Sweet Pea in Zone 5a & 5b
Lathyrus odoratus
When to plant sweet pea in zone 5b
Zones 5a and 5b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Sweet Pea doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | Mar 29–Apr 5 |
| Estimated bloom | Jun 22–Jun 29 (~85 days after direct-sowing) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 5-8 ft.
Sweet pea breaks from the usual "wait for frost to pass" rule. It goes into the ground about 6 weeks before your last frost date, while the ground is still cold, because the seed needs that early start and darkness to germinate well. It climbs to 5 or 6 feet and covers itself in ruffled, butterfly-shaped blooms in pink, purple, white, or red, and it's grown here purely for fragrance and cut-flower value, not for the table.
How sweet pea fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Sweet Pea needs about 85 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Sweet Pea.
Where to buy sweet pea seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing sweet pea" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Sweet Pea in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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