Sweet Pea in Zone 9a & 9b
Lathyrus odoratus
When to plant sweet pea in zone 9b
Zones 9a and 9b 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 | Jan 4–Jan 11 |
| Estimated bloom | Mar 30–Apr 6 (~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 9's season
Zone 9b's frost-free window runs about 293 days, from February 15 to December 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 9b 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 9b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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