How to Grow Radish: Planting, Growing, Harvesting
Radishes are one of the easiest vegetables for beginner gardeners. They are low-maintenance, resistant to pests and diseases, and ready for harvesting in as little as 3 weeks. And you can easily find a place for them in your backyard, patio, as well as in an indoor vegetable garden.
In this guide, we’ll share our growing tips for how to plant radishes at home, how to care for and harvest radishes, and how to grow radishes so that you have a steady supply throughout the growing season.
Common Radish Varieties
The garden radish, Raphanus sativus, can be found in a wide range of hybrids and cultivars, depending on the shape, size, color, and time of year you can plant and harvest them. The most common radish varieties found in cultivation are spring or summer varieties, and winter varieties.
Spring Radish Varieties
Also known as European radishes, these are the best-known varieties to Western gardeners. Typically planted in spring or summer, they are quick to grow and can be harvested in about a month. They also come in a stunning range of colors, from the classic red, to yellow, purple, black, or white radishes. Popular spring varieties include:
- Cherry Belle: Small, round, and with a mildly sweet aroma, this early spring variety is ready to harvest in just 3 weeks.
- French Breakfast: An elongated radish variety with a noticeable peppery flavor, it also tolerates heat better than other cultivars.
- Plum Purple: As the name suggests, this radish variety has a rich purple color, white flesh, and mild, juicy taste.
Winter Radish Varieties
Winter radishes are a group of several cultivars that are usually harvested later in the growing season, either in the fall or early winter. They take longer to grow, have a milder, less spicy taste than spring or summer radishes, and can also be left in the ground to mature. Here are a few types you can grow:
- Daikon radish: This staple in Asian cuisine has a smooth, white root that’s longer and thicker than the regular garden radishes.
- Watermelon radish: Unlike other varieties, this radish is bright pink on the inside and has green or cream-colored skin.
- Black Spanish radish: This rare variety with white flesh, black skin, and a hot, earthy, bitter flavor slightly resembles horseradish.
When Is the Best Time to Plant Radishes?
Radishes are a cool weather crop. The ideal temperature for growing them is between 50°F and 65°F (10°C and 18°C). For best results, sow seeds in early spring, and then plant a fall crop in late summer. Avoid planting radishes during the hotter months. Radishes don’t grow well in warm weather, and temperatures above 70°F (21°C) can make them turn bitter and go to seed.
For a spring crop, sow spring varieties after the last frost, and continue sowing once every 10 to 14 days until early summer. You can then sow them again in late summer if the weather is not too hot, or in early fall. For winter radish varieties, sow them between late spring and the end of summer. They make a great early winter crop, and can be left in the ground until the first fall frost.
Where Should You Plant Radishes?
Radish plants grow best in full sun. They need at least 6 hours of sunlight per day, especially when young. If they’re growing in too much shade, your radishes will spend all their energy growing big, bushy leaves, and will have thin, slender roots. However, partial shade can be beneficial if you’re growing radishes in hot temperatures, as it can help prevent bolting.
If you have limited space or bad soil, or if you simply want to try something new, radish is also one of the best vegetables for straw bale gardening.
How to Plant and Grow Radishes
Radishes are not too pretentious about the planting site you choose for them. They’re happy growing in the garden as well as in containers, indoors. As long as they receive plenty of sun, cool temperatures, and a moist but well-draining soil mix, they should be more than happy.
Let’s take a closer look at how to grow radishes from seeds.
Prepare the Soil
Radish plants prefer growing in a rich, loamy, sandy, neutral, well drained soil mix. The soil should retain some moisture but should also facilitate drainage, to avoid problems such as root rot. In gardens with heavy, clay soils, you will need to dig up the soil to a depth of a few inches and work in amendments such as aged compost or manure.
Like all root crops, radishes need neutral soil for healthy root development. The easiest and most precise way to check that your garden soil will suit them is to use a soil pH tester. The ideal range should be a pH between 6 and 7. If your soil is slightly acidic, add some lime to neutralize it.
Sow Radishes Seeds
You can start sowing radish seeds after the last spring frost. Soil temperature should be at least 50°F (10°C), otherwise, the seeds will not germinate. Always sow radishes directly in the soil. The seedlings have very delicate roots and don’t respond well to transplanting.
Sow seeds one half inch deep and one inch apart (2.5 cm), in rows about 12 inches apart (30 cm). Or, to make your job easier, sprinkle the seeds on the soil surface and use a rake or your hands to gently pull a thin layer of soil on top. Water the soil immediately after sowing, and make sure that it never dries out completely.
Radish seeds germinate very fast, so expect to see seedlings as early as 4 days after sowing. In cooler weather, the seeds can take around 7 to 10 days to germinate. For a continuous harvest throughout the growing season, sow a new batch of radish seeds once every 10 to 14 days.
