Companion planting is when you take plants that grow well together to improve the health and growth of one another. Some plants love the company of others, while some can be negatively affected by growing near another plant. I used to find it a little daunting trying to figure out which plants go together and what plants do not. There are different kinds of benefits that certain plants can bring to others, like how Marigolds and Chrysanthemums can deter pests, or how Bee Balm and Butterfly Plants can bring pollinators. 

Plant with basil! Tomatoes were made to go basil. Basil will actually help tomatoes produce greater yields and it repels both flies and mosquitoes. Carrots are also amazing companion plants for tomatoes as carrots help aerate the soil with their harvest, providing better watering to tomatoes.

Marigolds are another great companion if you are looking for a flower element. Other good companions to tomatoes include asparagus, celery, the onion family, lettuce, parsley, and spinach.

Avoid cabbage, beets, peas, fennel, dill, and rosemary. Corn and tomatoes both suffer from the corn earthworm (a nasty little pest, not a song stuck in their heads) Tomatoes and potatoes are both susceptible to blight. Keep these plants separate to prevent the spread of pests or diseases.

Plant with basil is great at repelling pests such as aphids, spider mites, mosquitoes, and flies. 

Additionally, basil improves the pepper’s flavor. Other good companions include onions, spinach, and tomatoes.

Avoid planting near beans, as the vines like to spread around the pepper plant.

Plant with corn! The beans vines will wrap around the corn stock and support and create a symbiotic relationship. This is an example of a “sister crop”. Beans also fix nitrogen in the soil, which is good for corn. Other companions include broccoli, brussels sprouts, cabbage, cucumbers, peas, potatoes, and radishes.

Avoid beets or anything from the onion family. Onions will impede the growth of bean plants.

Plant with marigolds and nasturtiums for pest deterrent and a pop of color. You can also plant with beans, celery, corn, lettuce, dill, peas, and radishes.

Avoid aromatic herbs such as sage, this will stunt the growth of cucumbers.

Plant with carrots, because onions will repel the carrot fly. Onions will also chase away aphids, so plant them near aphid-prone (but onion-friendly) veggies. Other companion plants for onions include beets, cabbage, lettuce, parsnips, tomatoes, and spices like marjoram, savory, and rosemary.

Avoid asparagus, beans, and peas.

Plant with mint! Keeps away the slugs that feed on lettuce leaves. Chives and garlic help repel pests. Beans, beets, broccoli, carrots, corn, peas, radishes, and marigolds also work as good companion plants.

Avoid parsley because it grows as a small yet bushy plant and ends up crowding your lettuce.

Plant with corn! As the squash vines it will wrap around the corn stock and support and create a symbiotic relationship. This is another example of a “sister crop”. Squash also does well planted alongside beans, peas, radishes, dill, and marigolds.

Avoid planting with potatoes. Both potatoes and squash are prone to the common disease blight.

Good to plant with tomato plants that can provide them a bit of shade. Carrots can be heat sensitive. Tomatoes are also known to produce solanine, which is a natural insecticide that targets pests affecting carrot plants. Carrots aerate the soil around the roots of the tomato plants allowing more air and water to reach the roots. Leeks and carrots are also good companion plants. Rosemary, sage, and chives are great herbs to plant with carrots.

Avoid planting near coriander and dill, as they both produce compounds that can harm carrot plants. Parsnips suffer from the same diseases and pests as carrots, so keep them apart to minimize a potential infestation.

Radishes can be planted with cucumbers to attract cucumber beetles away from the cucumber itself. They also do well among carrots because they are harvested before the carrots and they loosen the soil as the carrots start to take off. Onions, beets, cabbage, kale, lettuce, spinach, and squash are also good companions for radishes.

Avoid planting near herb Hyssop.

Corn loves veggies that fix nitrogen in the soil—like green beans. Cornstalks also make a great trellis for vining or trailing plants including beans, cucumbers, peas, pumpkins, and melons (sister crops). Zucchini is a good companion plant when planted among corn as well.

Avoid planting with tomatoes and corn are both affected by corn earworms (a nasty little pest). Plant these two far apart to minimize the spread of these pests while also making sure when rotating your crops you don’t just swap these two out for one another.