The Best Companion Plants for Tomatoes (And What NOT to Plant Nearby)

This post contains affiliate links. If you make a purchase through these links, I may earn a small commission at no extra cost to you.

If you’ve ever had tomato plants that looked weak, struggled with pests, or barely produced fruit, companion planting might help more than you think.

I used to think companion planting was just one of those “old gardening myths” people repeated online. But after experimenting with different combinations in my own garden, I started noticing real differences — especially with pests, airflow, and overall plant health.

The good news is you don’t need a huge garden to make companion planting work. Even a few well-paired plants can make your tomato bed healthier and easier to manage.

Here are some of the best companion plants for tomatoes, plus a few plants you’ll definitely want to keep far away.

What Is Companion Planting?

Companion planting simply means growing plants together that benefit each other in some way.

Some companion plants:

- help repel pests

- attract pollinators

- improve soil health

- provide shade or ground cover

- maximize garden space

And honestly? Some combinations just seem to make tomatoes happier.

Best Companion Plants for Tomatoes

1. Basil

This is probably the most popular tomato companion plant — and for good reason.

Basil may help repel pests like aphids and hornworms, and it’s incredibly easy to tuck between tomato plants.

Plus, tomatoes and basil just belong together.

I usually plant one basil plant near every tomato cage.

If you want an easy starter variety, Genovese basil is one of the simplest to grow.

2. Marigolds

Marigolds are one of my favorite “workhorse” flowers in the garden.

Not only do they brighten everything up, but many gardeners swear they help deter nematodes and other pests.

I plant marigolds along the outer edges of my raised beds every year.

Bonus: pollinators absolutely love them.

3. Garlic

Garlic has a strong scent that may help confuse or deter common garden pests.

I especially like planting garlic near tomatoes in smaller gardens where pest pressure can build quickly.

Even if it doesn’t magically solve every pest problem, it definitely doesn’t hurt.

4. Lettuce

Lettuce works surprisingly well around tomatoes because it acts like a living mulch.

The lower leaves help shade the soil and retain moisture during hot weather.

I’ve had good luck planting leaf lettuce around the base of larger tomato plants once summer temperatures start rising.

5. Nasturtiums

Nasturtiums are beautiful, easy to grow, and incredibly useful in the garden.

Many gardeners use them as a “trap crop” because aphids tend to flock to them instead of vegetables.

They also attract pollinators and add a ton of color to the garden.

If you like cottage-style gardens, nasturtiums are such a fun addition.

What NOT to Plant Near Tomatoes

Not every plant makes a good tomato neighbor.

Here are a few plants I try to keep separate whenever possible.

1. Corn

Corn and tomatoes attract some of the same pests, especially tomato fruitworm.

Planting them close together can sometimes create a pest magnet situation.

2. Potatoes

Since tomatoes and potatoes are both in the nightshade family, they’re vulnerable to many of the same diseases.

Keeping them apart can help reduce the spread of fungal problems.

3. Fennel

Fennel is one of those plants that tends to dislike company in general.

It can inhibit the growth of nearby vegetables, including tomatoes.

I usually keep fennel in its own separate container or corner of the garden.

My Favorite Simple Tomato Companion Layout

If you’re not sure where to start, here’s a super beginner-friendly setup:

- Tomato plant in the center

- Basil planted nearby

- Marigolds along the border

- Lettuce around the base

Simple, productive, and easy to maintain.

Helpful Supplies That Make Companion Planting Easier

One thing that helped me organize companion planting better was switching to sturdy plant markers instead of trying to remember where everything was planted.

Something simple like garden markers can save a surprising amount of confusion later in the season.

I also love using tomato cages early before plants get out of control.

Heavy-duty cages are worth it if your tomatoes tend to flop over mid-summer.

Final Thoughts

Companion planting isn’t magic, and it won’t completely eliminate garden problems overnight.

But in my experience, it absolutely helps create a healthier, more balanced garden.

Even small changes — like adding basil or marigolds near your tomatoes — can make your garden feel more productive and easier to manage.

And honestly, experimenting is part of the fun.

Every garden teaches you something new.

Happy planting 🌱