What Can I Plant with Onions?
Far and away the best onion plant companions are members of the cabbage family, such as:
Broccoli Kale Brussels sprouts Cabbage
This is because onions naturally repel pests that love cabbage family plants, like cabbage loopers, cabbage worms, and cabbage maggots. Onions also naturally deter aphids, Japanese beetles, and rabbits, meaning that good companion plants for onions are any plants that often fall victim to them. Some other particularly good onion plant companions are:
Tomatoes Lettuce Strawberries Peppers
Bad Companion Plants for Onions
While onions are mostly good neighbors across the board, there are a couple of plants that should be kept away from them because of chemical incompatibility and possible flavor contamination. All varieties of peas and beans can be detrimental to onions. The same goes for sage and asparagus. Another bad onion neighbor is actually other onion plants. Onions frequently suffer from onion maggots, which can travel easily from plant to plant when they’re spaced close together. Other onion-like plants, such as garlic, leeks, and shallots, are common targets of onion maggots as well. Avoid planting them near onions so the onion maggots can’t travel easily. Scatter your onions throughout the garden to prevent the spread of onion maggots and to benefit as many other plants as possible with the onions’ presence.
