How to Plant, Grow, and Care For Radishes
Are you thinking of adding radishes to your garden, but aren't sure what to expect? Radishes are an excellent vegetable to grow, but it's not without some certain nuances. It's important to understand that these plants are different than many others, and require specific types of care to flourish. Organic gardening expert Logan Hailey examines everything you can expect when planting, growing, and caring for radish in your garden.
Radishes are one of the easiest vegetables to grow for beginner gardeners. They are quick to mature, low-maintenance, and easy to germinate! They also have diverse uses in the kitchen and can be grown in almost any season.
Plus, they add an exciting colorful crunch to spring salads, summer slaws, and winter roasts. Just take your pick: round, red, purple, daikon, French breakfast, or watermelon? There are dozens of unique varieties of radishes far beyond what you typically find on grocery store shelves.
These peppery roots are the most laid-back vegetables in the garden. They aren’t finicky nor are they super needy. They are perfect for impatient gardeners or those with small spaces. With just a few simple steps, you’ll have the best harvest in the neighborhood. Let’s dig in!
Plant Type Annual or Biennial
Plant Family Brassicaceae
Plant Species Raphanus sativus
Plant Genus Raphanus
Hardiness Zone USDA 2-10
Season All Seasons
Sun Exposure Full Sun
Watering Needs Moderate
Maturity Date 21-50 Days
Plant With Garden Plants, Herbs
Don’t Plant With Fennel
Soil Type Well-Draining Loam
Plant Spacing 1-3 inches
Fertility Needs Light to Moderate
Plant Height 6-8 Inches
Pests Flea Beetles, Cut Worms
The Easiest Vegetable for Beginners
I clearly remember the very first vegetable I successfully grew: a radish, of course! There I was, leaping around the garden with a fistful of red soil-covered roots. I didn’t care that they were the easiest, fastest crop to grow! They were the quick reward that gave me hope through my inevitable future garden failures.
You could practically close your eyes and toss some seeds into the soil and they would yield. This tasty root veggie is as beginner-friendly as vegetables get.
- Hardy in most weather conditions (except heat)
- Near instant gratification- ready to harvest in as little as 3 weeks
- Excellent for spring or fall
- Low maintenance
- Light feeders
- Easy to store
- Versatile in the kitchen
- Seeds have a notoriously long shelf life
- 100% edible (leaves, stems, roots, flowers)
Radishes are so easy to grow because they are closely related to wild field radishes. Plant breeders have developed many shapes, sizes, and flavors for every palate or preference. There are spicy peppery radishes like horseradish or black Spanish radish. There are milder crisp salad radishes like the classic red round or French breakfast. And there are fun fall/winter storage radishes like watermelon and purple daikon.
Regardless of which varieties you choose, they all grow very similarly and can be grown even without much of a “green thumb.” They have been cultivated for thousands of years. Originating in South Asia, they were some of the earliest agricultural crops and one of the first vegetables brought to America.
Most of us grow gardens to help us live healthier, more vibrant lives! In this day and age, we need as many vegetables as we can get and these veggies definitely fit the bill for easy-to-grow nutrition!
Radishes are nutrient-dense veggies with over five times more potassium than a banana! They contain cancer-fighting compounds and heart-healthy anthocyanins. In raw form, they are also an excellent source of vitamin C and fiber.
Radish greens are tasty and nutritious, too. The greens actually have nearly six times the vitamin C content of the roots. You basically get an extra bunch of arugula with every root! Use their greens in stir-fries, sautees, and soups for a slightly mustardy or arugula-like kick. Certain varieties have spicier greens than others, so give them a nibble to determine your preferences.
Propagation and Planting
Radishes are best directly sown in the garden. They are ready to eat in under a month, making them perfect for the impatient growers among us.
Succession planting is used by farmers and advanced gardeners to maintain a continuous supply of vegetables. It’s basically just staggered planting dates. At any given time, you could have baby radishes that have just germinated, “teenage” radishes that have a couple more weeks, and a batch of full-grown radishes you are harvesting from.
To succession plant in your garden, direct seed a new variety every two weeks. You can also plant a quick-maturing (21 days) variety at the same time as a longer-season (50 days) variety to get a staggered harvest.
