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Radishes are a great addition to any garden. They add a tasty crunch to salads and cold dishes, or a mellow sweetness to warm recipes.
And, they’re ideal for beginners and children. Because seeing early results from those quick growing varieties is very encouraging.
Radishes prefer the cool weather of spring and fall. And usually, this is when you plant them.
But, can you plant radishes a little closer to summer or winter? And when is it too late to plant more radishes?
Plant spring radishes no later than a month before daytime highs reach 80℉. For fall plantings, plant radishes no later than 8 weeks before the ground fully freezes. However, these are general estimates. Your location and the type of radish planted can make a difference in the timing.
Let’s take a look at the types of radishes, and when you might want to plant your seeds.
How Late Can You Plant Radishes
Radishes are hardy, cold tolerant vegetables, that prefer to grow in cool weather. You can plant them in hardiness zones 2 – 10.
Most places call for a spring or fall planting, but in zones 7 or higher, you can grow radishes throughout the winter. In these warmer zones, though, don’t plant your radish during the hot summer.
For a general idea of radish planting times, based on hardiness zones, take a look at the chart below.
| ZONE | LOW TEMPERATURES | WHEN TO PLANT |
|---|---|---|
| 2 | -40℉ to -50℉ | March through September |
| 3 & 4 | -20℉ to -40℉ | April through June August |
| 5 & 6 | 0℉ to -20℉ | March through May August |
| 7 & 8 | 20℉ to 0℉ | February through March Late August through September |
| 9 & 10 | 40℉ to 20℉ | Late August through early March |
What Is the Best Time to Plant Radishes
April is usually a good time to start sowing your radish seeds for spring and early summer crops. In most places, the soil has warmed enough for your radish seed to germinate.
Come fall, you should shoot for a September planting. This will give the ground time to mellow out from the heat of summer.
What’s the best temperature for radishes to grow?
According to Clemson University, the optimal temperature to plant radishes is between 50℉ to 65℉.
If you hold off on planting, and the weather becomes too warm, your radishes may end up bolting. Meaning, they’ll go to flower before you have a chance to pick them.
Once that happens they can become woody and develop a strong, very spicy, not-so-pleasant taste.
On the other hand, if radishes are left too long in the ground in fall, and the ground freezes, then your radish may freeze. This can lead to a mushy, inedible radish.
To learn more about growing radishes, take a look here at my how-to guide. You’ll find it helpful.
Spring vs Winter Radishes
Spring Radishes
You can plant spring radishes once the soil is workable. They’ll usually germinate in temperatures of 45 ℉ to 70 ℉.
For spring planting, sow your seeds 4 to 6 weeks before you expect the last spring frost.
If you want to plant later in the season, then look to a late-maturing variety such as the French Breakfast radish. These varieties will tolerate the heat better.
If you’re feeling daring, you can plant radishes through the summer. But, make sure to provide them sun protection and extra water for those hot afternoons.
Because spring radishes are such quick growers, they’re ideal for succession planting. Something you might consider.
With succession planting, you’ll stagger your plantings a week or so apart. By doing so, you’ll have radishes throughout the spring and early summer seasons.
| SPRING RADISH VARIETIES | DAYS TO HARVEST |
|---|---|
| French Breakfast | 21 – 28 days |
| Cherry Belle | 22 days |
| Early Scarlett Globe | 20 – 28 days |
| Crimson Giant | 29 – 30 days |
| Golden Helios | 25 – 35 days |
Winter Radishes
Unlike spring varieties, winter radishes take longer to grow. Roughly, 8 to 10 weeks.
For winter radishes sow your seeds about 4 to 6 weeks before you anticipate the first fall frost.
Radishes can survive a frost, but harvest them before the ground freezes completely.
Winter radishes are larger than their spring cousins. They’ll continue to grow throughout the season, becoming tastier and juicier, rather than woody.
Fun fact – Daikon radish, a winter variety, actually means “big root” in Japanese.
If you want to leave your winter radishes in the ground longer, or throughout the winter, you’ll need to provide protection from the cold weather.
| WINTER RADISH VARIETIES | DAYS TO HARVEST |
|---|---|
| Black Spanish Round | 53 – 70 days |
| Red Meat | 50 – 60 days |
| Alpine Daikon | 55 days |
| China Rose | 58 – 60 days |
| Hilds Blauer | 55 – 60 days |
Final thoughts
- Radishes grow best in cool weather.
- There are spring and winter varieties of radishes.
- Ideally, in the spring plant your radishes no later than 4 weeks before temperatures reach 80 degrees.
- Plant fall radishes within 8 weeks of the ground freezing.
- In warmer zones, radishes can grow throughout the winter.
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