Garlic Companion Plants | Garden Friends and Foes

Using garlic as a companion plant is far from revolutionary. Many gardeners already know that planting this pungent-smelling allium can fend off pests and improve the health of nearby plants. 

Another part of what makes garlic so well-suited to companion planting is that it takes up minimal space and thrives in nearly any decent soil. So there’s little work or sacrifice involved in adding this vegetable to an existing garden.

In this article, I’ll tell you how to grow the best garlic companion plants and achieve proven results along the way.

What Is Companion Planting?

Companion planting is a gardening method where you grow two or more kinds of plants together in the same plot. Many people use this technique because they want to achieve some benefit, like pest control, without using chemicals. But this is just one example of why companion planting can be helpful.

Companion planting has a rich history that can be traced back to various cultures around the world. The most famous example — known as the ‘Three Sisters’ method — was developed by American Indians long before European colonists arrived.

In a Three Sisters garden, you have corn, pole beans, and squash. These plants are grown practically right on top of each other and have the following relationships:

The pole beans climb the corn and transfer available nitrogen from the atmosphere into the soil.

The corn provides a tall structure for the beans to climb and is less likely to be damaged by strong winds thanks to the beans acting as an anchor.

The squash fills the space near the ground with its large leaves, shading the soil to keep it cool and retain moisture.

I love highlighting the Three Sisters method because it perfectly showcases the power of combining different plants to build a miniature ecosystem. And, while it is 100% human-designed, it borrows a lot of inspiration from plant relationships seen in nature.

How Growing Garlic Affects the Garden

Garlic is an incredibly potent vegetable with a long list of culinary uses. Its acrid odor is so strong that using garlic as a vampire repellent is semi-believable! It’s also why so many gardeners turn to garlic to protect their more vulnerable crops from pest damage.

Admittedly, I’m a real skeptic when it comes to gardening hacks and shortcuts. Most evidence supporting garlic’s benefits is anecdotal and should be taken with a grain of salt. But there have also been some promising studies published on the subject.

Here’s a quick overview of potential garlic benefits that seem to be more fact than fiction:

Garlic naturally deters pests. Garlic reportedly decreases pest activity when interplanted with other edible crops. 

Studies have been conducted using various plants and monitoring several different pest species. The results are mixed but do support the claim that garlic deters pests to some extent. However, the big (unanswered) question is whether garlic is enough of a deterrent to be worth planting for this reason alone. 

We also don’t know for sure which pests garlic works on. Studies have been conducted on two-spotted spider mites, cabbage moths, green peach aphids, and cabbage aphids.

Garlic may increase nutrient availability. There have been a couple of studies showing that vegetable crops interplanted with garlic have higher concentrations of some nutrients — e.g., nitrogen, phosphorus, potassium, and calcium — than those grown alone. 

This might not always be a good thing, however, since interplanting with garlic also decreased select nutrient levels.

Garlic may alter the number and quality of soil microbes. One of the most interesting things garlic does is manipulate the microbes in the surrounding soil. 

Planting garlic seems to increase bacterial activity (remember that bacteria is not always good or bad) in the soil. This could directly impact the growth of other crops nearby.

Research also shows that soil-borne fungi are less prevalent around garlic, likely due to the vegetable’s high sulfur content. But there’s currently no proof that growing garlic will prevent fungal diseases in neighboring plants.

Growing garlic can impact the yield of other crops. This is a common claim and some scientific research has been done. The evidence suggests that interplanting garlic might result in a larger harvest but only just.

Best Garlic Companion Plants

Garlic is usually planted in the fall from individual cloves and then harvested sometime the following summer. The bulbs need a bit of breathing room to develop properly but otherwise don’t take up much space at all.

Garlic benefits from a good dose of nutrition early in the growing season. This helps kick-start healthy bulb development. Fertilizing too late in the year can cause the garlic to prioritize leafy growth instead.

All in all, garlic is easy to grow and gets along well with a wide variety of plants. You can readily interplant garlic with a number of fruit, vegetables, herbs, and ornamentals. Just remember to keep your garlic needs in mind as well.

Fruit and Vegetables

Apples, Peaches, and Other Fruit Trees: Garlic is a popular companion plant for a variety of fruit trees because it’s believed to deter insects and fungal diseases. 

Common pests that garlic might protect against include aphids and peach borers. The pungent bulb supposedly prevents diseases like scabs and leaf curls in fruit trees.

Though I wouldn’t rely on garlic alone to protect your apples or peaches, no harm will come from planting it around your trees. 

Tomatoes: Garlic and tomatoes will happily coexist in the same garden bed. Growing the two side by side can even make harvesting a bit easier since so many recipes call for both ingredients. However, the biggest potential benefit of this partnership is garlic’s ability to deter spider mites. 