When to Plant
They can be sown at any time in the season, beginning in early spring. The best time to start seeding radishes in outdoor gardens is 4-6 weeks before the estimated last frost date of your region. Use row cover to protect early plantings. You can begin sowing in greenhouses or low tunnels even sooner.
They do best in the cooler spring and fall months, however, we will discuss a few heat-tolerant summer varieties below. Late summer varieties are excellent for fall harvests and storage throughout the winter.
If you plant in late fall (4-6 weeks before the first frost), established plants can survive temperatures down to around 26° F. They can grow in USDA zones 2-10, however they can only grow through winter in zones 7 or warmer. Very cold temperatures damage greens, but roots tend to hold in the ground quite well as long as hungry winter rodents don’t get to them.
How to Prepare Soil for Planting
To prepare for planting, clear and rake the soil surface. Add a 1-2” layer of compost if desired. Radishes are shallow-rooted and not super finicky, but they do enjoy a nice loamy soil and consistent moisture.
Be sure that the soil is not compacted or too hard for the taproots to grow downward. Compaction, water stress, and heat stress will make them spicier and less tender. To keep them mild and sweet, they are best grown in cool friable soils.
How to Direct Seed
Radishes should always be directly seeded into your garden. Plant seeds ½” deep and gently cover them with a thin layer of soil. Water thoroughly at the time of seeding and keep moist for 3-10 days until they germinate.
They germinate best at the optimal soil temperatures of 60 to 70° but will tolerate soil temperatures as low as 50°. Use a soil thermometer to check soil temperatures before planting.
Most plants should be seeded about ¾” to 1” apart and thinned to 1” apart once germinated. Plant rows 6” to 1’ apart.
Larger varieties like ‘Red Meat’, ‘Nero Tondo’, and ‘Green Luobo’ should be thinned to 3-6” apart. A simple way to approach spacing is by imagining how big these radishes will be at harvest and give them that amount of space.
If you plant them too close together, the stress of competition can cause premature bolting. When in doubt, thin thin thin!
Companion planting is an old-time garden technique that improves the growth of multiple crops by interplanting them together. It also adds biodiversity to the garden and potentially helps repel pests like pill bugs, or attract beneficial insects like butterflies.
Because they don’t have huge root zones, radishes can be tucked in empty spaces between almost any plant all around the garden. They will compete with weeds and maximize space without competing with your other crops for moisture or nutrients.
Radishes will thrive in a little bit of shade beneath taller-growing plants and will be ready to harvest faster than long-season crops, just be sure they have enough sunlight to not get “leggy.”
They especially like being planted with:
- Other Brassicas (broccoli, turnips, cauliflower, cabbage, etc.)
- Pole Beans
- Mint and hyssop
Varieties of Radish
Plant breeders are developing new organic crop varieties all the time. Just like breeding for a best-in-show Golden Retriever, plant breeders can select desirable radish traits to perpetuate in new strains. Some of the most important traits to look for are seasonality, flavor, color, yield, bolt resistance, and vigor.
There are three main types of radish based on the season they are planted:
- Early Varieties
- Late/Fall Varieties
Early radish varieties are bred to be planted in the cool weather of spring. They are cold-hardy and quick-growing.
‘Rover’ Round Red
This extra early radish is a vigorous F1 hybrid with only 21 days to maturity. It can be planted throughout spring and into early summer because it maintains attractive round roots even under some heat stress. The roots are smooth and a dark beautiful red color with a classic crisp, white interior. ‘Rover’ is adapted to nearly every growing zone and holds well in the garden if you need to delay harvest.
‘Easter Egg II’ Multicolor Mix
Perfect for spring, these seeds make for gorgeous radish bunches of red, pink, purple, and yellow-white. They mature at a staggered rate over the course of 25-30 days and stay mild even when they get a bit oversized. They also resist pithiness.
‘French Breakfast’ Radish
The classic elongated pink-and-white French Breakfast radishes are a lovely spring treat. They are unique and fast-growing (only 21 days) for spring. This variety can handle the cold and puts on a nice large canopy to protect roots from sun-scald. Because they have long straight roots, they can be planted closer together (½” to ¾” spacing). For best yields and to reduce splitting, don’t irrigate unless necessary.
