Rainbow Radish

How to sow

Sow 2 cm, loose compost. Use peat-free coco. Keep the surface just moist.

Germination 3–5 days in the crop record.

Growing

1. Sowing — Day 0. Sow individual seeds 2cm apart, 1cm deep. Water gently. Use a pot at least 15cm deep.
2. Germination — Days 3–5. Seedlings emerge rapidly. Keep moist. Thin to 3cm apart if crowded.
3. Leaf growth — Weeks 1–2. Keep soil consistently moist. Irregular watering causes cracking.
4. Root swelling — Weeks 2–3. You can see the top of the radish at the surface — this is normal.
5. Harvest — Weeks 3–4. Pull gently. Wash. Eat. Oversize radishes become woody and hollow.
6. Succession sow — Every 2–3 weeks. Radishes are single-harvest. Sow the next batch the day you pull the last.

Keep at or above 5°C where the crop record sets a floor.

Harvest

First cut around 4 weeks.

Pull gently. Wash. Eat. Oversize radishes become woody and hollow.

Common mistakes

• Leaving them too long — Oversize radishes turn woody, pithy, and hollow. The harvest window is narrow. Pull at 2–3cm diameter — usually week 3–4. Check daily from week 3.
• Pot too shallow — Radishes need root depth to swell properly — shallow pots produce stunted roots. Use a pot at least 15cm deep. Remove stones or dense compost lumps.
• Inconsistent watering — Irregular watering causes radishes to crack and split. Water every 2 days consistently. Soil should stay evenly moist, never dry then flooded.
• Sowing too densely — Crowded radishes compete and produce thin, unusable roots. Sow 2cm apart and thin to 3cm. Each radish needs room to swell.

In the kitchen

• Butter and salt — Halve fresh radishes, serve with cold salted butter on a board. French bistro classic.
• Salad component — Slice thinly or quarter. Add to green salads for crunch and colour.
• Pickle — Quick pickle in rice vinegar, sugar, and salt for 30 minutes. Use on tacos and rice bowls.
• Roasted — Halve and roast at 200°C with olive oil and thyme. Mellows the peppery bite completely.
• Radish leaf pesto — Blend young radish leaves with garlic, parmesan, pine nuts, and olive oil. Zero waste.

Questions

Sources

1. Rainbow Radish Seed Pack
2. Coco Soil treatise
3. HubWīk contents
4. Grower knowledge + RHS Growing Guides