White Icicle

Yellowing with ragged holes is often flea beetle damage, while soggy spots and wilting can indicate damping-off in cool, wet soil. Cover seedlings with a fine insect net or row cover immediately after sowing, and keep the bed weed-free to reduce flea beetle habitat. Water at the soil level and avoid keeping the seed row constantly wet to prevent damping-off; if you see damping-off, remove affected seedlings and improve drainage before resowing in another spot.

Harvest at about 30 days, or as soon as the roots are clearly elongated and firm—typically when they reach roughly the size of a thumb and the shoulders show above the soil. Don’t wait too long after they’re full size, because Brassicaceae radishes (including Raphanus sativus) can become woody and hot-tasting. Pull one to check firmness; if it bends easily or feels soft, give the rest 2–3 more days and recheck.