Mid-Season (Heat Tolerant) Radishes
Mid-season radishes are the trickiest to grow because they don’t like heat. They tend to bolt (go to seed) in hot weather, which renders the roots far too spicy, woody, and inedible. Many seed companies have developed bolt-resistant varieties for growing in mild summer weather. Shade cloth and growing in cooler areas of the garden can help extend the season even farther into summer.
‘Sora’ Round Red
This organic radish matures in just 22 days and maintains round roots that resist pithiness even in hot weather. ‘Sora’ is versatile for spring, summer, or fall crops, but it especially shines when other varieties have bolted in the heat. This is an open-pollinated certified organic variety. It is best that you harvest them small, beginning when roots reach the size of a large marble and continuing throughout 1-2 weeks before roots are any larger than golf balls.
‘Nero Tondo’ Black Spanish
This is the most uniform and bolt-resistant black radish I have found! The unique black skin and crisp, white flesh are spicy and hot, per the Spanish tradition. Thanks to great bolt resistance, ‘Nero Tondo’ can be sown mid-spring through the fall and stores great in the ground. Keep in mind it will get spicier in hot weather.
Late Radish Varieties
Autumn radishes tend to be sown at the end of summer. They have the longest days to maturity and tend to put on more mass. These roots can hold in the ground after the first few frosts, or you can harvest and store in vented root bags in the fridge for many months.
‘Red Meat’ Watermelon
The green skin and vibrant fuschia interior of this radish are what give it the “watermelon” name. These roots grow large (2-4”) and take up to 50 days to mature. They are sweet and delicious, perfect for fresh eating, fermenting, or winter salads. This variety will quickly bolt if sown in spring or summer, so be sure to wait until fall temperatures have cooled to plant ‘Red Meat’.
‘KN Bravo’ Purple Daikon
These gorgeous purple daikon radishes almost look tie-dyed on the interior. They are sweet and cold-tolerant, with roots averaging 4-6” long and nearly 3” wide. Perfect for fall salads or kimchi fermenting, ‘KN Bravo’ has an exceptional yield, vigor, and flavor.
‘Miyashige’ Japanese Daikon
This variety is a classic long white daikon traditionally harvested in the fall in Japan for pickling and storage. Roots are excellent for breaking up soil compaction and can grow up to 16-18” long. Sow ‘Miyashige’ in late July or early August in most regions and begin harvesting 50 days later. This variety holds in the ground or in refrigerator storage all winter long.
Caring for Radishes
There are many different steps you’ll need to take when caring for these plants. They are easy to care for, which is why they are great for beginners. But they do require a bit of finesse in order to maximize your harvest. Let’s look at what to expect at each stage.
Radishes are not super thirsty garden plants. They just require enough moisture to germinate and moderate moisture during growth. Depending on temperatures and weather, watering once or twice a week will typically suffice.
Don’t let the soil get waterlogged or too saturated as this can promote root rot. Use a thin mulch like leaves or straw around them if the soil is drying out too quickly and leaves appear wilted between waterings.
Soil and Fertility
Like most garden veggies, well-drained loamy soil is always ideal. Amending with quality organic compost and regularly broad forking or loosening your garden soil is the best way to keep it aerated and fluffy. Many radishes have a hard time with compaction because they can’t get their little taproot through heavy concrete-like clay.
Radishes are light feeders, but they still like plenty of phosphorus. Organic fertilizers like bone meal are a great addition to vegetable beds before planting. Kelp meal is a great source of trace minerals and micronutrients that they thrive off of. It is best to avoid fertilizing with nitrogen-rich fertilizers like feather meal or manure because too much nitrogen encourages more leafy growth rather than root bulb development.
Most radish varieties prefer the cooler weather of spring and fall. They thrive in temperatures between 40° and 70° Fahrenheit but tolerate temperatures as low as 20° and as high as 80°.
Mid-season radish varieties have been developed to resist bolting in the hot temperatures of summer, however, they may be spicier and less tender than their buffer-season counterparts. If you want to extend your harvest, you can keep the soil cool with even moisture and use a shade cloth over the plants.
