Radishes are a favorite for beginner gardeners—and for good reason. These crunchy veggies grow fast, with some types ready to harvest in just 30 days! But if you want your radishes to grow strong and healthy, it’s important to be careful about which plants you grow nearby. Some plants can block sunlight, steal important nutrients, or even spread diseases that harm radishes. Here’s a list of eight plants that expert gardeners say are best planted far away from your radishes.
1. Corn: Too Tall for Radish Friends
Corn (Zea mays) is a sweet and satisfying summer crop, but it’s not the best neighbor for radishes. Corn grows tall—really tall—and that means it throws a lot of shade. Radishes love full sun, so too much shade from corn can lead to small, underdeveloped roots. If you want to enjoy both, just be sure to give each its own sunny spot in the garden.
2. Fennel: A Fussy Plant with a Bad Attitude
Fennel (Foeniculum vulgare) smells amazing and adds flavor to many dishes. But in the garden, fennel doesn’t play well with others. It releases chemicals into the soil that can slow down or even stop nearby plants from growing well—including radishes. This makes fennel a “solo” plant. If you’re growing it, give it space all by itself.
3. Potatoes: Underground Trouble
Potatoes (Solanum tuberosum) may look calm above the soil, but below the surface, they’re spreading out in every direction. Their strong roots can get in the way of radishes, especially bigger types like daikon. Also, potatoes need a different kind of soil than radishes. These differences mean the two shouldn’t share a bed—literally!
4. Hyssop: Pretty but Problematic
Hyssop (Hyssopus officinalis) is a beautiful herb that draws bees and butterflies, making it perfect for pollinator gardens. But when it comes to vegetables, especially radishes, hyssop isn’t so friendly. Garden designer Jane Gates says hyssop gives off chemicals that can slow down or harm other plants. You can still enjoy its flowers—just plant them in another part of the yard.
5. Broccoli: Too Close in the Family
Broccoli (Brassica oleracea var. italica) and radishes are part of the same plant family, Brassicaceae. When they grow near each other, they fight over the same nutrients in the soil. Broccoli can also release chemicals into the dirt that might make your radishes struggle. To keep both veggies happy, give them their own spaces in the garden.
6. Turnips: Cousins Who Share Everything (Even Pests!)
Turnips (Brassica rapa subsp. rapa) are also part of the brassica family. That means they’re not just nutrient competitors—they also share pests and diseases with radishes. Horticulture teacher Ken Johnson says that while you can plant them near each other, you’ll need to keep an eye out for bugs and other problems. Rotating where you grow each crop every year can help reduce these risks.
7. Sunflowers: Beautiful but Shady
Sunflowers (Helianthus spp.) are tall and cheerful additions to any garden. But those bright blooms come with a downside—the plants can get very tall and block sunlight from smaller crops like radishes. Radishes love the sun, so they won’t do well in sunflower shade. Try planting sunflowers along the back of your garden so they don’t block out the light for shorter veggies.
8. Kohlrabi: The Space Hog
Kohlrabi (Brassica oleracea var. gongylodes) might be one of the most unusual-looking veggies, but it’s closely related to radishes. Like turnips and broccoli, kohlrabi competes with radishes for space, nutrients, and water. If your soil isn’t super rich, one crop might grow better than the other. A soil test can help you figure out what your garden needs to keep everyone happy.
