Tomato Companion Plants For Your Organic Garden Patch

Ilona Erwin

You might know that “carrots love tomatoes”, but are you aware of those plants which help give you flavorful healthy tomatoes, or deter common garden pests? This post is to guide you in some companion planting benefits.

First, what is companion planting? It is growing plants together for the most mutual benefit. It might surprise you to know that plants may produce chemicals that either help or hinder other plants.

Usually when we say “companion planting” we mean those which help each other, but it can also mean knowing which choices could harm the growth of your intended crop.

Companion Planting Cheatsheet

There are several concepts in this type of growing method that include those that actually attract pests. The idea is to attract them away from your food onto those that you gladly sacrifice. Nasturtiums, Mustard, and Alfalfa are used this way.

Use these flowers and herbs to improve your harvests this season.


Tomatoes And Marigolds

marigolds are easy seeds to plantI always plant marigolds with my tomatoes, they not only make a pretty border, and are easy to grow from seed, but they suppress nematodes. 

Nematodes are microscopic, but they can do big damage to tomato plants,causing them to be stunted, to wilt, or die. Marigolds are proven to suppress the plant-parasitic nematodes.

What Kind Of Marigolds?

Be sure to plant Tagetes spp. , but French marigold types (T. patula) are both the best and prettiest to use.

It is most effective if you not only sow them alongside the tomato plantings, but plant the whole soil area the season before. I haven’t done that, but intend to experiment this year. The most economical way is to use seed, rather than started plants. It will make a cheerful patch of yellow and orange in a kitchen garden.


The way this plant companion works is called “allelopathy”. It releases substances into the soil which help reduce root-knot nematodes and other disease promoting organisms. (1)

Tomatoes And Basil

Basil is an essential herb to grow for both taste and health. It also has a reputation for improving the flavor of tomato fruits, if grown nearby. It is supposed to help the plants grow more lustily- though I am not sure I have noticed this effect.

It is well known that stack of tomato slices with medallions of fresh mozzarella cheese, and a fresh basil leaf is one of the most delicious summer snacks you will make!

Aromatic herbs like Basil often repel pesky insects like thrips and aphids.

Parsley, Tomatoes, And Peppers


rotate your crops each year

This is a classic combination for me. I use them together in cooking and they seem to help each other in the garden.

Closely related, tomato and peppers are part of the same family, Solanaceae. This means you can plant them together but not in consecutive rotation.

The large leafy Solanum lycopersicum, better known as “tomato”, helps protect the peppers, Capsicum frutescens. Peppers like some sunshine to fruit and produce well, so don’t let the tomatoes hog it all.

Tomato Troubles

More Herbal Friends

Besides Basil and Parsley, there are more herbs to grow within the area of your tomato plants. Try some Borage, whose sky blue flowers and cucumber flavored leaves are said to repel hornworms. You know, those gigantic green worms that can decimate the leaves on your plants, almost before you know they are there?

I would still check for the hornworm and pick them off as soon as you find them.

Mint nearby is useful. Heed the warnings of its power of spreading in the most unruly way. I grow it in a raised bed, but perhaps containers of it are wiser than allowing it to root in your vegetable beds.

Chives can also help repel aphids, although our ladybug friends keep numbers down.

Another Way To Skin A Cat

Just kidding…we don’t do that here, but an alternative to repelling insects is to attract them to an area away from your favored food plants.

Nasturtiums are catnip to aphids (so to speak), drawing great hordes of them to their juicy stems, leaves, and flowers. Using them as a trap crop to lure them away from your tomato plants is one way gardeners protect their harvest crop.

I just plant Nasturtiums because they are so attractive (I think I made a pun, there!). Does that make me shallow, to love a decorative kitchen garden? I think I am more likely to take care of the weeding, and other chores when my garden delights me… Do the addition of flowers among your veggies affect you that way?

How And Why Of Companion Planting


Which Plants Are Bad For Tomatoes?

While we are on the topic of plants which are friendly, why not a word about those which are bad company?

I recall the struggle my mother had trying to grow decent tomatoes in a yard that also harbored a great Black Walnut tree (Juglans nigra). Wherever its roots reached, it deposited the toxin juglone, and the tomatoes suffered for it.

Fennel is known to stunt the plants growing around it.

Cabbage family inhibits the growth of this plant.

Potatoes, in the same family, also are susceptible to some of the worst  problems like early and late blight; so it is best to separate them, and make sure your crop rotations discourage passing on these plant killers.

So that sums up the most effective of the companion plantings for your prize tomatoes. If you have additional tips or noticed good results from specific plants that grow well alongside your veggies and help them- please spill the beans.

I know. I can’t help myself once the puns and wordplays begin.


If you want to grow your tomatoes from seed, see How To Care For Tomato Plants which provides 5 quick tips to start from seed.
All About Tomatoes
Tomato Variety Review

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Ilona Erwin, author

Meet the Author

Ilona Erwin

I started working on this website beginning in 1998, when it was part of Ilona's Reflecting Pool. Since then I've branched out into a number of online endeavors and work at writing lots of content for my sites. "Ilona's Garden" remains my primary site and is dedicated to home gardener's success.