Radishes are one of those first treats to come from the spring garden. There is nothing like pulling out a colorful root veggie, giving it a little dust and polish, and biting into it before it has a chance to see the kitchen. Did you know you can also enjoy fresh radishes in the fall, as well? In this article, I’m going to explain the difference between spring and winter radishes, and share some tips on growing radishes from seed for a spring crop and for a fall crop. Timing your radish seeding is simply a matter of counting forwards or backwards to frost-free and frost dates.
What is the difference between a spring radish and a winter radish?
There are two types of radishes you will find in a seed catalog: spring varieties and winter varieties. Spring radishes are smaller in size and are meant to be eaten right away. They have a zesty, but mild flavor when pulled fresh from the garden. And germination is quick: Harvesting can happen a mere 30 days after sowing radish seeds. Spring radish varieties include the popular Cherry Belle, a small, bright red radish; French Breakfast radish, which is slender red radish with white tips; the multi-colored Easter Egg Blend; and Royal Purple, which is billed as “great for beginners.” (Learn when to harvest radishes for their peak flavor.)
Spring radishes can be planted in late summer for a fall harvest, too. And while you can’t stick them in a root cellar like their winter radish cousins, they will keep in the refrigerator for several days if you wash and dry them, cut off the leafy greens and long tapered root (if there is one), and store them in a Ziploc or produce bag wrapped in a paper towel.
Winter radishes are usually planted in late summer (usually August into September) and are better suited for winter storage. Starchier and more fibrous, they take a bit longer to grow (about 60 days to maturity), and are usually bigger in size. I have started winter radishes in the spring, but the first hint of hot weather, they’ll bolt. Winter radishes include Daikon, Watermelon, and Black Spanish varieties.
Growing radishes from seed in the early spring
Radishes prefer loose, well-drained soil so the roots can grow downwards. Amend your garden with compost. I usually do this in the fall so my raised beds are ready for those early-spring plantings. Be careful about applying any fertilizers with too much nitrogen as you’ll get lots of leafy greens at the expense of the roots. Radishes thrive when the soil pH is about 6.5 to 7.
You can sow seeds in spring about four to six weeks before your last frost date. They’ll germinate in soil temperatures that are as low as 40°F (4°C), which means they’re among the first seeds you can direct sow. Just make sure the ground isn’t frozen below the soil surface!
Don’t sow radish seeds all at once. Plant your first seeds and then sow some every week until the soil warms up (usually around May), so your whole crop doesn’t mature at the same time.
Sow radish seeds about a half inch to one inch (1 to 2.5 cm) apart and about a half inch deep. If you want to just sprinkle them along a row, you can thin the seedlings after they germinate. Once your plants are about two to three inches (5 to 7.5 cm) tall, thin them so they’re about three inches apart. I just use a pair of herb scissors and snip them at the soil line. Radish leaves are edible, so you can bring your sprouts inside and add them to salads, stir-fries, or sandwiches. (You can trim young leaves (sparingly) from the plants as they grow, as well.)
Caring for radish plants
Water your seeds thoroughly. Radishes are like Goldilocks, they like their soil just right. Too dry and the fruit won’t form, too much moisture and the roots can rot.
Weeding any area that’s home to root vegetables is a good idea as you don’t want anything to compete with your crops. Mulch can help to keep weeds down. It can also help to prevent radish root maggots.
Crop rotation can help mitigate damage if you’ve had issues in the past. You may want to plant your radishes with other members of the cabbage family under a floating row cover. This permeable protector can serve double duty, preventing radish root maggots and their larvae from affecting your radish crop, and other pests, like cabbage moths, from getting to your brassicas, like kale and cauliflower.
Radishes will bolt if the weather gets too warm, producing flowers and setting seed. If your radishes do suddenly start to have buds and flowers, consider leaving some in the ground if you’re not going to eat them. Not only do they attract beneficial insects, like bees, to the garden, they make great companion plants. The radish seed pods are edible, too! Use radishes as a trap crop for flea beetles to keep them away from young eggplants, broccoli, and tomatoes.
In Jessica’s book, Plant Partners, she explains how forage radishes, which produce long taproots, can be used as cover crops to break up compacted soils.
Seeding radishes for a fall crop
Once summer hits, planting radishes is inadvisable because they are a cool weather-loving crop. But, because they are quick to mature, radishes are a great crop for succession planting in late summer and early fall. This is the part where you count based on the days to germination indicated on the seed packet.
Winter radishes take anywhere from 30 to 60 days to become a full-sized vegetable. If you look up your frost date for your region, count backwards to see if the timing is right to plant a vegetable that will have time to mature through the fall. You can also plant spring radishes at this time of year, despite their moniker.
If you are planning on succession planting after you’ve pulled out other crops, make sure you amend your soil with a fresh layer of compost to add nutrients back to the garden. Then you’re all ready for your end-of-season sowing!
Learn how to grow other delicious root vegetables
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