When to Harvest Radishes

The radish plant is a reliable member of the vegetable garden. Quick and easy to grow, with a little luck and effort you can be harvesting fresh radishes within 4 weeks of sowing the seeds. But when is the best time to harvest radishes?

If you are new to gardening it can be difficult to know exactly when to harvest radishes or other produce. Pull your vegetables too soon and they will be small and disappointing. Wait too long and the vegetables may spoil and start to split.

If you struggle to know when to harvest radishes, this guide will explain exactly what you should be looking out for. As well as explaining when to harvest radishes, we will also provide you with some general care and maintenance tips to help you grow a bumper radish crop.

1 When to harvest radishes
Knowing when to harvest radishes enables you to make the most of this easy to grow crop. 

Different Radish Varieties

Before I explain when to harvest radishes, I will briefly explain the differences between radish varieties. This is important because each variety has its own appearance, growing needs and maturity time. For example, spring varieties tend to mature far quicker than winter types.

A member of the cruciferous vegetable family, the radish plant typically produces small, globe shaped roots. However, you can also grow varieties with longer radish roots. Usually red in color, some varieties produce white, purple, pink, yellow and even black roots. They can also be hot or mild in flavor. The longer you allow your radish to remain and mature in the ground the warmer its flavor. Black radish varieties, such as the Spanish radish tend to be the hottest.

Generally small, round radish types are easy to grow and quick to mature. Larger varieties can take a little longer to mature and may require more attention.

Typically radish plants are divided by their planting date.

Spring varieties are quick to grow and mature. Cool weather loving, these varieties struggle and may bolt, or go to seed, in warm temperatures. Common varieties include:

  • Early Scarlet Globe produces round red roots that mature in 22 days,
  • Easter Egg produces oval shaped roots in a range of colors, these typically mature within 25 days.
  • Cherry Belle is a round and red radish that matures in 22 days.

Summer and Fall radish plants are more heat tolerant than spring varieties but can still struggle during prolonged periods of hot weather. Popular summer and fall radish varieties include:

  • Scarlet Globe AGM produces a bright red radish with white flesh. Known for its mild flavor, Scarlet Globe matures within 25 days.
  • Icicle is a heat tolerant variety. Maturing within 25 days, it produces long, slender white radishes.
  • French Breakfast produces oblong shaped roots. Maturing within 28 days it is a good choice for pots and planters.

2 Variety of shapes and colors
While they come in a range of shapes and colors, when it comes to knowing when to harvest radishes, the same advice applies, whatever variety you choose to grow. 

Winter radish varieties take longer to mature than other types. Typically planted in late summer, they should be harvested before the deep winter frosts set in. Lasting longer than spring varieties, winter radish plants can be left in the ground until you are ready to use them. Reliable winter types include:

  • Daikon, a long, white variety with a mild flavor. It matures in 60 days
  • China Rose is an attractive radish with red skin and white flesh. It typically matures in 52 days

As well as the roots, the pods and the tops of radish plants, sometimes called greens, are also edible.

How to Sow Radish Seeds

Before you start working out when to harvest radishes, you must first sow the seeds.

Radish seeds are best sown directly in their final growing position. Spring and summer varieties are best planted on a cool day when the soil is dry. If you are planting late in the summer or early in the spring, make sure there is enough room around the plants to place a cold frame or a Agribon Frost Blanket over growing the plants. This helps to protect them from any unexpected deep frosts.

Growing radish plants don’t require much room. Quick to germinate and mature they can be planted amongst other crops in the vegetable garden. Sowing a few radish seeds as you harvest other crops is a great way to fill any gaps in your vegetable beds. A radish crop is also a good way to loosen or cultivate soil before sowing slower vegetables like carrots.

Sow radish seeds a quarter to half an inch deep. Space the seeds at least 2 inches apart. Following germination, growing seedlings can be further thinned out when they reach 2 inches in height. Each radish variety has its own spacing needs, check the seed packet for the precise information. If you find radish seeds difficult to handle, a seed dispenser, such as the Coolrunner Seed Dispenser, enables you to easily set out seeds of all sizes to the correct spacing.

3 Thin seedlings out
Following germination, thin the seedlings out as soon as possible. 

Radish seeds grow best in full sun positions. In cool weather zones, planting in full sun speeds up growth, enabling you to harvest radishes even sooner. In warmer planting zones sowing in a partial shade position helps to keep the crops cooler for longer.

The soil should be rich and loose or well draining. A slightly acidic or neutral soil is also preferred but not necessary. Just avoid planting in extremes. If you don’t know the makeup of your soil, a soil test kit is an easy way to find out what amendments you need to make before planting. Work the soil over before sowing so that it is not overly compacted. Like other root crops, radish plants struggle in compacted or rocky soil.

If you are growing spring maturing varieties, sow the seeds as soon as the soil is workable and the last frost date has passed. For an even earlier crop, sow seeds in pots in February and protect with cloches.