Radishes prefer at least 6 hours of full or partial sunlight. They can be companion planted at the same time as veggies like tomatoes or peppers because, by the time those crops have grown tall, they are already harvested.
Even in the quick window of profusion, these humble veggies are still prone to problems. Alas, nobody is perfect! The primary culprits of problems are bolting, splitting, and a few pesky pests.
Bolting is the bane of any radish gardener’s existence! It happens when a plant transitions from vegetative growth (roots and greens) to reproductive growth (flowers and seeds). Radishes are very prone to bolting in the heat.
Once they start to shoot up toward the sky and put their energy into flowering, the flavor and texture of the radish are pretty much toast. The leaves get hairy and bitter, the roots get woody or pithy, and the
But there is an upside! Radish flowers are edible and sometimes consumed as a tasty tender radish raab (similar to broccoli raab). Simply harvest flower clusters just before they open and use them like sprouting broccoli.
Too much water or uneven amounts of water can cause their roots to expand and contract. If you forget to water and then suddenly irrigate heavily, your plants will likely split due to the sudden change in the water pressure inside their cells. Split radishes are perfectly fine to eat, but they are less optimal for selling or storage.
Their primary pests are the dreaded flea beetles. If you start to see tiny little holes on their leaves, don’t panic! Flea beetles are annoying and unsightly but don’t actually harm the plant root itself.
Keeping them out of your garden is as simple as using a row cover. This “exclusionary” pest control just prevents flea beetles from smelling your radishes and landing on the leaf surfaces. I use the lightest row cover possible so that the plants don’t get too hot underneath.
Another common pest is the cutworm. Unlike flea beetles, these guys can do some real damage to the roots. Cutworms are the larvae of a moth that lays its eggs in spring. They emerge in the evenings and start feeding at the base of your plants.
The most common solution is hand-picking the fat buggers out of the soil or using cardboard plant collars and diatomaceous earth around the bases of the plants. Diatomaceous earth has to be re-applied once it gets wet because it can no longer cut the insect’s exoskeleton.
Cabbage Root Maggot
Radish is, after all, a brassica, meaning it is susceptible to cabbage-family pests just like its cousins. Root maggots are nasty little creatures that hatch from eggs laid at the base of brassica plants in early spring.
They are ugly little white wormy creatures that crawl into and around their roots. They cause plants to wilt and die by feeding on the roots or girdling the base of the stem. The best deterrent is neem in the form of pellets or a diluted spray. We also recommend crop rotation of brassicas around different parts of the garden.
How To Harvest
The biggest mistake when growing radishes is simply letting them get too big. Large radishes get pithy and eventually woody. Pithy means the texture of the root becomes mealy, hollow inside, and a less than desirable texture.
For round salad radishes, harvest at ¾-2” in diameter. You can “thin” your crop by harvesting the largest radishes first and leaving the rest to grow a bit bigger before coming back.
Some varieties such as watermelon and purple daikon radishes can grow larger to 3-4” diameter. Classic white daikon radishes are skinny and up to 16” long. Check your seed packet!
The point is, the best plants are harvested small, crisp, and sweet. This crop grows very fast, so if you wait too long to pick them, you will miss the optimum harvest window.
Radishes can handle a light frost of 28-32° F without much stress. When it starts to get down to 26-28°, their foliage will likely burn. Some fall storage varieties will hold fine in the ground, while others will split or their cell walls will burst, rendering them pretty rubbery.
Cold hardiness in the garden always depends on gradual temperature changes and how established the plant is. Newly germinated plants stand no chance against a hard frost, but established plants may even sweeten up in the cold weather.
If a sudden hard freeze is coming, either harvest your entire batch, or use a thick row cover to keep them protected.
With all the colors, shapes, and flavors of radishes, who wouldn’t want them in their garden!? They are easy to grow and ready to harvest in the blink of an eye (at least from the perspective of “garden time”). They are great for school gardens and beginner growers of all types.
Grocery store radishes could never stand up to a garden-fresh radish. If you didn’t like radishes before, you may discover that you start craving the peppery, crisp flavor in your salads or on cheese platters.