A Guide to Companion Planting for Your Vegetables

Plants don’t thrive in isolation—they need friends (just like us). One common theory touted by a number of master gardeners says that pairings of certain plants will help them thrive, while other combinations can impair the process. 

Otherwise known as companion planting, the University of Massachusetts Amherst outlines the different approaches and benefits of certain plant pairings such as managing pests and maximizing yield. Compatibility is said to be dependent on a number of factors like the types of nutrients plants take from the soil as well as the look or smell that certain plants give off. 

It’s important to note that while there have been a number of books, guides, blog posts and articles written about this notion of companion planting, there is some difference in opinion on what works best due to it being largely based on anecdotal evidence. What we’ve done for you is put together a list that outlines consensus on a number of recommended arrangements as well as pairings to stay away from. 

So even though it might not be the time to go out and mingle with your friends during the pandemic, you can live vicariously through your garden and give your plants some buddies.

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Tomatoes:

Pair with: basil, onion, asparagus, carrot, parsley, cucumber, garlic, parsley, carrots, celery, chives 

Avoid: fennel, broccoli, cabbage, corn, potatoes, eggplant, peppers, dill 

Notes: Basil is particularly efficient in helping produce greater yield in addition to repelling insects. Carrots have also been said to enhance the taste of tomatoes, but it’s common that tomatoes don’t grow as large as they should. 

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Carrots 

Pair with: beans, brassicas, chives, leeks, lettuce, onions, rosemary, tomatoes, sage  

Avoid: dill, parsnips, potatoes 

Notes: Chives have been known to improve the taste and texture of carrots. Chives, along with leeks and onions are good for pest control like aphids and carrot rust flies. 

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Garlic

Pair with: beets, brassicas, celery, lettuce, potatoes strawberries, tomatoes 

Avoid: peas, beans

Notes: Garlic is a helpful pest repellent for many plants, but if you mix it with peas or beans, it will stunt their growth.

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Lettuce

Pair with: beets, brassicas, carrots, cucumber, dill, garlic, onion, radish, spinach, squash, strawberries

Avoid: Lettuce gets along with everyone! The consensus seems to be that there are no specific plants detrimental to the development of lettuce.  

Notes: Lettuce is an effective cover crop for taking care of weeds when planted with beets. Its shallow roots make it a good match for root veggies like beets and carrots in terms of maximizing space because it grows above the soil. Garlic will be efficient in protecting your lettuce against aphids. 

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Onions

Pair with: beets, brassicas, carrots, strawberries, tomatoes, lettuce 

Avoid: peas and beans 

Notes: Like garlic, onion is another valuable pest protectant. It deters aphids, Japanese beetles and rabbits, but has the same impact on peas and beans with stunting their growth. 

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Corn 

Pair with: beans, cucumbers, squash, potatoes, peas 

Avoid: tomatoes 

Notes: The “Three Sisters” companion method is a well known Native American approach with corn beans and squash. Squash leaves act as a soil cover and pest deterrent. The beans provide the soil with nitrogen, which then helps the corn grow. When the corn stalks grow, they act as a trellis for the beans. 

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Potatoes

Pair with: beans, brassicas, corn, 

Avoid: tomatoes, squash, cucumber 

Notes: Corn, beans and brassicas are all good choices to be planted next to potatoes because they all grow above ground and will allow you to maximize your garden space. 

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Brassica (Broccoli, Cauliflower, Kale, Collards, Cabbage): 

Pair with:  beans, beets, onion, potatoes, oregano 

Avoid: strawberries, tomatoes, peppers, squash 

Notes: Beets have been known to enhance the taste of brassica crops while onion will be a helpful pest deterrent. Nightshade crops like tomatoes and peppers attract pests that are harmful to the brassica family. 

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Green Beans

Pair with: beets, brassicas, carrots, corn, cucumber, peas, potatoes, strawberries

Avoid: chives, leeks, onion, garlic 

Notes: Potato plants can help as a deterrent to beetles. As explained in the Three Sister method, corn is particularly useful to beans, making use of garden space and acting as poles for the beans to grow upright. 

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Radishes

Pair with: beans, cucumber, lettuce, peas, squash, spinach, carrots 

Avoid: potatoes 

Notes: Cucumbers can improve the growth of radishes while radishes keep the cucumbers protected against rust flies and beetles. Despite the fact that radishes and carrots are both root crops, radishes germinate more quickly which then makes space for carrots that develop later.