5 Best (and 3 Worst) Companion Plants for Tomatoes

Adding some companion plants for tomatoes is an excellent way to maximize the productivity and health of your tomato plants. Not only that, but picking the right plants could help deter pests and reduce the risk of disease, such as blight.

Alternatively, there are certain plants that aren’t friends with tomatoes and should be left in a different section of the garden. Not all garden plants are friends, believe it or not! They butt heads with each other sometimes, just like humans do.

In this article, we’re going to tackle the 5 BEST and the 3 WORST companion plants to plant alongside your tomato plants so that you have a stress-free harvest this season. Let’s jump in!

*Disclosure: This post may contain affiliate links to products (including Amazon). I’ll earn a small commission if you make a purchase through my link, at no additional cost to you! Regardless, I only link to products that I personally use on our homestead or believe in.

What is Companion Planting?

Companion planting is a gardening method that involves growing plants together to mutually benefit each other’s growth and health, based on the idea that certain plants have properties that can positively influence neighboring plants.

Benefits of companion planting

Create a more diverse and resilient ecosystem
Repelling pests
Providing beneficial nutrients
Improving soil quality
Attracting beneficial insects
Attracting pollinators

Another bonus benefit of companion planting is that it allows you to get away with closer plant spacing – a huge win if you have a small garden!

The 5 Best Tomato Companion Plants

There are some great tomato companion plants out there, but here are the top 5 that will surely help your tomatoes thrive:

Basil
Lettuce
Garlic
Nasturtiums
Marigolds

#1: Basil

Basil is one of my favorites to plant with tomatoes, and for multiple reasons! First, basil is very effective at drawing in the predatory lacewings, which can help eradicate aphid infestations. Not only that, but research shows that basil can enhance a tomato plant’s ability to heal from mechanical wounds.

If you let it go to flower, it will draw in pollinators, which will benefit your whole garden. Some gardeners claim that basil can improve the flavor of nearby tomatoes, however, the research hasn’t quite caught on to that one. Thankfully, basil has compact growth, so it won’t crowd the large frame of tomato plants, either.

#2: Lettuce

Lettuce and tomatoes help each other thrive. Lettuce provides a living mulch around tomato plants, which aids in moisture retention and weed suppression. Then, tomatoes provide nice dappled shade for the lettuce, which will keep it cool and delay it from bolting. Truly a win-win!

#3: Garlic

Garlic does an AMAZING job at repelling pests like aphids and spider mites thanks to its strong-smelling compounds such as allicin. It also doesn’t require very much space – consider planting it around the edges of your tomato beds for a protective border!

If you thought Fermented Honey Garlic was only good for our immune system, guess again! Its antimicrobial properties protect tomatoes from soil-borne diseases, and its antifungal properties protect against things like blight and fusarium wilt. Wahoo!

#4: Nasturtiums

Colorful nasturtiums are a very common companion plant, benefiting almost any plant out there! Plus, they are edible, which is always appreciated. Here’s what they can do to benefit your tomato plants:

Attracts beneficial pollinators
Attracts beneficial predatory insects
Can be used as a trap crop to keep the pests off your other vegetables
Provides a living mulch to reduce weed pressure and moisture loss

#5: Marigolds

Marigolds emit a strong scent that can help deter pests such as nematodes, aphids, and whiteflies, which are common threats to tomato plants. Additionally, marigolds are known for their ability to improve soil health by releasing organic compounds such as thiophenes, terpenes, and flavonoids to suppress harmful soil-borne pathogens and promote beneficial microorganisms.

Lastly, the bright and colorful flowers of marigolds can add aesthetic appeal to the garden and attract pollinators. When strategically planted, marigolds can serve as an amazing companion plant for tomatoes, promoting plant health and pest management in the garden. An excellent choice!

3 Plants to AVOID Planting With Tomatoes

Tomatoes don’t have a lot of enemies in the plant world, but there are a few to pay attention to! Here are the top 3 veggies that I would avoid planting next to your tomatoes at all costs:

Dill
Fennel
Pole beans

#1: Dill

Dill is a frenemy to tomatoes. It can attract beneficial insects, however, it can also draw in the dreaded tomato hornworm – one of the most destructive pests to tomatoes. Plus, dill has allelopathic properties, which means that it can stunt the growth of tomato plants. Lastly, dill can grow to be quite tall and compete with tomatoes for that precious sunshine.

*Check out which companion plants to use with dill in my article: 5 BEST Dill Companion Plants (and 2 to AVOID!)

#2: Fennel

Fennel is a foe to most plants in the garden because it secretes allelopathic compounds that can inhibit the growth of nearby plants (similar to dill!). These compounds may affect the germination, growth, and development of tomato plants, leading to reduced yields.

Lastly, Fennel emits a strong flavor and aroma that can potentially impact the taste of nearby crops, including those delicious tomatoes. Consider planting fennel in its own area to reduce the risk of any off-flavors or an undesirable taste in your other produce.

#3: Pole beans

The challenging relationship between pole beans and tomatoes is more physical than anything else. Both are tall and viney, and if planted next together, you’re going to end up with a tangled mess. Not only will it cause a headache for you, but there will be less airflow from the massive mess, which can lead to disease issues. No thanks!

5 Best (and 3 Worst) Companion Plants for Tomatoes