I think it’s safe to say that tomatoes are the apple of every gardener’s eye.
Nothing beats a big, juicy tomato fresh from the garden, and nothing screams “I’m a great gardener” than a plant loaded with tomato fruit on the Fourth of July.
What’s the secret to happy tomato plants? (Hint, check the title.)
It’s companion planting.
Companion planting transforms a boring little tomato patch into a thriving ecosystem. When you grow the right plants together, you’ll find healthier tomstoes, fewer pest issues, more efficient use of space, and a garden so breathtakingly beautiful, you’ll never want to leave.
Too good to be true? Grow a garden and find out for yourself. 😉
In this post, I’ll share the best companion plants for tomatoes (based on what actually works in my garden) and help you see why companion planting is so great for the garden.
New to growing tomatoes? Start with my complete guide to growing tomatoes from seed to harvest to learn the basics, then come back here to make your tomato garden even better.
Why Companion Planting Works
Companion planting isn’t too good to be true. It’s just working with nature rather than against it.
Think of gardens as a community. In a community, different people contribute different things. Bakers make bread, farmers grow food, and doctors take care of sick people. Everyone has different needs and skills and the community thrives because of each person’s contributions.
When we grow different plants together strategically they:
1.Support each other’s growth. Some plants have shallow roots, while others go deep, so they’re not competing for nutrients and water. Tomatoes have relatively shallow roots, while carrots grow straight down. They can share the same bed without fighting.
2. Confuse and deter pests. Mixing diffferent secents and palnt types makes it harder for pests to find their target plants. A hornworm looking for tasty tomato leaves has a harder time when basil and marigolds are sending their scents out into the ether.
3. Attract beneficial insects. Some plants are magnets for pollinators and pest predators. Even though tomatoes can self-pollinate, they set fruit more reliably with the help of bees. And inviting beneficial insects are always helpful for a garden. See my post on practical reasons to grow flowers in your veggie patch for more on this idea.
4. Make efficient use of space. Quick-to-harvest crops like lettuce can fill the space around young tomato plants and provide an extra harvest in the same space before the tomatoes get big enough to need that room.
And the result is beautiful. A more productive, resilient garden that helps itself grow. This is exactly what it’s like to work with nature instead of against it.
The Best Companion Plants for Tomatoes
A little fact you should know about me is that I don’t like confining plants to lonely little rows like soldiers marching off to their deaths. I like my gardens to look and feel lush, and for every empty spot to be growing something beautiful or useful.
So although I grow lots of tomatoes each year, I don’t plant them all together in one spot. I spread them out and fill the space around them with companion plants. These are the plants I like to grow with my tomatoes.
Herbs and Flowers for Beneficial Insects
Basil
This is a well-known tomato companion, and for good reason. Basil can repel aphids, whiteflies, and some gardeners say it helps deter hornworms (though I still hand-pick those green monsters regardless). Basil is also said to improve the flavor of tomatoes. I’m all for that!
Plant basil 8 inches away from tomato plants. It will benefit from being in the shade of the tomato plant.
For a fun pop of color, try planting Purple Ruffles Basil or Dark Opal Basil. Same benefits, different color.
Marigolds
Marigolds are well known for deterring all sorts of pests, and while the science is iffy, one thing’s certain: their roots release compounds that suppress root-knot nematodes (microsopic worms that damage tomato roots). Cheerful, easy to grow from seed, marigolds are hard not to love!
Sweet Alyssum
This low-growing flower is one of my favorites of all time. Not only is it edible, but it also creates a living mulch around tomato plants, suppressing weeds while attracting beneficial insects like lacewings and hoverflies. These good bugs eat aphids, thrips and other baddies. Plus it’s honey-like scent will fill your garden with sweetness.
Alyssum tolerates shade and will stick around even after a few frosts. Plant it as a border around your tomato bed or tuck it into corners of raised beds and allow it to spill out like a fountain.
Nasturtiums
Nasturtiums are a trap crop for aphids. Aphids love nasturtiums and will flock to the plant’s tender stems instead. You can then either remove the affected stems and leaves or leave them for beneficial insects to feast upon.
Nasturtium flowers and leaves are edible… though you’ll probably want to check for aphids before you pop one straight into your mouth.
Calendula
Calendula attracts pollinators and beneficial insects while adding glowing orange and yellow blooms to your garden. The flowers are edible and have medicinal uses. It’s great for your skin.
This flower reseeds readily and will produce the most blooms if deadheaded regularly.
Zinnias
Zinnias bring an explosion of color to the garden and attract butterflies, bees, and other pollinators. They’re one of my favorite cut flowers to grow.
I love planting zinnias throughout my garden, and they pair nicely with tomatoes, adding a beautiful backdrop. For more on growing zinnias, read my guide on how to grow incredible zinnias from seed.
Vegetables to Companion Plant with Tomatoes
Cucumbers
This one surprised me, but cucumbers and tomatoes actually grow well together. My best cucumbers were the ones grown next to a tomato plant. Yes, they’re both heavy feeders, but a few handfuls of compost or fertilizer at planting and midway through the season will keep them both happy.
