Radishes are a wonderful fast-growing crop to grow in the vegetable garden. Because they take as little as three weeks to mature, I like to tuck radishes in just about anywhere there’s a bit of extra space. By the time the other plants start getting big, the radishes can be harvested, freeing up more room for the slower-growing vegetables. But some vegetables and herbs make better companion plants for radishes than others, so it might be worth planning that intercropping more strategically.
Best Companion Plants for Radishes
The following list contains plants that either provide or receive benefits from radishes — or, in some cases, both. Regardless, you’ll use space more efficiently by planting more than one crop type together.
1. Beans and peas
Beans and peas fix nitrogen in the soil, which radishes need for healthy growth. I like to plant radishes in the same bed as peas in the spring. The peas grow up a trellis, leaving plenty of open horizontal space, and planting a quick crop of radishes there allows me to follow them with a later crop, like winter squash or sweet potatoes.
Because beans mature when the weather gets too hot for radishes, you can sow radishes around the beans in the spring, then harvest the radishes as the bean plants begin leafing out.
Carrot seeds take a long time to germinate — as long as three weeks — giving you plenty of time to forget where you planted them. Radishes, on the other hand, spring up in a matter of days. One of the best ways to clearly mark a row of carrots is to mix some radish seed with the carrot seed. Because the radishes mature first, they will help break up the soil to make way for the carrots, and they can be harvested before the carrots begin to plump up.
Sometimes called French parsley, chervil is a less common herb with a mild flavor somewhere between parsley and tarragon. More importantly for your radishes, it has been known to improve the growth and flavor, and texture of radishes when grown nearby. The mild taste of chervil and the sharp tang of radishes might go well together in a spring salad, too!
The first year I tried to grow cucumbers, striped cucumber beetles all but stripped the vines of foliage and left unsightly marks all over the fruits. But radishes, it turns out, help repel striped cucumber beetles! Cucumbers can grow vertically like pole beans and peas, leaving space below for radishes. They might even provide enough cooling shade to slightly extend your radish season.
The pungent smell of garlic and other alliums deters many insect pests and even rabbits. Garlic also has anti-fungal properties and can help protect crops like radishes from becoming diseased. Just don’t plant it near legumes, as garlic can inhibit the growth of beans and peas.
Another cool-season crop, lettuce makes a great companion for radishes. Leaf lettuce grows at about the same rate as radishes, meaning you can harvest the ingredients for a salad all at once. Because head lettuce takes a bit more time, radishes can fill in the space around it and be harvested just as the heads begin to form and need more room. And if you have a later crop of radishes growing into the summer, lettuce planted nearby will help keep them tender.
The dreaded striped cucumber beetle also likes munching on melon plants. For this reason, you might do well to sow some radish seeds around your melon plants. Of course, melons are summer fruits, so the radishes will ripen well before the vines begin to sprawl.
A showy flowering vine that is also a deliciously peppery addition to salads, nasturtiums are a great flower to add to the vegetable garden. They also make excellent companions, as they repel many insect pests. But if you struggle with aphids, consider planting a separate patch of nasturtiums as a trap crop. The aphids will be attracted to the nasturtiums instead of your radishes and other vegetables, and you can destroy them en masse.
Like carrots, parsnips grow slowly and appreciate loose soil. Radishes sown in the same row as parsnip seeds will help mark the row and break up the soil for the parsnips. In turn, parsnips attract ladybugs, which feed on aphids and other insect pests.
Early spring crops often go well together in the garden and on the plate; spinach and radishes are no exception. Radishes will attract the attention of leaf miners that would otherwise damage a spinach crop. But because we usually grow radishes for their roots (though the greens are edible, too!), the radish crop will likely not be affected.
As mentioned before, radishes can be sown between squash plants in the spring because the radishes will be harvested before the squash vines begin to sprawl (or get bushy, in the case of zucchini and other summer squash). Plus, radishes help deter striped cucumber beetles from munching on squash.
Like squash, tomatoes require plenty of space between plants. But when the plants are still young in the spring, that extra space can be filled with radishes. By the time the tomato plants start getting big, the radishes will be ready to harvest. In the meantime, the dense radish foliage will help prevent weed growth, and radishes also repel two-spotted spider mites.
Worst Companion Plants for Radishes
Radishes get along well with most plants in the vegetable garden, so only a few need to be kept at a distance from them.
Because radishes are brassicas, they share pests and diseases with other cabbage family members. They grow well with other brassicas, but if you struggle with cabbage pests or diseases, you might want to plant different brassicas in separate areas to help prevent such problems from spreading. They should especially not follow one another in crop rotation.
Hyssop is the one plant that should never be planted with radishes. Unfortunately, hyssop inhibits the growth of radishes.
With their short time to maturity, delightful peppery crunch, and many wonderful qualities as a companion plant, radishes are a great cool-season root vegetable to include in the garden. If you’ve been wondering what to tuck into that extra space, wonder no more!
Serena Manickam is a freelance editor and writer and sustainable market gardener in rural Virginia. She holds a BA in environmental science and runs Fairydiddle Farm, a small market garden in which she grows no-spray produce and herbs to sell at a local farmer’s market.