Radishes are one of the fastest crops you can grow. Most spring radishes are ready to pick 3 to 4 weeks after you sow them. They are a great first crop for kids and new gardeners.
The keys to good radishes are cool weather, room to grow, and steady water. Get those right, and you get crisp, mild roots. Get them wrong, and you get leaves with no roots, or roots that are woody and hot.
When to plant radishes
Spring
Sow radishes outdoors as soon as the soil can be worked. That is about 4 to 6 weeks before your last spring frost. Radish seed sprouts in cool soil, often in 3 to 10 days.
Sow a short row every 10 to 14 days until late spring. That gives you a steady supply instead of one big harvest.
Stop sowing spring radishes once the weather turns hot. Heat and long days make radishes bolt, turn woody, and taste hot.
Fall
Sow radishes again in late summer, about 4 to 6 weeks before your first fall frost. Cool fall weather gives you some of the best radishes of the year.
Late summer is also the time to sow winter radishes like daikon and watermelon radish. They take longer to grow, often 50 to 60 days or more.
Where to plant radishes
Radishes grow best in full sun. In light shade, they grow more leaves and smaller roots.
They need loose soil with no rocks or clods. Work in some compost before you sow. Avoid heavy doses of nitrogen fertilizer, since too much nitrogen gives you big leaves and small roots.
Radishes grow well in containers too. Use a pot at least 6 inches (15 cm) deep. Long varieties need a deeper pot.
How to plant radish seeds
- Loosen the soil and rake it smooth.
- Sow seeds 1/2 inch (1 cm) deep and about 1 inch (2.5 cm) apart.
- Space rows 12 inches (30 cm) apart.
- Water and keep the soil moist until seedlings come up.
- Thin seedlings to 2 inches (5 cm) apart for round radishes. Give long radishes like daikon 4 to 6 inches (10 to 15 cm).
Thinning is the step most people skip. Crowded radishes do not form roots. Snip the extra seedlings at soil level with scissors so you do not disturb the ones you keep. The thinnings are good in a salad.
Watering
Radishes need steady moisture. Give them about 1 inch (2.5 cm) of water a week, more in warm, dry weather.
Uneven watering causes most radish problems. Dry soil makes radishes hot and woody. A heavy soak after a dry spell can make them crack.
Best radish varieties
| Variety | Type | Notes |
|---|---|---|
| ‘Cherry Belle’ | Round, red | Classic salad radish, fast |
| ‘French Breakfast’ | Oblong, red with a white tip | Mild and crisp |
| ‘Easter Egg’ | Round, mixed colors | Red, pink, purple, and white in one packet |
| ‘White Icicle’ | Long, white | Mild, good for spring |
| Daikon | Long, white winter radish | Sow in late summer |
| Watermelon radish | Round winter radish | Green outside, pink inside, sow in late summer |
How to harvest radishes
Start checking once the tops of the roots push up out of the soil. Brush the soil back and look at the size. Most round radishes are ready at about 1 inch (2.5 cm) across.
Pull one and taste it. If it is good, pull the rest of that row within a week or so. Radishes left in the ground too long turn pithy, hollow, and hot.
Twist or cut off the tops, leaving a short stub. Store the roots in a bag in the fridge for up to two weeks.
Radish greens are edible too. Cook them like spinach. If a few plants bolt, the young green seed pods are crisp and spicy, and good raw or in a stir-fry.
Common radish problems
| Problem | Likely cause | Fix |
|---|---|---|
| All leaves, no roots | Crowding, shade, heat, or too much nitrogen | Thin to 2 inches apart, grow in full sun, sow in cool weather |
| Hot, spicy flavor | Heat or dry soil | Water every week and sow earlier or later in the year |
| Woody or pithy roots | Picked too late or grown in heat | Harvest on time and sow small batches |
| Cracked roots | Uneven watering | Keep the soil moist at all times |
| Tiny holes in leaves | Flea beetles | Cover with row cover after sowing |
| Tunnels in roots | Root maggots | Use row cover and rotate where you plant |
Radishes as row markers
Radishes come up in days, while carrots and parsnips can take two or three weeks. Sow a few radish seeds in the same row as carrots. The radishes mark the row and break up the soil crust. You pull them before the carrots need the space. Here is more on how to grow carrots.
More cool-season crops
Radishes grow at the same time as these crops:
Seed companies I like
These are the seed companies I order from for my own garden.
- Botanical Interests: beautiful packets with growing notes printed inside
- High Mowing Organic Seeds: certified organic, grown in Vermont
- True Leaf Market: big selection of hybrids, microgreens, and cover crops
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