Garlic and tomatoes go so well in the kitchen that it makes perfect sense to want to grow them in your garden. Growing different plants nearby can have several benefits, but it can spell disaster if they don’t belong together. So is it okay to plant garlic and tomatoes in the same garden?
You can plant garlic with tomatoes because they don’t compete or attract pests that harm each other. Growing them together can even deter harmful pests.
In this article, I’ll show you what each plant needs, what threatens them, and why you’d want to grow them together. We’ll also see what you can do to keep beneficial bugs around.
Garlic and Tomato Plants Don’t Compete With Each Other
Not all plants grow well together. Some have specific watering or fertilizing needs that others don’t, which gardeners cannot meet simultaneously. For example, if a plant grows too tall and wide, it could block the sun from reaching the leaves of a shorter neighboring plant.
As we will see below, garlic and tomatoes can grow well together if planted properly in the same space.
They Have the Same Soil Requirements
For plants to take in nutrients, their soil has to have the correct pH to break down the nutrients. Different plants have different pH requirements, and an acidity-alkalinity imbalance adversely affects microorganism health and plant vitality.
Tomatoes and garlic prefer a slightly acidic pH. Garlic prefers 6.0-7.0, whereas tomatoes like 6.2-6.8. Keeping the soil acidity within this range is relatively easy and will benefit both plants.
They also like high-nitrogen fertilizers. Just make sure the rest of the fertilizer mix works for both crops.
If you’re curious, check out my other article on how to improve the soil for tomatoes: How To Improve Soil for Tomatoes (DIY Guide)
They Have the Same Watering Requirements
Both garlic and tomatoes like plenty of water, but neither likes too much water, which makes it easy to keep them on the same watering schedule. They also prefer soil that drains well, so raised beds work fine, though they can grow quite well in the ground.
They Have the Same Sunlight Requirements
They share sunlight requirements, too, needing full sun (6–8 hours per day) for optimal growth. Given sufficient space around the plants, neither will interfere with the other’s sun exposure. However, larger tomato plants need trellis support to keep them from slumping onto their garlic neighbors.
They Have Compatible Spacing Requirements
Garlic and tomatoes have minimum spacing requirements. Tomato plants need a couple of feet or so between each other. Indeterminate varieties can grow rather large, so prune according to space.
Garlic plants need almost half a foot (15 cm) of separation between them in a row, with rows at least 14 inches (35.6 cm) apart. If intercropping the tomatoes with garlic, check the tomato species’ projected growth to see if you have enough room in your garden.
Garlic Deters Pests That Eat Tomato Plants
Aphids, worms, beetles, mites, and other crawling things threaten the survival of several garden plants. But they dislike garlic. Garlic can repel pests, but concentrated forms may work too well, keeping good and bad bugs away.
Planting Garlic Alongside Plants
Anecdotal, historical, and scientific evidence shows how planting various plants together in the same area (known as intercropping) can produce benefits unavailable when growing one type of plant by itself.
Garlic does not attract pests, and a study showed that garlic plants could be effective in repelling pests (primarily cutworms) when intercropped with cabbage. The intercropped cabbage showed no leaf damage and survived at higher rates than cabbage planted by itself. Cutworms also target tomato plants.
Another study concluded that garlic intercropped with strawberries reduced two-spotted spider mite populations significantly. Spider mites like to eat tomatoes, so the garlic can control those in your garden.
Yet another experiment showed that garlic helped repel aphids when grown with mustard plants. Aphids cause significant damage to tomato plant foliage, robbing your tomatoes of healthy development. They also leave behind mold-attracting fluids, weakening or even killing the plant.
Spraying Garlic Concentrate Onto Plants
Garlic sprays use garlic concentrate mixed with various ingredients—depending on the maker—to saturate an area with a sulfurous smell that harmful bugs find offensive. It is non-toxic and easy to apply.
The Garlic Farm has two handy recipes in a how-to guide for homemade garlic sprays. One for thwarting veggie pests and the other for repelling mosquitos.
Researchers in the U.K. found garlic juice an effective insecticide against house flies and cabbage root flies. However, they noted that garlic concentrations vary amongst manufacturers of garlic sprays, and garlic quality can determine spray effectiveness.
Horticulturalist Noelle Johnson says garlic spray works very well against aphids but cautions that it can also kill or repel beneficial insects. Since beneficial insects pollinate and protect tomatoes and other flowering plants, garlic spray may harm ecosystem health.
Consider your specific needs for controlling pests in your area. Garlic spray may work for you if you can’t plant as many garlic plants, though it may work better to use other plants and garlic plants to attract beneficial insects instead of only trying to repel harmful ones.
Garlic Repels Beneficial Critters That Eat Tomato Pests
Although garlic may repel harmful insects drawn to the tomato plant, it can also repel beneficial critters. Luckily, other plants encourage visits from beneficial insects and arachnids (for clarity, I’m grouping spiders in with the insects).
Beneficial insects prey on harmful ones, acting as natural pesticides. They prey less on important insects like pollinators that service the plants and more on the nasty bugs that destroy them. For controlling aphids, mites, and worms, consider this list of helpful creatures:
- Wasps will eat many tomato-threatening insects and worms. They also work hard to pollinate your garden, plus the flowers of other plants on your property. (If you’re worried about wasps flying around, remember that they don’t attack randomly, only when defending their nests.)
- Beetles like ladybugs and ground beetles prey on aphids, spider mites, and a few worm species. Not all beetle species are helpful, however.
- Lacewings are good pollinators. They also keep tomato plants free of aphids, destructive beetles, mites, thrips, and leafminers.
- Spiders love to spin webs amidst tomato stalks and branches, trapping moths, thrips, and flies. However, they don’t depend on webs, patrolling the garden for mites, fleas, and aphids.
Plants That Attract Beneficial Critters
Beneficial insects come to your yard for the same reason harmful ones do: food and reproduction. As for food, the good creatures scan plants for pollen and nectar to draw them in for closer looks. Once in the area, they also hunt for the pests that threaten your plants.
To maximize the efficacy of the attracting plants, you’ll want to intercrop them with your garlic and tomatoes. Doing so creates an ecosystem of multiple beneficial species working together.
Intercrop these flowers with your garlic and tomatoes to attract helpful anti-pests (check that a species doesn’t fall on the invasive list in your region before planting):
- Coreopsis flowers. They grow strong in many soils and attract lacewings, ladybugs, ground beetles, and wasps.
- Cosmos. They attract lacewings and ladybugs. They like full sun and bloom in multiple colors to draw broad ranges of pollinators.
- Marigolds. They attract ladybugs, praying mantids, and many other pollinators, but they also repel tomato-eating nematodes.
These flowers attract spiders to the garden because they and the tomato plants give arachnids plenty of stalky stems and branches to weave their webs. Spiders visit plants to catch prey, and they don’t distinguish between helpful or harmful insects, but they aren’t so numerous as to impact beneficial populations.
If you can’t plant more plants alongside garlic and tomatoes in the garden, you might house them in a separate container (or bed) nearby. By learning to identify beneficial insects and other lifeforms, you can maintain the best environment for optimal plant health.
Garlic and tomato plants grow just fine together in the same garden because they share growing requirements and don’t compete.
Several studies and anecdotal evidence show that garlic planted alongside tomato plants deters several pests. A two-pronged system using pest-deterring intercropped garlic alongside beneficial insect-attracting plants can control most tomato-loving pests.