondered the same thing for years. That’s why there are several studies on the topic, with some interesting results.

Researchers have found garlic is a generally effective biopesticide, often achieving similar results to comparable synthetic products. One tested garlic sprays on cotton aphids, another on cabbage flies and houseflies, and another on various pests and diseases like downy mildew.

But what makes it work so well against pests? The answer lies in the sulfur compounds found in garlic cloves. You might recognize sulfur as a powerful standalone fungicide. But when paired with allicin, a compound within garlic, it confuses insects by interfering with their sensory receptors. If you have a case of powdery mildew or downy mildew, garlic spray may also treat it.

In my opinion, the biggest benefit of garlic spray is for the environment. It limits the need to use other, more toxic pesticides in your garden. It can deter beneficial insects too, so it’s important to spray carefully. But it’s generally considered an eco-friendly, green way to treat pest and disease problems.

How to Make Garlic Spray

First, separate your bulbs into cloves — but don’t peel them. Put all of the cloves into a high-quality food processor or blender and add one cup of water. Pulse or chop them well.

After they’re nicely chopped, add in the remaining water. If you were using a food processor, transfer to a blender and blend until the mixture is completely liquefied. It’s important to make sure it’s completely liquid because you’ll be using a spray nozzle to apply. Even small chunks will get caught in the nozzle. Plus, you want to get as much of the garlic to mix with the water as possible.

After a thorough blend, strain through cheesecloth to catch any last chunks that would clog your spray nozzle. Strain a few times if you want to be absolutely sure your final mixture is 100% liquid. Put the mixture into a glass jar for storage.

When you want to use it, mix one part of your concentrated garlic mixture with 10 parts of water and add to a bottle with a spray nozzle top.​

Customizations

All of these have unique characteristics that make them good additions to a garlic pest spray. You can also buy a commercial garlic spray and customize it from there as well.

How to Use Garlic Spray In The Garden

If you need to spray, time it for the early evening. This way, your plants are dry and there is a greater likelihood that the insects you want to get rid of will be out in full force.

Use a standard spray bottle and coat the vegetation of your plants as evenly as you can. Be sure to get the underside of the leaves, as many more annoying bugs like to hide there. I like to use a pressurized pump sprayer to make sure I get even coverage over all of my plants. It makes it a lot easier to deal with a larger garden.

Re-apply your garlic spray at least once a week and after a rain to make sure its pest-repelling properties are put to full use. Only apply on problem areas to limit the impact on beneficial insect populations.

If you are spraying plants that you’re going to eat soon, wash them thoroughly before consuming (unless you like a garlic-flavored garden).