I usually grow cucumber on a trellis and an indeterminate tomato alongside. They both grow up the sturdy trellis together, BFFs for life. You can also grow bush cucumbers near the base of an indeterminate tomato that’s caged or staked upright. Keep the two 12-18″ apart. Don’t crowd them.
Lettuce
Lettuce is a great early-season companion. I direct seed them in mid-spring around the perimeter of a bed and plant tomato transplants in the center of the bed in late spring. The lettuce grows quickly and usually bolts before the tomatoes get too big. It’s a great way to use space that would otherwise have just been bare soil.
This method is called succession planting, or intensive planting. Having a second crop follow right on the heels of the first crop to maximize every square inch of a bed.
Carrots
Carrots have deep taproots that grow straight down, while tomatoes have shallow, spreading roots. They’re taking nutrients from different soil layers, so they’re not competing. This principle applies to most companion plants. Companion plants take up different spaces under the soil or above the soil and thus, grow well together.
As with lettuce, I plant carrots in early to mid-spring around the edges of where my tomatoes will go in later. Tomatoes have room to go in the center and as I harvest carrots, there’s more room for tomatoes to spread out.
Green Onions
Green onions, or bunching onions, are an easy crop to squeeze in almost anywhere. I start these in late winter and just tuck them in whereever I have an empty spot. The strong scent of onions can help shoo pests away from tomatoes, and because green onions are quick to grow and don’t require a lot of space or nutrients they make a great companion plant for tomatoes.
Garlic
Garlic is planted in the fall where I live, and if I leave plenty of space, I can usually plant tomatoes among the garlic in the spring before the garlic finish. Garlic’s strong scent may help deter pests and it uses the space during a different season than tomatoes.
Planting garlic as a companion plant for tomatoes is an example of thinking about your garden across time AND space.
More in the Cottage Vegetable Garden Series
- What Is a Potager Garden (And Whay It’s the Only One You Need)
- Potager Garden Design: 8 Elements for a Kitchen Garden you’ll Never Want to Leave
- 9 Herbs for Flower Arranging to Add Fragrance and Texture
- 18 Great Companion Flowers for Vegetables
- 9 Practical Reasons to Grow Flowers in Your Veggie Patch
What NOT to Plant with Tomatoes
Not all plants make good neighbors. Avoid planting these near your tomatoes:
- Squash and Pumpkins: These are heavy feeders and will compete for nutrients with tomatoes.
- Big Brassicas (broccoli cabbage, cauliflower): Also heavy feeders that may outcompete tomatoes.
- Fennel: Allelopathic, meaning it releases compounds that inhibit the growth of nearby plants, much like black walnut
- Potatoes: Potatoes and tomatoes are both nightshades and susceptible to the same diseases like blight.
From this list we can draw some conclusions about deciding if a plant would be a good companion for tomatoes.
Ask yourself: Is this plant a heavy feeder? Is it a nightshade like tomatoes?
If the answer is yes to either of these, then don’t plant it near your tomatoes. Plant smart and your garden will take care of itself.
Tips for Planting Companions with Tomatoes
I mentioned these above, but here’s an organized list of layout ideas for planting companions with your tomatoes:
The Border Method: Plant tomatoes at their regular spacing (18″ apart for pruned and staked plants, 24-36″ apart for cages), then edge the bed with your chosen companion. I like to do this with spring plants like lettuce and carrots, and low-growing flowers.
The Interplanting Method: Tuck companion plants in between tomato plants. You may want to space tomatoes further apart so everyone gets what they need to feel comfortable. I use this method mostly with basil, zinnias, and cucumber.
The Understory Method: Plant low-growing companions like sweet alyssum and nasturtium at the feet of tomato plants, using them as a living mulch.
As always, give tomatoes room to breathe. They’re the star of the show. You don’t need to sacrifice their health so the side characters can shine.
Good airflow keeps disease at bay and good spacing allows roots to spread. Companion planting doesn’t help if plants are too close together.
Ecosystem Thinking for Gardeners
Companion planting is a lesson in thinking about ecosystems. Gardens are mini, highly managed ecosystems after all.
When you start noticing which plants help each other, you’re learning to see your garden as an interconnected web instead of individual plants in neat rows.
Things like space allocation, crops that thrive at different times during the growing season, plants that serve different purposes (deterring pests, attracting pollinators), and seeing where one plant struggles while others thrive all help you become a better gardener.
It’s something I’m learning more and more about each year through experience and occasionally, some research!
I hope to keep sharing the things I’m learning to inspire you to grow your gardening skills alongside me.
Your Turn to Grow
It’s your turn to start companion planting with your tomatoes.
Keep it simple. Pick one herb, flower or vegetable to start with.
Observe what happens and let me know how it went for you!
Comapnion planting is an experiment, and every garden is different. What works great in my garden might need some adjustment in yours. We have different soil, climate, pest pressures, and different ways of gardening.
The best gardens are the ones that fit the way we like to grow.
Ready to grow your best tomatoes yet?