🌱 Radish

Raphanus sativus
The instant gratification of the vegetable world — sow on Monday, brag by next month.
Sun
Full sun (6+ hours); tolerates light shade in hot climates
Days to harvest
20–30 days from seed
Spacing
1 inch apart in rows 6 inches apart; thin ruthlessly — crowded radishes grow all top and no bottom
Soil pH
6.0–7.0

How to grow

Radishes are the gateway crop: if you can mess these up, gardening may not be your thing, and almost nobody messes these up. Direct-sow seeds a half inch deep as soon as soil can be worked in spring, or in fall once nights cool off. They germinate in soil as cool as 45°F, which is basically the plant equivalent of showing up to work in a blizzard and thriving.

The catch: radishes are cool-season sprinters that panic in heat. Once daytime temps climb past 80°F, they bolt — shooting up a flower stalk and turning the root woody, pithy, and spicy enough to clear sinuses. In Florida and the Gulf South, that means radishes are a fall-through-spring crop, full stop. Succession-sow every 10 days for a continuous supply instead of one giant harvest you'll never eat.

Keep the soil consistently moist and loose. Radishes grown in compacted or rocky soil fork, split, and develop the kind of abstract shapes that belong in a modern art museum, not a salad. A light mulch helps hold moisture; a heavy hand with nitrogen grows gorgeous leaves and disappointing roots, because the plant decides foliage is the whole point.

Water & feeding

Even, consistent moisture is everything — about an inch a week. Let them dry out and they turn hot and hollow; drown them and they split. A 1/4-inch top-dress of worm castings at sowing gives seedlings a gentle nutrient head start without the nitrogen blast that makes tops at the expense of roots.

Common problems

  • Flea beetles (tiny black jumpers chewing shotgun holes in leaves): row cover from day one is the simplest fix; the damage is cosmetic on a 25-day crop anyway.
  • Bolting in heat: sow only when nights are cool; choose heat-tolerant varieties like 'Sora' for shoulder seasons.
  • Woody/pithy roots: almost always inconsistent watering or harvesting too late — pull them the moment they size up, not 'next weekend.'
  • Root maggots: floating row cover blocks the flies that lay the eggs; rotate beds so you're not planting where brassicas grew last season.

Harvest

Pull when roots are 1–1.5 inches across — about the size of a large marble. Any bigger and they get pithy fast. Don't forget the greens: they're peppery, edible, and great wilted with garlic.

Nerdy fact: Daikon-type radishes are sold to farmers as 'tillage radishes' because their taproots can punch through compacted soil layers — a process agronomists literally call biodrilling. Your salad garnish moonlights as a soil-remediation contractor.

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