Vegetable · Brassicaceae
Radish
Raphanus sativus
Want a harvest that's ready almost before you're done waiting? Give a radish cool weather and steady water.
Full sun
Every 3–5 days
39–75°F · 4–24°C
22–60 days
Overview
If you're impatient, radishes are your kind of crop. They're part of the cabbage family, and they go from seed to dinner faster than just about anything, with the quick salad types ready in only three to five weeks. That's why they're such a great first crop and a handy way to fill gaps between slower veg.
And no, they're not all little red balls. You've got the round spring types for salads, the long white daikon that wants a full season and deep, loose soil, and even a few oddballs grown for spicy seed pods instead of a root. What do they all share? A soft spot for cool weather, since heat is what turns a crisp radish woody and harsh.
The nice part is that radishes don't ask for much. Keep the soil evenly moist, thin the seedlings so every root has some elbow room, and pull them on time. Skip any of that and you'll swap crisp roots for cracked skins, a sharp bite, or a row of leaves with nothing underneath.
Care
The short version: radishes like full sun and cool weather, soil that stays evenly moist with about an inch of water a week, loose ground that isn't loaded with nitrogen, and roots pulled the second they're big enough. That's really all there is to it.
Light
Radishes really want full sun, at least 6 hours a day, though they'll put up with a little afternoon shade when it's warm. Give them too much shade, and they'll spend their energy on leaves instead of the root you're after.
Water
Try to keep the soil evenly moist, roughly an inch of water a week, and a bit more if your soil's sandy or the weather turns hot. That steady moisture is what keeps the roots crisp and stops them cracking or going hot and woody.
Soil
Radishes do best in loose, well-drained sandy loam with the stones and hard bits cleared out, so the roots can swell without hitting anything. A pH somewhere between 6.0 and 7.0 suits them just fine.
Temperature
This is a cool-weather crop through and through, happiest around 39°F to 75°F (4°C to 24°C). Once it gets hot, radishes bolt and the roots go sharp and pithy, so it's really a spring and fall thing.
Humidity
You don't need to think about humidity here. Regular outdoor air is plenty, so there's no number to chase. What actually matters is even moisture in the soil, not the air around the leaves.
Feeding
Mix a little compost or well-rotted manure into the bed before sowing and you're usually set. Go easy on nitrogen, though, because a rich feed just grows big leafy tops and leaves the roots small.
Pruning
There's nothing to prune here, which is nice. Thinning is the real job: once the seedlings show up, thin them to about 2 inches apart, or 4 to 6 inches for daikon, so each root has room to bulk up.
Size & spacing
Depending on the type, plants reach about 6 to 35 inches (15 to 90 cm) tall, with the long daikon at the tall end. Thin to roughly 2 inches apart, more for the big winter radishes, so the roots can fill out and air can get through.
When to plant
Here's the thing about radishes: they can't stand summer heat. So sow the quick types right in the ground in early spring as soon as it's workable, then go again from late summer into fall. The long daikon and winter types? Those you time 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 turns up in the root, or in a mop of leaves that grew instead of one. Don't worry, though, because these are easy to spot and usually easy to fix. Find what matches below, then tweak your timing, watering, or feeding.
Tunnels and rot down inside the roots
White legless grubs and brown tunnels inside a root mean cabbage root maggots, and honestly, a root they've hit is done for. Dig those out and toss them. Then rotate away from brassicas, cover the bed when you sow, and skip any ground that's been manured recently.
Fix:
- Remove and discard affected roots
- Practice crop rotation away from brassicas
Loads of leaves, barely any radish
Getting a big leafy top and almost no root? That usually points to too much nitrogen, especially when the row never got thinned. Heat, long days, and shade all nudge it the same direction. So back off the rich feeding, thin the seedlings out, 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 pops up too soon
That shooting stalk means the plant's bolting, and it's triggered by warm weather and longer days, sometimes with a nudge from drought or crowding. Once the stem stretches up, the root goes woody and sharp. Pull whatever's still good, then have another go when spring or fall cools things down.
Fix:
- Harvest promptly before quality declines
- Replant in cooler spring or fall conditions
Roots gone woody, spongy, or blazing hot
Leave a radish in the ground too long and it turns tough and spongy with a harsh, peppery kick, and heat and drought only speed that up. Once the texture's gone, there's no fixing it. So pull them at their best and keep the soil evenly moist while they grow.
Fix:
- Harvest at peak size
- Keep soil consistently moist during growth
Roots that crack right down the side
Splitting comes from moisture that jumps around, usually a big soak right after the bed's gone dry, plus roots that sat too long. Keep the watering even so growth stays steady, and pull the roots at the right size before they get a chance to crack.
Fix:
- Harvest at proper size
- Maintain even watering
Tiny holes dotting the young leaves
See little round holes all over? That's flea beetles, those tiny dark bugs that hop off the second you get close. Seedlings cop the worst of it, so throw a floating row cover over the young plants and move your brassicas somewhere new each year.
Fix:
- Use floating row covers over seedlings
- Monitor and manage early pressure
Toxicity
Good news, and it's about as good as it gets: the whole radish is safe to eat. The root, leaves, flowers, and seed pods are all fair game, and it won't hurt your pets or livestock either. The only catch? A freshly cut root can sting sensitive skin a little.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are totally fine with radish. A little taste of the leaves or root might give them some gas or a loose stool, but that's about it.
Dogs None
Dogs can have radish, no problem. A few plain bits are fine in moderation, though a big pile of the spicy root might make a dog a little gassy.
Horses Safe
Horses are fine with radish and its tops. Like any fresh treat, just keep the amount reasonable so it stays a small part of their diet.
Rabbits Safe
Rabbits will happily chomp the leafy tops, and a bit of the root is fine too. For them, the greens are really the better part.
Livestock Safe
Cattle, goats, and sheep can graze the tops and roots with zero trouble, and radish even gets grown on purpose as forage.
Birds Safe
Backyard chickens love pecking at the greens and roots, and the leaves are a nice little treat for them.
People Safe
For people, radish is a kitchen regular, raw or cooked, and you can eat the root, leaves, flowers, and seed pods. Just know a freshly cut root can sting sensitive skin a bit.
Leaves and roots contain isothiocyanates that may cause mild skin irritation in sensitive individuals when handling, and the raw root is pungent.
Varieties
There are hundreds of radishes, but you'll keep bumping into the same few on the seed rack. So here are the ones worth knowing by name.
Cherry Belle
It's the classic round, bright red salad radish, and it's ready in about three to four weeks.
Easter Egg
Sow it once and you'll get roots in white, pink, red, and purple all together.
Sparkler
A round red radish that's easy to spot thanks to its clean white tip at the bottom.
Daikon (var. longipinnatus)
The long white winter radish, and it wants a longer season plus deep, loose soil to really stretch out.
Rat's Tail (var. caudatus)
A quirky one that's grown for its edible spicy seed pods rather than any root.
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 that's it, popped straight into the spot where they'll 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 go straight into the ground where they'll grow, since they don't take well to being moved. Pop 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'll be up in just 3 to 7 days. Thin the seedlings early so each one has room to make a decent root.
Myths
You've got to pile on fertilizer to get big radish roots.
Nope. Load up the nitrogen and you'll get a ton of leaves and hardly any root. Radishes are happiest in moderately fertile, well-prepared soil, not a heavily fed bed.
Radishes will sit happily in the ground until you get around to picking them.
Not really. Left too long, the roots turn woody, pithy, and cracked, and the flavor gets sharp. Pull them as soon as they're sized up and they'll taste their best.