Scallion (Green Onion) in Zone 3a & 3b
Allium fistulosum
Yes, scallion (green onion) grows in zones 3a and 3b. Plant it outside May 16–May 23.
When to plant scallion (green onion) in zone 3b
Zones 3a and 3b share the same average frost dates, so this page covers both.
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | May 16–May 23 |
| Estimated harvest | Jul 15–Jul 22 (~60 days after direct-sowing) |
Spacing: 9 per square foot (square-foot-gardening spacing). Mature height: 1-1.5 ft.
Plant alongside it in zone 3b
These go outside within two weeks of scallion (green onion) in zone 3b, so one planting day can cover them.
- OnionMay 9–May 16
- RadishMay 2–May 9
- CabbageMay 16–May 23
- BroccoliMay 16–May 23
- Flower SproutsMay 16–May 23
- Gai Lan (Chinese Broccoli)May 16–May 23
Scallions are one of the easiest alliums to grow: direct-sown, no bulbing to manage, and forgiving enough to go in the ground before your last frost while other crops are still waiting on warmer soil. They're also one of the densest plantings you can make in a small bed.
How scallion (green onion) fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Scallion (green onion) needs about 60 days from sowing to first harvest.
Scallion (Green Onion) planting windows in every zone
Zone 3b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 2a & 2b | Not usually | May 6–May 13 | Jul 5–Jul 12 |
| 3a & 3b (your zone) | Not usually | May 16–May 23 | Jul 15–Jul 22 |
| 4a & 4b | Not usually | May 1–May 8 | Jun 30–Jul 7 |
| 5a & 5b | Not usually | Apr 26–May 3 | Jun 25–Jul 2 |
| 6a & 6b | Not usually | Apr 11–Apr 18 | Jun 10–Jun 17 |
| 7a & 7b | Not usually | Mar 27–Apr 3 | May 26–Jun 2 |
| 8a & 8b | Not usually | Mar 11–Mar 18 | May 10–May 17 |
| 9a & 9b | Not usually | Feb 1–Feb 8 | Apr 2–Apr 9 |
| 10a & 10b | Not usually | Jan 16–Jan 23 | Mar 17–Mar 24 |
Harvest dates are about 60 days after the sow or plant-out date.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
- Carrot: Same allium/carrot pest-masking effect measured for onion and carrot (Uvah & Coaker 1984): a real, peer-reviewed field study, not folklore. The reverse direction (carrot masking onion from onion fly) wasn't part of that study and is the less-supported half of this pairing.
- Lettuce: Space-efficient interplant with non-competing root depths.
Where to buy scallion seeds
High Mowing Organic Seeds (each supplier's scallion seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing scallion (green onion)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Plan your beds in the Garden Designer →
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Growing Scallion (Green Onion) in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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