PlantSowGrowHow to grow Onion Sets (Red Baron)
Allium cepa
🥕 Vegetable
🌱 Grown each year
Deep-red, flavoursome onions from sets — great raw in salads and for pickling, and they store well.
At a glance: Sow mid March to late April, harvest from mid July.
When to sow, plant and harvest
JanFebMarAprMayJunJulAugSepOctNovDec
Sow outdoors
Harvest
Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.
Growing Onion Sets (Red Baron): what it needs
- Light
- Full sun · 6+ hours a day
- Watering
- Water in dry spells, especially as crops swell
- Soil
- Firm, well-drained soil
- Spacing
- 10 cm, rows 30 cm apart
- In pots
- Only in large containers
- Feeding
- A general fertiliser before planting
- Harvest
- About 120 days from sowing
- Hardiness
- USDA zones 3–9
Step by step
- Mid March – late April · 4 weeks before the last spring frost
Plant Sets
Plant sets 10 cm, rows 30 cm apart apart in rows.
- 14–28 days after “Plant Sets” · Late March – mid April
Look for Shoots
Green shoots should be showing. Keep weeds down — these crops hate competition.
- 45–60 days after “Look for Shoots” · Mid May – late May
Remove Flower Spikes
Snap off any flower stems that appear — they ruin storage.
- 21–35 days after “Remove Flower Spikes” · Early June – mid June
Weed and Water
Hoe off weeds between rows and water in dry spells — even moisture gives better crops.
- 120–150 days after “Plant Sets” · Mid July – mid August
Harvest
When the leaves yellow and flop over, lift on a dry day.
- 7–21 days after “Harvest” · Late July – early August
Dry and Store
Dry for 2 weeks until the skins rustle, then store in nets somewhere cool.
