Not All Plants Make Good Neighbors
By: Patty Cressman
Grayson County Master Gardener
Not all plants play well together, and some plants make terrible neighbors to one another. There are plants that make great companions and grow well together, but there are plants that should not be planted near each other.
Potatoes make terrible neighbors to tomatoes, squash, peppers, eggplant, sunflowers, turnips, melons, and cucumbers. In fact, potatoes need to be planted together away from other crops.
Melons and squash are prone to catch the same diseases and attract the same pests. Therefore, they should not be planted together.
Sunflowers are great at attracting pollinators. However, they need to be at least 12 inches away from the nearest plant as their roots emit a chemical that make it difficult for other plants to grow. Be aware the seed heads that drop emit a chemical that can kill other plants.
Avoid planting radishes near broccoli, cauliflower, cabbage, kohlrabi, potatoes, turnips, and grapes.
Corn and tomatoes should not be planted together. The tall stalks of corn can stunt the growth of tomatoes. Also, corn and tomatoes are susceptible to similar fungal infections as well as the destructive corn earworm.
Cauliflower and broccoli are very similar plants and should not be planted together because they are prone to the same diseases and pests. Also avoid planting cauliflower and broccoli next to squash, strawberries, tomatoes, and peppers.
Avoid planting onions near any other plants in the allium family including garlic, leeks, and shallots. These plants will stunt the growth of each other and attract the same pests and diseases.
Marigolds are helpful in vegetable gardens but are not good neighbors to beans and peas.
Cabbage and cauliflower should not be neighbors. When planted side by side they are prone to a fungal disease, club root. This disease causes the roots to not be able to ingest water. As a result, the plant will wither and die.
Lettuce gets along well with most plants, but not kale and cauliflower. Lettuce does not grow well with the allium family (garlic, onions, and shallots). Lettuce competes with allium family for the same nutrients. Also, the garlic and onion plants produce chemicals that can hinder the growth of lettuce.
Do not plant asparagus too close to any other fruits or vegetables as this may stunt the growth of the plant. Specifically, do not plant asparagus too close to onions, garlic, or potatoes as they all need a lot of soil space.
Kale and basil do not cohabitate well together. But kale can grow with sage, rosemary, or thyme.
Strawberries need a home of their own. Cabbage, kale, broccoli, and cauliflower attract pests that can inhibit the growth of the strawberry plants. Since strawberries return each year, they should be planted by themselves.
Garlic is not a good companion to beans, peas, or other legumes. These plants will not thrive near garlic and the vegetables may have a strange flavor. Beans do not grow well with the allium family such as onions, chives, and leeks. Also, do not plant beans near the cabbage family (cauliflower, kale, and broccoli).
Basil and cucumbers should not be planted near each other. Furthermore, cucumbers should not be planted near sage, rosemary, and marjoram. The strong flavor of the herbs affects the flavor of the cucumbers.
Pumpkins should not be planted near potatoes. The pumpkin plants grow low to the ground and provides too much mulch for the potato plant.
Peppers should not be grown near tomatoes, potatoes, or eggplant. Also, pepper plants should not be planted near kohlrabi and fennel.
Avoid planting alfalfa in your garden. It has a form of allelopathy that interferes with the germination of other plants including itself.
A black walnut tree is detrimental to a garden as it releases a chemical that can inhibit the germination, growth, survival, and reproduction of other plants. The tree is particularly harmful to corn, eggplant, and tomato plants.
Carrots should not be planted near any plant it is closely related to including fennel, dill, and parsnips as they attract the same pests.
Spinach should not be planted near potatoes as they compete for nutrients and water. Also, potatoes tend to grow tall and block sunlight from the spinach.
Eggplant should not be grown near tomatoes, potatoes, peppers, and other plants in the nightshade family.
Rosemary should not be grown near cucumbers as it releases a chemical that will inhibit the growth of the cucumber.