Vegetable · Brassicaceae
Radish
Raphanus sativus
Few crops move faster: give it cool weather and steady water, and a radish is ready in weeks.
Full sun
Every 3–5 days
39–75°F · 4–24°C
22–60 days
Overview
The radish is the crop that rewards impatience. A member of the cabbage family, it goes from seed to harvest faster than almost anything else you can grow, with the quick salad types pulling in just three to five weeks. That speed makes it a favorite for filling gaps between slower vegetables and for handing beginners an early win.
Not every radish is a small red ball. The family runs from the round spring types you slice into a salad to the long white daikon radishes that want a full season and deep, loose soil, and even oddballs grown for their spicy seed pods instead of any root. What ties them together is a love of cool weather, since heat is what turns a sweet, crisp radish woody and harsh.
Radishes ask for little but reward a steady hand. Keep the soil evenly moist, thin the seedlings so each root has room, and pull them on time. Skip those steps and you trade crisp roots for cracked skins, sharp flavor, or a row of leafy tops with nothing underneath.
Care
The short version: full sun and cool weather, soil kept evenly moist with about an inch of water a week, loose ground without heavy nitrogen, and roots pulled promptly once they reach size.
Light
Radishes want full sun, at least 6 hours a day, though they'll take a little afternoon shade in warm weather. Too much shade pushes the plant toward leaves and away from a usable root.
Water
Keep the soil evenly moist, around an inch of water a week, and more in sandy ground or a heat spell. Steady moisture is what keeps the roots crisp and stops them cracking or turning hot and woody.
Soil
Plant in loose, well-drained sandy loam cleared of stones and compaction so the roots can swell without obstruction. A pH between 6.0 and 7.0 suits them well.
Temperature
This is a cool-season crop, happiest from about 39°F to 75°F (4°C to 24°C). Once the heat climbs, radishes bolt and the roots turn sharp and pithy.
Humidity
Ordinary outdoor humidity is all they need, so there's no figure to track. Even soil moisture matters far more than the air.
Feeding
Work some compost or well-rotted manure into the bed before sowing and that's usually enough. Go light on nitrogen, since a rich feed grows lush tops and leaves you with stunted roots.
Pruning
There's no pruning to do, but thinning is the job that counts. Once seedlings are up, thin to about 2 inches apart, or 4 to 6 inches for daikon, so each root has the room to size up.
Size & spacing
Plants run from about 6 to 35 inches (15 to 90 cm) tall depending on the type, with the long daikon at the upper end. Thin to 2 inches apart, wider for the big winter radishes, so roots can fill out and air can move.
When to plant
Radishes are a cool-season crop with no patience for summer heat. Direct sow the quick types in early spring as soon as the soil can be worked, then sow again from late summer into fall, with the long daikon and winter types timed for a fall harvest.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Direct sow in early spring (April-May) as soon as soil can be worked, and again in late summer to early fall (August-September); winter/daikon types are sown for fall harvest
- Harvest: Spring/salad types harvested 3-5 weeks after sowing; daikon and winter types harvested in fall
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most radish trouble shows up in the root or, just as often, in tops that grow at the root's expense. Catch the early signs and the fix is usually simple. Match what you see below, then adjust your timing, watering, or feeding.
Tunnels and rot riddling the roots
White legless larvae and brown tunnels inside the root point to cabbage root maggots, and a root they've been through is ruined. Dig out and bin any affected roots. Rotate away from brassicas, cover the bed at sowing, and skip beds that were recently manured.
Fix:
- Remove and discard affected roots
- Practice crop rotation away from brassicas
Big leafy tops but no radish underneath
When a radish pours everything into its greens and leaves you with a thread of a root, the usual culprit is too much nitrogen, often paired with rows that were never thinned. Heat, long days, and shade push it the same way. Cut the rich feeding, thin the seedlings to spacing, and sow in cool weather with at least 6 hours of sun.
Fix:
- Thin seedlings to recommended spacing
- Stop applying high-nitrogen fertilizer
- Sow during cool spring or fall weather in full sun
A flower stalk shoots up before the root is ready
This is bolting, and warm weather with lengthening days sets it off, sometimes helped along by drought or crowding that slows the plant down. Once the central stem stretches, the root turns woody and sharp. Pull what you can right away, then replant in the cool of spring or fall.
