7 Common Vegetables that Should Not be Planted Together (2024)

I remember being in third grade and my teacher separated two of the annoying boisterous kids (okay, one of them was me), and said: “You two just can’t be around each other!” We were constantly distracting others and getting into trouble. Well, not unlike a couple of disruptive 8-year olds, there are vegetables that should not be planted together.

Some reasons to separate certain plants are obvious. Like if there’s a major size difference and the taller of the two may make too much shade for the shorter plant. Or the plants may have differing water and fertilizer needs, so when you give one vegetable its proper amount of water, the neighboring plant gets oversaturated and rots.

Some vegetable plants are so alike that they are susceptible to the same diseases.And sometimes plants are toxic to each other (like that high school friend that told you you needed a nose job – you don’t, by the way, you’re perfect!). These plants have chemical properties that stunt the growth or even kill the plants surrounding them. The whole thing is called allelopathy.

Below are seven common vegetables that should not be planted together, and the reasons why.

Carrots

Don’t plant carrots next to dill because they’re from the same family of plants which causes them to cross-pollinate. This ends up stunting the growth of the carrots. Similarly, carrots should not be planted next to turnips.

Potatoes

Potatoes are the third-grade bully. They have problems with everybody! Cucumbers, melons, squash, turnips, all fall victim to the potato and its competition for nutrients and moisture. Even members of the potato family, like the tomato, shouldn’t be near the potato because they slow the growth of each other and can be more susceptible to potato blight (Phytophthora). Best to keep these veggies in the corner!

Asparagus

Asparagus is the lone wolf of the class. He’s pretty cool. He wants his space and definitely doesn’t want to hang out with onions, garlic, or potatoes. And no, he doesn’t want to sign up for after-school art classes, either. Gosh!

Pole Beans and Peas

All types of pole beans can cause problems for plants like peppers (all varieties) and even beets. These combinations don’t work well because they compete for resources. These are vegetables that should not be planted together.

Broccoli and Cauliflower

I think it’s funny how picky broccoli and cauliflower plants can be while growing next to certain types of vegetables, given how picky humans are in eating them! Broccoli and cauliflower won’t do well near peppers, tomatoes, squashes, or strawberries. Technically if you really enrich your soil they can be friends, but in general, brassicas soak up all the nutrients in the soil which makes it hard for other nutrient-needing plants to thrive.

Corn

Planting corn too close to tomatoes is like when moms used to have chicken pox parties in the 80s. Corn and tomatoes are both susceptible to fungal infections and if one gets it, the other one will too. They’re also both susceptible to pests like the cotton bollworm so it’s best to keep them apart.

Onions, Garlic, Leeks, Shallots

Onions, garlic, leeks, and shallots can stunt the growth of plants like pole beans and peas. You also don’t want to plant onions, garlic, leeks, and shallots near each other because if one crop comes down with pests (onion maggots) the rest will also fall victim, like a bad case of head lice.

What vegetables do you avoid planting next to each other and why? What do you consider vegetables that should not be planted together? Tell me in the comments!