🧅
Onion
Red (Red Wethersfield)
AlliumsDirect SowTransplant
☀️
Sun
full sun
💧
Water
Every 5 days
🌱
Germination
10 days
🕐
Days to harvest
100 days
📏
Planting depth
0.5 inches deep
↔️
Row spacing
12 inches
When to Plant
Start indoors 10 wks before last frost
Growing Guide
Soil: well-drained loamy · pH 6.0–7.0
Same as yellow onion. Red onions are slightly more sensitive to wet conditions — ensure especially good drainage.
- Start indoors 10–12 weeks before last frost
- Transplant as small as possible (pencil-thick stems) to avoid triggering bolting
- Plant in full sun — even partial shade reduces bulb size significantly
- Avoid nitrogen-heavy fertilizers late in the season; switch to phosphorus/potassium to firm bulbs
Care
💧 Water every 5 days
🌿 Fertilize every 21 days
📐 Spacing: 4 inches apart · 12 inches between rows
Recommended sub-rows: 3
Harvest & Storage
Ready in 100 days with a harvest window of 14 days.
- Red onions are ready slightly earlier than yellow types — check at 90–100 days after transplanting
- Handle especially carefully; red skins bruise and nick more visibly than yellow
- Sun-cure in the field for a day if weather allows before bringing indoors
Storage
Red onions store 3–5 months (shorter than yellow). Best kept at room temperature if using within a few months. Refrigerate cut portions.
Companion Planting
Grows well with:
carrotbeet
Keep away from:
bean
Essential Tools
- Transplant dibber or trowel
- Garden fork (harvest)
- Mesh bags (curing and storage)
- Grow lights (starting from seed)
Pests & Diseases
- Onion thrips: silvery streaking on leaves — reflective mulch deters; avoid drought stress
- Fusarium basal rot: mushy base — 3-year crop rotation essential
- Downy mildew: blue-grey fuzz in wet weather — improve plant spacing and drainage
- Red varieties tend to be somewhat more disease-resistant than yellow types overall