How long do radishes take to grow?

Radishes are one of the fastest-growing crops, maturing in a matter of weeks! Most small varieties mature in about 25 days. Bigger varieties such as Watermelon and Daikon radishes may take longer, about 50-60 days. Factors that may affect how long it takes radishes to grow include light and temperature. While radishes can grow in temperatures as low as 40°F, they may grow more slowly. Because radishes are such a fast-growing crop, we recommend succession planting them to ensure a continuous harvest of radishes and to avoid being overwhelmed with too many to harvest all at once. Read all about succession planting here!

Do radishes need full sun?

While radishes are a cool-season crop and can tolerate part-shade, they do best in full sun, or at least 6 hours of direct sunlight per day. When radishes don’t get enough sun, they focus their energy on developing leaves rather than the main taproot, leaving you with a thin, inedible root. If you live in a cold climate and want to grow radishes in winter, you can supplement with a grow light to make sure they still get enough light.

How to grow radish sprouts?

If you like the taste of radishes, but don’t have enough room in your greenhouse, you can easily grow radish sprouts in your kitchen. Make sure to only use seeds that have been developed for sprouting. Alternatively, you can cut radish sprouts (also called microgreens) when thinning your radishes in the greenhouse for a tasty snack!

Can you grow radishes in the summer?

Yes, you can grow radishes in the summer! However, radishes are prone to bolting in warm climates, so it’s best to grow radishes outdoors and in part-shade during the summer instead of in a greenhouse, unless your greenhouse is climate-controlled. Opt for bolt-resistant varieties to get the most out of your summer radish crop.

How to Grow Radishes in a Greenhouse

Written by Jesse James
Last Updated: April 5, 2024
Greenhouse Gardening, How to Grow Guides

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Radishes grow at lightning speed, with many varieties maturing in just a matter of weeks. They are also incredibly easy to grow, making them ideal for beginner gardeners and experienced growers alike. Radishes make for a great crop to grow in your greenhouse all year long, but especially during the winter or shoulder seasons wherever you have a little extra space.

Radishes are a type of root vegetable belonging to the Brassicaceae family (also known as the cabbage family). This crunchy, spicy root makes for a great treat fresh or added to salads and other dishes. Luckily, growing radishes in the greenhouse is easy to do and requires only minimal care.

Are you ready to add radishes to your greenhouse garden? Keep reading to learn all about growing radishes in a greenhouse, from selecting the right variety to having a steady supply of radishes.

Can you grow radishes in a greenhouse?

Radishes are one of the easiest crops to grow in the garden, but does that translate to the greenhouse, too? You’ll be happy to learn that yes, you can grow radishes in a greenhouse for a longer growing season.

Because radishes are a “cool weather” crop, it’s best to grow them during the cooler seasons from fall to spring. In mild climates, you can even grow radishes in a greenhouse or cold frame without a heater in winter. For colder climates, you may have to provide minimal heating.

Grow radishes alongside other cool-weather growing crops such as spinach, lettuce, and leeks. Because they take up very little room and are fast-growing, you can even grow these root vegetables alongside slower-to-germinate crops such as carrots, parsley, and broccoli. By the time the bigger crops start filling out, you’ll be able to harvest your radishes.

Radishes with root in bunch with text: Beginner's Guide Growing Radishes in a Greenhouse

Popular radish varieties to grow in a greenhouse

There are many different types of radishes (Raphanus sativus) that you can grow in a greenhouse. While the radishes you might find in the grocery store tend to be small, round, and red, you can get radishes in all shapes, sizes, and color – even black!

When choosing what variety of radishes to grow, appearance isn’t the only thing to consider. Some radishes have a spicy flavor and others are well-suited for heavy soils. If your greenhouse is prone to temperature swings on warm days, bolt-resistant varieties are your best bet.

Here are our top picks for radishes to grow in a greenhouse:

French Breakfast Radish

If you’re looking for a quick-growing, spicy radish, the French Breakfast Radish is a classic choice. French Breakfast Radishes are known for their elongated roots that are pink and white in color.

Days to mature: 26

Watermelon Radish

Watermelon Radishes get their name from their watermelon-like appearance: while the outside is white, the inside is bright pink. The round roots are slightly larger than typical radishes (2-3 inches) and they also store particularly well.

Days to mature: 60

Cherry Belle Radish

Cherry Belle Radishes have the classic radish appearance: round and red with juicy white flesh. They are on the smaller side (typically no bigger than 1 inch), but pack a sharp punch when it comes to flavor. The green tops can also be used fresh or sautéed.

Days to mature: 25

Daikon Radish

Daikon Radishes are a Japanese variety that are much larger than any other radish, growing as long as 12-14 inches and weighing up to 6 pounds! They are particularly well-suited for growing in a greenhouse during the winter. Due to their size, they can penetrate even the heaviest of soils, so you can grow them as a way to naturally break up your soil. Daikon radishes are best enjoyed added to stews or pickled, though they can be sliced and eaten fresh, too.

Days to mature: 50

Quick overview of growing radishes in a greenhouse

Type: Cool-season crop
Time from seed to harvest: 22-70 days
Germination temp: 40°F
Time until first emergence: 7-10 days
Best temp to grow: 50-70°F
Height: 6-8 in
Spread: 4-8 in
Grow from seed: 1/4-1/2 inches deep, 1-2 inches apart in rows
Companions: Chervil, marigold, brassicas, dill, parsnip, pole beans, mint, peas, oregano, borage, nasturtiums, rosemary, and eggplant
Keep away from: Corn, kohlrabi, sunflower, hyssop, turnips, melons, pumpkin, and potatoes

How to plant radishes in a greenhouse

Because radishes grow so fast, and because they are root crops, most people choose to grow them directly from seed. However, you can also sow r