Onion
How far apart to plant onions, how many fit your bed, when to plant them and how many you need.
- In the row
- 2 to 4 in
- Between rows
- 12 to 18 in
- Per square foot
- 9
- Planting depth
- 0.25 to 0.5 in
- Start indoors
- 6 to 8 weeks before last frost
- Plant out
- 2 to 4 weeks before last frost
How many fit a raised bed
| Bed | At 5 in spacing | Square foot method |
|---|---|---|
| 4 x 4 ft | 81 | 144 |
| 4 x 8 ft | 171 | 288 |
| 3 x 6 ft | 98 | 162 |
Square grid with half the spacing kept clear at the bed edges.
Seeds, sets and transplants all go in at the same final spacing of 3 to 4 inches for bulbs; closer plantings can be thinned and the pulls used as green onions.
Bulbing is triggered by day length, so short-day onions suit the South and intermediate and long-day onions suit higher latitudes.
Onion calculators
Sources
- Virginia's Home Garden Vegetable Planting Guide: Recommended Planting Dates and Amounts to Plant (426-331), Virginia Cooperative Extension, Virginia Tech
- CMG GardenNotes #720: Vegetable Planting Guide, Colorado State University Extension
- Square Foot Gardening (class notes), University of Wisconsin-Extension, Taylor County
- How to Grow Onions in Your Garden, Utah State University Extension
- Onions: Key Growing Information, Johnny's Selected Seeds
- Soil temperature conditions for vegetable seed germination, Oregon State University Extension Service
- Easy Gardening: Planning a Garden (E-289), Texas A&M AgriLife Extension