Pumpkin in Zone 4a & 4b
Cucurbita pepo
Yes, pumpkin grows in zones 4a and 4b. Plant it outside May 22–May 29.
When to plant pumpkin in zone 4b
Zones 4a and 4b 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 22–May 29 |
| Estimated harvest | Sep 9–Sep 16 (~110 days after direct-sowing) |
Spacing: about 10 square feet per plant (square-foot-gardening spacing). Mature height: 1-1.5 ft.
Plant alongside it in zone 4b
These go outside within two weeks of pumpkin in zone 4b, so one planting day can cover them.
- TomatoMay 29–Jun 5
- Bush BeansMay 22–May 29
- CucumberMay 22–May 29
- ZucchiniMay 22–May 29
- Winter SquashMay 22–May 29
- BroccoliniMay 15–May 22
Pumpkins ask for more room and more patience than almost anything else in the garden: around 110 days from seed to harvest, and vines that sprawl far enough that planning calls for a mere tenth of a plant per square foot, in practice, that means giving one plant several square feet to itself.
How pumpkin fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Pumpkin needs about 110 days from sowing to first harvest.
Pumpkin planting windows in every zone
Zone 4b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 3a & 3b | Not usually | Jun 6–Jun 13 | Sep 24–Oct 1 |
| 4a & 4b (your zone) | Not usually | May 22–May 29 | Sep 9–Sep 16 |
| 5a & 5b | Not usually | May 17–May 24 | Sep 4–Sep 11 |
| 6a & 6b | Not usually | May 2–May 9 | Aug 20–Aug 27 |
| 7a & 7b | Not usually | Apr 17–Apr 24 | Aug 5–Aug 12 |
| 8a & 8b | Not usually | Apr 1–Apr 8 | Jul 20–Jul 27 |
| 9a & 9b | Not usually | Feb 22–Mar 1 | Jun 12–Jun 19 |
| 10a & 10bSpring window | Feb | Mar | ~110 days after transplanting |
| Summer window | Jun–Jul | Jul–Aug | ~110 days after transplanting |
Harvest dates are about 110 days after the sow or plant-out date.
Good companions
- Sweet Corn: The same 'three sisters' mechanism as winter squash: WSU Extension confirms pumpkin's broad leaves shade the soil, suppressing weeds and reducing evaporation around corn.
Where to buy pumpkin seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's pumpkin seeds)
Varieties we recommend, and where to get them:
- Racer (F1): Bred by Johnny's with the University of New Hampshire specifically for earliness, at 85 days against the usual 110, on short vigorous vines. Buy: High Mowing Organic Seeds Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing pumpkin" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Plan your beds in the Garden Designer →
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Growing Pumpkin in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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