Fix:
- Harvest promptly before quality declines
- Replant in cooler spring or fall conditions
Roots turn woody, pithy, or fiery hot
A radish left in the ground too long goes tough and pithy and picks up a harsh, peppery bite, and drought and heat speed the decline. There's no walking it back once the texture turns. Pull radishes at peak size and keep the soil evenly moist while they grow.
Fix:
- Harvest at peak size
- Keep soil consistently moist during growth
Roots split open lengthwise
Splitting comes from swings in soil moisture, most often a heavy soak after the bed has gone dry, and from leaving roots in the ground past their prime. Water evenly so the roots grow at a steady pace, and pull them at the right size before they have a chance to crack.
Fix:
- Harvest at proper size
- Maintain even watering
Tiny shot-holes peppering young leaves
Those little round holes are the work of flea beetles, dark specks that spring away the moment you brush the row. Seedlings take the brunt of it, so slip a floating row cover over young plants to shut the beetles out and rotate where you grow your brassicas.
Fix:
- Use floating row covers over seedlings
- Monitor and manage early pressure
Toxicity
Good news here: the whole radish is safe. The roots, leaves, flowers, and seed pods are all edible for people, and the plant is harmless to pets and livestock. The only thing to note is that the cut root can sting sensitive skin a little.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Radish is safe for cats. A curious nibble of leaf or root may bring on a little gas or a loose stool, nothing more.
Dogs None
Dogs can have radish without worry. Plain pieces are fine in moderation, though a big helping of the spicy root might leave a dog a bit gassy.
Horses Safe
Horses tolerate radish and its tops without trouble. As with any fresh treat, keep the amount sensible so it stays a small part of the diet.
Rabbits Safe
Rabbits can eat the leafy radish tops happily, and the root is fine in small amounts. The greens are the better part for them.
Livestock Safe
Cattle, goats, and sheep graze radish tops and roots with no harm, and the crop is sometimes grown on purpose as forage.
Birds Safe
Backyard hens peck at radish greens and roots without any problem, and the leaves make a welcome bit of green.
People Safe
Radishes are a kitchen staple eaten raw or cooked, and the roots, leaves, flowers, and seed pods are all edible. Handling the cut root can sting sensitive skin a little.
Leaves and roots contain isothiocyanates that may cause mild skin irritation in sensitive individuals when handling, and the raw root is pungent.
Varieties
Hundreds of radishes exist, but a few keep showing up in seed racks and gardens. These are the ones worth knowing by name.
Cherry Belle
This is the classic round, bright red salad radish, and it sizes up in roughly three to four weeks.
Easter Egg
A mix that gives you roots in white, pink, red, and purple from a single sowing.
Sparkler
A round red radish marked by a clean white tip at the bottom.
Daikon (var. longipinnatus)
A long white winter radish that wants a longer season and deeper, looser soil to stretch into.
Rat's Tail (var. caudatus)
An oddball grown for its edible spicy seed pods rather than any root at all.
Companions
Radishes earn their keep beside slower crops, holding space and marking rows before they're pulled and the neighbors fill in.
Plant near
Lettuce: Quick-maturing radishes interplant well with lettuce, using space before the lettuce fills in.
Carrots: Radishes are sown as a fast marker crop with slow-germinating carrots and are pulled before the carrots need the room.
Cucumbers: Radishes are commonly interplanted with cucumbers as an early quick crop in the same bed.
How to propagate
Radishes come from seed and only from seed, sown right where they're meant to grow.
SeedEasy
Direct sow in early spring and again in late summer/fall · Germinates in about 3 to 7 days under cool, moist conditions
Radishes grow straight from seed sown where they will stand, since they don't transplant well. Drop the seeds about 1/4 to 1 inch deep in early spring and again in late summer or fall, and in cool, moist soil they sprout in just 3 to 7 days. Thin the seedlings early so each root has the room to size up.
Myths
Radishes need rich, heavily fertilized soil to grow big roots.
Pile on the nitrogen and you get a flush of leafy tops with barely a root to show for it. Radishes do their best in moderately fertile, well-prepared soil, not a heavily fed bed.
You can leave radishes in the ground and pick them whenever you like.
Left past maturity, the roots turn woody, pithy, and cracked, and the flavor sharpens to a harsh bite. Pull them promptly once they reach size to catch them at their best.