How to Grow Radishes
Raphanus sativus
The fastest vegetable you can grow — ready in as little as three weeks.
By the Plants by Zone Editorial Team · Reviewed June 1, 2026
About radishes
Radishes are the instant gratification crop: many varieties go from seed to harvest in just 3–4 weeks. They’re a cool-season root that’s ideal for filling gaps, interplanting, and getting kids excited about gardening. Sow little and often in spring and fall for a steady supply of crisp, peppery roots.
When to plant and harvest radishes
Timing is relative to your frost dates. Find your USDA zone for exact dates, or browse the month-by-month calendars.
Start seeds indoors
Never — direct-sow
Transplant outdoors
Direct-sow only
Direct sow
4 weeks before last frost, then succession-sow; again in fall
Harvest
Spring and fall, continuously
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How to grow radishes step by step
- 1
Direct-sow ½ in deep and thin to 1–2 in for room to bulb.
- 2
Keep soil evenly moist for fast, mild, crisp roots.
- 3
Succession-sow a short row every 1–2 weeks.
- 4
Harvest promptly — radishes turn woody and hot if left too long.
Common problems growing radishes
⚠ All leaves, no root
Too much nitrogen, crowding, or heat — thin well and grow in cool weather.
⚠ Woody, pithy, or hot roots
Harvested too late or grown in heat — pick young and grow in spring/fall.
⚠ Flea beetles (shot-holes in leaves)
Use row cover; roots usually still fine.
✗ Keep away from
🧺 Harvesting radishes
Pull as soon as roots reach full size — radishes don’t hold well in the ground and quickly turn pithy and pungent. Fall crops are milder and crisper than spring ones.
Radishes: frequently asked questions
When should you plant radishes?＋
In most regions you start seeds indoors never — direct-sow, then transplant direct-sow only — or direct sow 4 weeks before last frost, then succession-sow; again in fall. Timing is relative to your last frost, so find your USDA hardiness zone for the exact planting dates where you live.
How fast do radishes grow?＋
Spring varieties mature in just 3–4 weeks, making them the quickest vegetable in the garden.
Why do my radishes have no bulb?＋
Usually crowding, excess nitrogen, or heat. Thin seedlings, avoid rich feeding, and grow them in cool weather.
Sources & review
Written and maintained by the Plants by Zone Editorial Team. Planting times are based on USDA hardiness zones and NOAA frost-date normals, with care guidance drawn from Cooperative Extension sources. Last reviewed June 1, 2026.
USDA Plant Hardiness Zone MapNOAA U.S. climate normalsCooperative Extension
Grow radishes in your zone
See exactly when to plant and what else to grow alongside radishes, tailored to your USDA hardiness zone.