Brassicas: The brassica family includes important vegetables like cabbage, broccoli, kale, and cauliflower. Many gardeners believe that growing garlic near their brassica crops will deter nasty pests like cabbage moths, cabbage loopers, and aphids.

Eggplant: Eggplant is a delicious crop that is unfortunately very prone to pest damage. Interplanting your eggplant with garlic bulbs may decrease the number of aphids and other pests in the garden.

Peppers: Garlic’s natural insecticidal properties could protect peppers from pests and diseases. Peppers were one of the crops studied to determine the ways in which garlic alters the soil biome and nearby plant health.

Carrots: The smell of garlic is strong enough to cover up the sweet aroma of nearby carrots. This makes it harder for the nasty carrot root fly to find its dinner.

Potatoes: Planting garlic is a potential way to keep common pests like aphids and spider mites away from your potato crop.

Beets: Though it seems counterproductive to grow two root crops side by side, garlic, and beets have very different growth habits. Garlic roots reach less than 2 feet deep. Beetroots, on the other hand, extend at least 3 to 4 feet below the soil’s surface.

Planting these vegetables in the same garden is both a good use of space and might keep pests away from the beets’ foliage.

Spinach: Spinach is a good garlic companion in many climates because both crops enjoy cool weather. Interplanting the two offers benefits like pest control (from the garlic) and weed suppression (from the spinach).

Lettuce: For the same reasons as spinach, lettuce is a great companion plant for garlic. Try planting alternating rows of garlic and lettuce to make the most of your garden plot.

garlic and lettuce
Garlic companion plants with lettuce and beets

Celery: Celery is in the carrot family, so can also benefit from garlic’s ability to fend off carrot root flies and similar pests. I’ve also heard that growing garlic in the same bed makes celery taste sweeter but have found no solid evidence to prove these claims.

Herbs

Basil: In addition to both crops deterring pests, many people believe that growing garlic and basil together can improve the flavor of each. Try this combination in your own garden and let me know what you think!

Dill: Dill is a tough herb that few pests bother with. However, aphids can still be a problem. Garlic may protect your dill from aphid attacks while benefiting from its flavor-boosting properties. 

Chamomile: Chamomile releases certain chemicals — e.g., flavonoids and coumarins — that benefit the soil and surrounding plant life. Growing chamomile in conjunction with garlic can improve the overall health of your garden.

Tarragon: Like chamomile, tarragon plants produce beneficial biochemicals that can boost the growth of garlic and other crops. Garlic may be effective at keeping spider mites off of your tarragon. 

Summer Savory: Summer Savoury is a member of the mint family that may offer some pest-repellent properties of its own. It also improves the health and flavor of nearby crops by releasing chemical compounds into the soil.

Flowering Plants

Rose: Garlic has long been used as a companion plant for roses. Rose bushes often fall victim to pest damage and fungal diseases, which garlic supposedly protects against.

Nasturtium: Nasturtiums are often used as a trap crop to lure aphids away from other plants. Planting garlic nearby could add an extra layer of protection for more vulnerable crops in your garden.

Marigolds: Garlic and marigolds may have a mutually beneficial relationship when planted together. Marigolds are known to deter nematodes (roundworms) in the soil, while garlic deters certain airborne pests.

Yarrow: Sometimes grown as a herb, yarrow is a wildflower native to many parts of the world. It’s commonly added to edible gardens as a way to attract beneficial pollinators and predatory insects. Growing both yarrow and garlic is a great strategy for increasing biodiversity in your garden.

Rue: Rue was once used in herbal medicine but has fallen out of favor in modern times. It’s still very useful though as a companion plant that deters pests insects and other forms of wildlife. When grown with garlic or other alliums, it’s believed that rue will control onion maggots.

What Not to Grow with Garlic

Don’t be fooled by garlic’s seemingly miraculous benefits. There are quite a few crops best kept on the opposite side of the garden.

It’s believed that planting garlic nearby will stunt the growth of popular vegetables like peas, beans, and asparagus. Similarly, culinary herbs like parsley and sage tend to grow less vigorously when planted near a garlic crop. 

Attempting to grow strawberries and garlic in the same bed may reduce the total fruit harvest, according to an Egyptian study published in Acta Horticulturae.

We don’t really know why garlic affects crops in this way while seeming to boost the growth of so many others. In many cases, the most likely explanation is that the garlic is simply competing against the other plants for resources (e.g., moisture and soil nutrition). 

It’s also possible that garlic’s sulfur content or the way it manipulates soil microbes has a negative effect on select plant species. There’s even evidence that garlic releases strong allelopathic compounds into the soil which prevent some plants from growing.

If you enjoyed this article, why not take a look at Mint Companion Plants by clicking this link.

Citations

  • Acta Horticulturae – Strawberry Intercropping With Some Vegetables For Economic Productivity
fc0f28385ebd56da36c2bbe134f43736?s=150&d=mp&r=g
 | Website

Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.