How to make a garlic spray – for a natural way to combat slugs on plants

Our outdoor friends come in all shapes and sizes, from the many-legged, the furry and the slimy. Encouraging insects to become a part of our yard's eco system is a great way to help the surrounding environment to thrive. However, it isn't quite so rewarding when slugs start eating our plants.

You don't have to grab an insect spray that will harm or kill slugs if you're facing this issue in your yard though. In fact, by combining garlic with just a few other ingredients, you can create a simple homemade bug spray to spray on your plants and crops that will simply deter slugs away from the area.

Here, two gardening experts in the know about deterring pests share how to make a garlic spray, and explain more about why it's so good at deterring slugs.

Why does garlic deter slugs?

In the world of cuisine, garlic is a strong flavor that most of us have to moderate when making dishes. It's this same pungent aroma that causes slugs to turn the other way when they smell it or begin to taste it on the leaves of your plants.

Ofra Gaito, CEO of Verdant Lyfe Plant Shop, says, 'A chemical called allicin is produced when garlic is crushed or chopped, and it has a strong, pungent odor that repels many insects and pests. The smell of garlic is actually overwhelming to many pests, including slugs, aphids, and even mosquitoes.'

So if you want to learn how to make a garlic spray to protect your plants from slugs, the good news is you can use it to deter other insects at the same time, all without causing any harm.

How to make a garlic spray in 5 simple steps

You will need:

• One head of fresh garlic (a garlic bulb): available at most grocery stores
• Mild natural liquid soap that isn't antibacterial: the Method dish soap in lime and sea salt at Walmart is biodegradable and plant-derived
• One quart of water: you can use the United Solutions 1 quart round measure from Walmart to help measure this accurately
• A blender: the Magic Bullet blender in small on Amazon is the site's top seller and you can use it for so much in the kitchen as well
• A spray bottle like the ones in the 4 pack of mainstays plastic teal spray bottles from Walmart
• A strainer or cheese cloth: using a small fine mesh sieve like the GoodCook ready 6" mesh strainer from Target will do the trick
• A coffee filter or thin cloth: the white coffee filters from Target are great value

Once you have gathered your kit, follow this method:

1. Blend together garlic and water

To begin creating this simple spray solution, first you need to combine the garlic and a quart of water in your blender. Depending on how strong you want the solution to be you can opt for a minimum of four to five individual cloves in the mixture, but it's best to use the entire bulb to prevent slugs from destroying your plants.

'Peel and blend the garlic with one quart of water,' says Jessica Mercer, senior content marketing coordinator and plant expert at Plant Addicts. 'Alternatively, if you don't have a blender and don't wish to purchase one, you can chop the garlic into small pieces to release the essential oils and allicin, and soak it with half the water for a day or two. Add the remaining water in afterwards to continue the rest of these steps.'

Garlic is easy to come by in stores but if you're feeling a bit green-fingered, you can even grow garlic indoors.

Jessica Mercer

Jessica Mercer, PhD, is the Senior Content Marketing Coordinator for Plant Addicts. As a “plant collector”, Jessica enjoys growing many different plants and learning about the best cultural practices for each. Writing for Plant Addicts is a real joy for her, as she can use her science background to research interesting plant topics. She carefully considers how to best present the information to other gardeners, with a focus on sustainability and the environment.

2. Strain the mixture

After your garlic has completely liquefied and combined with the water, you need to strain out any lumps in the solution.

'Strain the mixture through a cheesecloth or fine mesh strainer into a clean bowl to remove solids,' says Ofra. If you skip this step, the garlic solids will clog up the nozzle of your spray bottle, making it difficult to use.

It's optional prior to straining your garlic and water to add in one to two teaspoons of cayenne pepper or a few drops of an essential oil like eucalyptus to boost the fragrant factor of your mixture but it isn't vital for the spray to work.

Target's everspring eucalyptus pure essential oil would be ideal for this as it's not a diluted version of the product.

3. Strain the mixture (again)

To make sure no solids can trap in your spray bottle, running your once-strained solution through a coffee filter will be incredibly helpful.

'Re-straining through a coffee filter ensures no tiny particles remain that might clog the spray nozzle,' says Jessica.

If you notice lumps are still in your garlic solution, keep straining it until it looks smooth. You can use some of your other coffee filters to place at the bottom of plants pots to help retain potting mix in your planters.

4. Add in some soap

Once your mixture is smooth and strained you can optionally add in a small amount of a natural soap. Though this is another optional step, it's one experts would definitely recommend.

'Adding in a teaspoon of mild liquid soap helps the solution to stick better to surfaces or plants,' says Ofra. This, in turn, will improve the staying power of your garlic spray so you don't have to replenish it as frequently (it won't run straight off of the leaves of your plants).

Ofra Gaito

In 2020, Ofra Gaito founded Verdant Lyfe, an e-commerce company born to help and share live plants with both plant lovers and new plant beginners. The company packs and ships hundreds of orders every week to homes and businesses all over the USA. At the head office in South Florida, Ofra and her team conduct workshops every six weeks that involve the plant world. Ofra hosts live radio program Grow Your Lyfe every Friday at 1:45 pm EST on 101.9FM Omega radio.

5. Dilute your mixture and transfer it into a spray bottle

Finally, dilute your garlic mixture before pouring it into a spray bottle to use. If you struggle pouring, investing in a small funnel like the GoodCook ready collapsible funnel from Target will help to prevent any spills, saving you as much of your garlic mixture as possible.

'Make a 1:10 dilution by mixing 1 part garlic concentrate with 10 parts water; then pour the solution into a spray bottle,' says Jessica.

If you have spare pulverized garlic left over you can store it safely in a container with an air tight lid like the ball glass mason jar with lid and band from Walmart.

'Store the garlic that's in a sealed container in a cool, dark spot or in the refrigerator if possible,' says Jessica. 'The spray in your spray bottle will keep for about one to two weeks before losing potency.'

How best to use a garlic spray in the yard

To use your garlic spray, simply transfer the solution into a spray bottle like the ones in the 4 pack of mainstays plastic teal spray bottles from Walmart, and spray it directly onto the leaves of your plants that require protecting.

'Once your solution is ready, shake it well and apply it directly onto plants, around the garden, or in areas where pests are a problem,' says Ofra. 'Avoid spraying during the hottest part of the day to prevent plant damage.'

To stay on the safe side Jessica recommends only using your garlic spray in the evening. Slugs are also around more during that time of the day.

'I recommend applying the spray in the early evening when slugs are active and beneficial insects are less so,' says Jessica. 'Coat both sides of the leaves, repeating every few days or after rain. Continue until no new pest damage is seen.'

Now you know how to redirect the slugs in your yard away from feasting on your plants, perhaps it's time to learn about the benefits they play in your garden ecosystem, as we answer the question - can slugs and snails ever be good for the backyard?