How to Thin Radishes
When your radish seedlings have at least one pair of true leaves, it’s time to start thinning them. On average, this is around a week after the seeds sprout. The easiest way to thin radishes is to use a pair of gardening scissors and just snip the leaves at the soil line. Leave about 2 inches (5 cm) between each radish plant, so that their roots have enough space to develop properly.
Water your radishes regularly, preferably once a week, and keep the soil evenly moist. They don’t need a lot of water, but if you allow the soil to dry out, your radish plants will bolt, or develop bitter, pithy roots. Radishes don’t typically need mulching, but in hot climates, a thin layer of mulch applied around the base of the plants will help preserve soil moisture.
Radishes are light feeders. If you’ve used compost or manure to amend the soil before sowing, you don’t need to give them any fertilizers for the first month after the seeds have sprouted. After picking your first harvest, you can lightly dig up the top of the soil, add a bit more compost or fertilizer, and plant your next radish crop.
The best fertilizers for radishes should be rich in potassium and phosphorus, but low in nitrogen. Too much nitrogen can have a negative effect on root growth, causing small, spindly roots, and lush, abundant leaves. For large, juicy, well-developed radish roots, aim for a fertilizer with an N-P-K nutrient ratio of 5-10-10.
Radish plants grow so fast that they rarely suffer from weeds. Even so, keep an eye on your garden beds, and remove any weeds before they get a chance to overcrowd your radishes. To avoid damaging radish roots, pick the weeds by hand, preferably after watering your plants, when the soil is loose and easy to work with.
From seed to harvest, radishes are ready in a matter of weeks. You can harvest spring and summer varieties in as little as 3 weeks after the seeds germinate, or when the roots are about an inch (2.5 cm) in diameter. Winter radishes, such as Daikon, are ready in about 60 days.
Young radishes have a mild flavor and a crisp, juicy texture. If you like your radishes with a bit more spicy flavor, you can leave them in the ground to mature for another week or so — but no more. If you leave radishes in the soil for too long, their roots will become bitter, tough, and pithy, and the plants will soon go to seed. Harvest radishes by grabbing the base of the leaves and pulling the whole plant out of the soil.
Radishes are great raw, in salads or garnishes, but you can also use them in stir fries, or pickle them for later. If you’re growing black radishes, you can even use them to make a natural cough syrup. Radish leaves are edible, with a spicy, mustard-like flavor, and can be blanched, steamed, or turned into pesto.
Common Radish Pests and Diseases
Radishes are a sturdy crop that rarely suffers from any pests or diseases. Common pests include cabbage root maggots, flea beetles, whiteflies, and aphids. You can get rid of them by hosing down the plants and applying a mild insecticidal soap solution. For the root maggot, use row covers or make a cardboard collar around the stems of young plants.
Do not plant radishes in the same spot for two years in a row, or in soil that you used to grow other cruciferous vegetables such as cabbage, broccoli, kale, or cauliflower. This will greatly reduce the risk of clubroot, a fungal disease that has no cure and can easily decimate your entire crop. Ideally, you’ll want to practice crop rotation and avoid planting any Brassicas in the same spot for at least 4 years.
Companion Planting With Radishes
Radishes are great companion plants for slower growing vegetables such as pole beans, cucumbers, or tomatoes. In a garden that doesn’t have too much space, you can sow radishes between rows, and they’ll be ready to harvest before the other plants can grow too tall and shade them. You can also try growing radishes among other root crops such as carrots, turnips, and beets.
In organic gardens, radishes are often used as trap crops. Their leaves have a pungent scent that attracts aphids — great news for your other vegetables, but not so much for the radish plant. Luckily, radishes grow fast enough that a few aphids shouldn’t bother them too much. But if you want to keep them safe, try planting radishes next to aromatic fresh herbs such as dill, sage, or rosemary.
How to Grow Radishes Indoors
Growing radish plants indoors is a quick and easy alternative if you don’t have an outdoor garden space. They grow very well in most homes, and if you can find them a spot that gets plenty of light, you can easily grow them all year round.
Growing Radishes in Pots
The secret to planting radishes indoors is using the right type of pot, and sowing the seeds directly in that pot. Find a long, plastic trough with drainage holes at the bottom. A pot that’s at least 4 inches (10 cm) deep and 12 inches (30 cm) long should do the trick.
Fill your pot with a well-draining, loose soil mix, sprinkle the radish seeds on top, then cover them with a thin layer of soil. Water well, and keep the pot in a sunny room. The seeds will germinate in 3 to 4 days. Thin the plants a week later, then wait until the top of the root is at least an inch wide before you start harvesting radishes. It’s as simple as that.
Radishes truly are the best vegetable for the lazy and impatient gardener. This humble but tasty root crop is remarkably hardy. Provided with the right growing conditions, it pretty much looks after itself, and before you know it, it’s ready for harvesting. So if you have the space and a month to spare, adding radishes to the list of vegetables to grow in your garden is definitely a must.