Crop profile

Radish crop profile

A quick, simple root crop, ideal for short repeated sowings while the soil stays cool.

Italiano

Starting method

Direct sowing

Direct soil

4 °C

Transplant soil

not available

Night minimum

0 °C

Frost buffer

-15 days

Heat stop

28 °C

Harvest

25–30 days

Indoor lead

not available

Key temperatures

0
5
10
15
20
25
30
35
40 °C

Below 4 °CCold risk: slower growth or cold damage.
4 °CMinimum threshold to start direct sowing: 4 °C.
4–23 °CBest range for growth and production.
23–28 °CPerformance drops and plants move into stress.
Above 28 °CPause transplants: heat stress risk.

Radish cycle

1. Start
Method:
direct sowing
2. Direct sowing
Soil: at least 4 °C
Night minimum: at least 0 °C
3. Growth
Ideal temperatures 4–23 °C
Avoid peaks above 28 °C
4. Harvest
First harvest around:
25–30 days after sowing

How to start

Recommended method: direct sowing.
Prepare the bed when soil and nights are stable.
Sow when soil has reached at least 4 °C and nights stay above 0 °C.

Temperatures to respect

Direct-sowing soil: minimum 4 °C.
Night minimum: minimum 0 °C.
Heat stop: 28 °C.
Suggested frost buffer: -15 days.

Harvest timing

Cycle to first harvest: about 25–30 days.
Harvest gradually as produce reaches maturity.

Seasonal notes

Protect young plants from late frosts and thermal swings.
In summer, avoid water stress and heat peaks above 28 °C.
Steady growth improves development and harvest quality.

FAQ and sources

When should you sow radishes?

Sow radishes directly in cool soil, from about 4 °C, with nights close to 0 °C. They are a spring and late-summer crop: they like cool weather and suffer above 28 °C. Sow small amounts every 10-15 days because they mature together. Do not transplant them: they grow so fast that transplanting slows them and deforms the root. Radishes are perfect fillers between slower crops such as brassicas, young tomatoes, or carrots.

How many days do radishes take to harvest?

Radishes are ready in about 25-30 days, one of the fastest cycles in the garden. Harvest as soon as they reach the expected size for the variety. Radishes left in the ground become spongy, hollow, fibrous, and very hot. Check the base of the plants: when the root shows slightly and has the right diameter, you can pull it. Small and crisp is better than large and hard.

Why do radishes make only leaves and no root?

This happens when plants are too crowded, the soil has too much nitrogen, light is low, or the weather is too hot. Radish must grow fast and without competition. Thin early, leave space between plants, avoid strong fertilizers, and choose cool periods. Sowing too deep can also give irregular roots. If you see lots of tender leaves but tiny roots, harvest the leaves for cooking and sow again in better conditions.

How do you grow sweet, crisp radishes?

You need fast growth and steady water. The soil should stay cool but drained; drought makes radishes hard and hot, while waterlogging can rot them. Sow in spring or late summer, not in peak heat. Thin well and harvest early. A fine mulch helps keep moisture even. For continuous harvests, do not sow a whole packet at once: make frequent mini-sowings, which are much easier to manage.

Can radishes be grown in pots?

Yes. Radish is ideal in pots and shallow boxes. Use a container at least 15 cm deep, fine free-draining compost, and sow directly. Keep the pot in full sun during cool seasons, but in partial shade when heat arrives. Thin without delay: crowded plants do not form round roots. In pots, check water often, because just one dry day during root swelling can reduce quality and flavour.