Growing Radishes: Spring and Fall Crops in a Short Season
Radishes are the quickest reward in the garden, often ready within a month of sowing. They also have a reputation for going wrong: woody, hot, hollow or all leaves and no root. Nearly all of that comes down to timing and spacing.
The short answer
- Sow directly in early spring, 1 cm deep, and again every 2 to 3 weeks until early July.
- Skip July to mid-August. Heat makes radishes bolt.
- Sow a fall crop in late August.
- Thin to about 5 cm apart and harvest at about 3 cm across.
Based on the University of Saskatchewan radish guide.
Sowing
- Sow 1 cm deep and about 2.5 cm apart, in rows 30 cm apart.
- Keep the soil evenly moist until seedlings appear.
- Thin to about 5 cm apart. Crowded radishes make leaves, not roots.
- Full sun is best; part shade is tolerated.
Spring and fall, not summer
Radishes love cool weather. Sow a row every 2 to 3 weeks from early spring, stop for the hottest part of summer, then sow again in late August for a fall crop that grows in the cool weeks before frost. Fall radishes, including larger winter types like daikon, are often the crispest of the year.
Varieties
Recommended for prairie climates by North Dakota State University (via USask): Cherry Belle, French Breakfast, Easter Egg II, Champion, Amethyst, Rover, Roxanne, Red Head, Pretty in Pink and White Icicle. Large daikon and winter radishes need a deep bed rather than a container.
Flea beetles and cabbage moths
Radishes are in the cabbage family, so they attract the same pests. Tiny holes in the leaves mean flea beetles. Cover rows with a lightweight row cover right after sowing, and pull mustard-family weeds nearby.
Water
About 2.5 cm a week. Without enough water, radishes grow small and very hot.
Harvest
- Check the packet for days to maturity, often under a month for spring types.
- Pull at about 3 cm across. Bigger roots turn woody and pungent, and over-mature ones can be hollow.
- Harvest early in the day and refrigerate right away.
- Young leaves are edible too.
Storage
Store near 0°C with high humidity: in a fridge bag with a paper towel, radishes keep a few weeks.
Common radish problems
| Problem | Likely cause | Fix |
|---|---|---|
| All leaves, no root | Crowding, heat, too much nitrogen or too little sun | Thin to 5 cm, sow in spring or fall, full sun |
| Woody or pithy roots | Left in the ground too long | Harvest at about 3 cm across |
| Very hot flavour | Heat and dry soil | Water evenly; grow in cool weather |
| Cracked roots | Uneven watering | Keep soil steadily moist |
| Tunnels in roots | Root maggots | Row cover from sowing; rotate beds |
Beyond the round red radish
- French Breakfast: long, mild, red and white.
- Daikon: large white winter radish. Sow in early August for a fall harvest; it bolts if sown in spring.
- Watermelon radish: green outside, pink inside. Best as a fall crop.
- Black Spanish: a winter radish that stores for months in the fridge.
Radishes as a helper crop
Because they come up in a few days, radishes are useful companions. Sow a few in rows of slow crops such as carrots and parsnips to mark the row and break the soil crust. They are harvested long before the main crop needs the space. Radish seed pods are also edible: if a few plants bolt, pick the green pods while young and crunchy.
Planning next season? Save this guide to your Pinterest board so it is there when you need it.
Gear that helps
- Fine insect netting: A fine mesh barrier against flea beetles, cabbage moths and carrot flies, and it lets rain through.
- Hand seed sower: Helps you sow tiny seeds thinly, so you have less thinning to do later.
- Plant labels: Track varieties and sowing dates, which matters most when you sow in succession.
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Keep reading
- 25 fast-maturing vegetables for a short season
- Growing kale in a cold climate
- Growing beets in a cold climate
Frequently Asked Questions
When should I plant radishes?
Sow in early spring and every 2 to 3 weeks until early July, skip the heat of July to mid-August, then sow a fall crop in late August.
Why are my radishes all leaves and no root?
Usually crowding or heat. Thin radishes to about 5 cm apart and avoid sowing in midsummer.
Why are my radishes too hot?
Dry soil and over-mature roots make radishes pungent. Water about 2.5 cm a week and harvest at about 3 cm across.
What causes holes in radish leaves?
Flea beetles. Cover rows with a lightweight row cover right after sowing.
What is the best radish for fall?
Winter radishes such as daikon, watermelon and Black Spanish do best sown in early August for a fall harvest. They tend to bolt if sown in spring.
Are radish seed pods edible?
Yes. If radishes bolt, the young green seed pods are crunchy and mildly spicy, good raw or stir-fried.