For a continual harvest succession sow new seeds every 10 to 14 days. Continue to sow the seeds until the weather gets too warm.

Growing Radish Plants in Pots

You can also sow and grow radish seeds in pots. Regular sized radish plants, such as Cherry Belle and Easter Egg can be planted in pots at least 6 inches deep. Space around 2 inches apart.

Larger varieties, such as Daikon require pots that are at least 12 inches deep. These should be spaced 4 inches apart. Typically a 12 inch wide pot will hold 6 or 7 typical sized radish plants or 4 large varieties.

Fill the pots with fresh potting soil and sow the seeds 4 inches deep. If you can’t correctly space the seeds when sowing, remember to thin them out after germination.

Caring for Radish Plants

Once sown and germinated, these plants require just a little regular care before it is time to start to harvest radishes.

If it doesn’t rain, apply around 1 inch of water a week. During dry spells growing plants require more frequent watering. When watering your radish plants, use a hose to soak the soil so that the roots are fully drenched.

As the temperatures warm, keeping the soil evenly moist and mulched. This helps to keep plants cool and also prevents the roots from splitting.

4 Plant in favorable conditions
Plant in well draining soil and with just a little light, warmth and water these crops soon begin to flourish. 

Radish plants stop growing when temperature warms. Exposure to warm weather can also trigger bolting. This means that the root stops developing and flowers emerge. If this is allowed to happen radish roots can become tough or woody. They can also develop hollow centers.

Quick growing crops, there is no need to fertilize radish plants as long as soil is rich. This is not usually a problem if you are planting alongside other vegetables. Remember to amend poor soil before planting.

Common Pests and Problems

Remember to protect the developing foliage from slugs and snails. If slugs are a particular problem, this article is full of effective, easy to adopt methods to protect your plants.

Brassica downy mildew can cause foliage to yellow. With a clean garden scissors, cut away any yellowing foliage as soon as you notice it. Adopting a simple crop rotation system, and avoiding planting two brassica crops straight after each other in the same bit of soil, helps to prevent the issue.

Cabbage root maggots are common in northern areas. If present in the soil, the little pests can tunnel into the radish roots. Cutworms can also feed on radishes. Meanwhile flea beetles may target the foliage but usually leave the bulb intact. Regularly check the foliage for signs of infestation or disease. Growing crops under Plant Covers helps to protect them from most common types of pests.

When to Harvest Radishes

To know when to harvest radishes it is important that you check the size of the root or bulb frequently. Don’t be afraid to move the soil a little so that you can properly feel the size of the tops. The aim is to harvest radishes before they start to decline.

5 Pay attention to the size
The key to knowing when to harvest radishes is to pay attention to their size. 

Spring varieties are typically quick to mature. You can harvest radishes sown in the spring usually within 4 weeks of the seeds germinating.

As the root develops, the top portion tends to poke through the top of the soil. When the top of the root is 1 inch wide you can start to harvest radishes. If you are unsure, place a quarter on the soil next to the radish. Harvest radishes when the exposed top section is roughly the same size as the coin.

Aim to lift your spring and summer varieties before the weather warms. Radish roots allowed to sit in warm weather for a prolonged period can split and spoil.

Winter radish types take longer to mature. Some varieties can take up to 3 months to fully mature. Like spring varieties, when the crop reaches the desired size it is ready to pull. If you are unsure what size your mature radish should be, consult the seed packet.

Don’t be afraid to move the soil or pull one plant up as a test plant to check their size and development.

When you are ready to harvest radishes, simply loosen the soil around the plant and then pull or lift it from the ground. Don’t allow mature roots to sit in the ground for too long. Aim to harvest winter varieties before the ground freezes.

After you harvest your radishes it is important that you know how to correctly store them. This increases their lifespan, enabling you to get the most from your crops.

To store the crop, cut away the leaves or green tops. These should be stored separately, away from the bulbs. Don’t allow the leaves to remain in place. They can take nutrients and moisture from the bulb, reducing their lifespan.

Leaves or green tops can be kept for 3 to 5 days. They can be used as salad greens, soup garnishes or in sandwiches.

Spring or globe shaped radishes can be stored in a refrigerator in a sealed container for a week. Winter radish varieties last for around 2 weeks in the refrigerator or up to 4 months in cold storage.

6 Clean roots after harvest
Following the harvest, clean your roots and use them as soon as possible.

Easy to grow and relatively low maintenance, the radish plant is a reliable and versatile member of the vegetable garden. A good catch crop because it is quick to mature, happily filling space between rows of slower growing crops such as potatoes and peas. A couple of radish plants can also be a useful row marker for slow germinating crops like onions and parsnips. Finally, larger varieties, such as Daikon, can also be planted to help improve heavy, clay soils.

Happily growing for large parts of the year, radish plants are a great option if you are aiming to grow your own food throughout the year. Knowing when to harvest radishes is, like the rest of the process, pleasingly easy.

When to harvest radishes 1 When to harvest radishes 2