I don’t think I’ve lived a single day without having garlic in my house. I put it in almost every savory dish I make, and it’s also surprisingly medicinal. This makes it invaluable for any household. But did you know that you can also use garlic to control pests in the garden?
It’s true! Garlic is a surprisingly effective pesticide and fungicide and has multiple uses on the farm. There are even scientific studies to back up what many gardeners have known for centuries.
Read on to find out how you can put garlic (Allium sativum) to use for your own garden needs.
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What pests can be controlled with garlic?
Garlic’s sulfur compounds are what make it so hot when you bite into it. Few people can snack on raw garlic without wincing, and it has a similar effect on other mammals and insects.
The active compounds found in garlic include diallyl disulfide, dimethyl trisulfide, and diallyl tetrasulfide. These compounds are repellent to many insect pests, but are also toxic, even fatal, to others.
Some of the species of animals and insects that garlic can repel include:
- aphids
- Ants
- Legionnaires
- Beetles (including flea beetles)
- Cabbage maggots (adults and eggs, not larvae)
- The caterpillars
- cutworm
- Stag
- fruit flies
- Midges (adults and eggs, not larvae)
- marmots/groundhogs
- Larvae
- Mouse
- Moles
- moths
- Rabbits: watch out! Garlic can kill pet rabbits if ingested
- root borers
- slugs
- Snails
- Mites
- Thorny Soldier Bugs: Potentially Deadly Reaction
- squirrels
- Termites
- vine borers
- weevils
- whiteflies
- Yellow mealworms (and their larvae): life-threatening reaction
Methods for repelling these species may differ, but we’ll get to that a bit later in this article.
What about pathogens?
Absolutely yes. Garlic’s natural fungicidal properties are what make it so effective in treating conditions such as athlete’s foot and candida in humans. As such, it can also be used to treat outdoor fungal pathogens, especially those that like to sit in the ground and wait for potential victims.
In addition to treating the soil for damping off, I have used garlic infused water to treat powdery mildew, mildew and rust on various species.
Is garlic potentially harmful to plants or pets?
The short answer here is “no”, but there are some aspects you need to keep in mind.
Since garlic is organic and you dilute the juice a bit, it’s unlikely to harm your plants when used as a pesticide or fungicide.
The main problems that can arise would be if you spray your plants at the hottest time of the day. Water droplets on leaves and stems can act as mini magnifying glasses for the sun. As a result, your plants can suffer nasty burns.
If you are treating your plants for insect pests or fungal problems, spray them early in the morning before the sun reaches its zenith. This way the excess moisture has time to evaporate before it has a chance to burn.
As for pets, almost all animals avoid garlic as much as possible. They usually can’t stand the smell of it, but the spray won’t hurt them. Fortunately, most also avoid ingesting it.
The only type of pet susceptible to garlic is the pet rabbit. Alliums such as garlic and onions can be immunosuppressive for rabbits which can cause an anaphylactic reaction. Luckily, they usually can’t stand the smell and tend to stay away from it as much as possible.
When it comes to plant health, keep in mind that just as garlic has good neighbors, it also has bad ones. If you plan to use garlic for pest control, be sure not to grow it with incompatible species.
For example, garlic can stunt the growth of carrots, peas, beans, parsley and asparagus. Additionally, it does not like to be planted near other alliums, including onions, shallots, chives, and scallions. This is because the alliums compete for nutrients and do not play well together at all.
What type of garlic to use
The best garlic cultivars to use are those that are the most potent. By this we mean those which have the strongest and fieriest flavor; the kind that makes your mouth burn and your eyes water if you taste it. Since you’re using garlic for pest control, diffusing its oils and scent to an area, you’ll want to aim for a potent potency.
Bogatyr garlic is colloquially known as “Russian penicillin” because its powerful compounds are excellent for fighting all kinds of health problems. Behind this are Siberian and red Donetsk (Ukrainian) varieties. Basically, if he hails from Eastern Europe, you’ll know that his powerful Slavic genes will knock down any pests you’re fighting.
Methods of using garlic for pest control
You can use garlic for pest control in different ways. These will depend on the types of pests or pathogens you are dealing with. Plus, you can often combine techniques to double your pest control.
Think of it as treating an infected wound with an oral/internal medication and a topical poultice. If you treat a problem with two complementary approaches, they often meet in the middle for ideal effect.
Companion/intercropping
Many people plant garlic in and around their crops as beneficial companion plants.
For example, garlic can be exceptionally useful when planted around fruit trees on the drip border. Herbivores such as deer hate its scent and will avoid stepping on it or crossing it to get to the tasty tree. The same goes for squirrels who would otherwise try to reach your crop before you.
Garlic is also an excellent companion plant for tomatoes, eggplant, peppers, cabbage, kale, broccoli, cauliflower, Brussels sprouts, kohlrabi and beets. It can help repel cabbage white moths, nightshade hornworms, aphids and various other pests of these plants.
Foliar spray
To do a foliar spray, you can prepare a good amount of garlic water and water the affected plants with it.
If you have a juicer, take a few bulbs of garlic and peel the cloves. Then put them in the juicer with a few spoonfuls of water until you have 1/2 cup of concentrated garlic juice.
If not, you can either crush them with a mortar and pestle or run them through a blender with a bit more water.
Mix 1 tablespoon of concentrated garlic juice with 3 cups of water and decant it into a spray bottle. Then water the affected plants as needed. I find cackling and swearing at the bugs I’m spraying is immensely cathartic and can even improve the effectiveness of the spray.
Topical soil treatment
Cutworms have been the bane of my existence as a gardener here in the Laurentians. They cut my corn and pigweed multiple times and generally wreaked havoc on anything I tried to plant.
I’ve used pest garlic to deal with those jolts to good effect when I haven’t had the time or patience to wrap individual stems with cardboard to save them.
Mince or crush a handful of fresh garlic cloves, then sprinkle them on the soil around the affected areas. The scent should fairly effectively repel crawling intruders such as beetles, slugs, cutworms, and ants.
I have also used garlic powder with quite a good effect here. However, this method only works temporarily: the garlic powder is easily removed by rain or regular watering. As a result, the effect of minced or minced fresh garlic is longer lasting, and also more potent/pungent than its powdery counterpart.
Also, if you find mole holes anywhere in your garden, put some minced garlic cloves in them. Moles hate the smell so much they’ll find another place to live now that you’ve soiled their hallway.
soak the ground
I used this method (also known as “soaking”) to treat soil that had previously caused damping off in some of my seedlings. The process involves brewing a large amount of the aforementioned concentrated garlic juice and mixing it with water.
The ratio I use to treat soil is 1 cup garlic juice to 4 gallons of water, but you can dilute it further if you prefer. If you want to relax, use 1/2 cup of garlic juice instead.
Turn the soil or puncture it with a pitchfork. Then pour this liquid generously on the affected area and let it penetrate. Repeat the process daily for at least a week, then allow the area to dry thoroughly, if possible.
As a bonus, this soaking can kill any larvae that may be hiding in the ground. If your lawn has unexplained yellow spots, dig up one of the areas and look for the larvae. If you find any, offer them the garlic dipping treatment mentioned above.
Put garlic to work in your garden
As you can see, garlic is not only an invaluable herbal medicine for humans, but it also does wonders for garden plants and crops!
Be sure to keep potent raw cultivars on hand at all times in case you need them, and when you need them, act fast.
The sooner you use garlic for pest control, whether intruders or fungus, the more likely you are to catch the problem before it gets out of control.
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