Dahlia in Zone 10a & 10b
Dahlia spp.
When to plant dahlia in zone 10b
Zones 10a and 10b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Dahlia doesn't transplant well, or doesn't need the extra time indoors.
| Window | Spring window |
|---|---|
| Start indoors | Not typically started indoors |
| Direct sow / transplant outside | Feb–Apr |
| Estimated bloom | May 2–Jul 29 (~90 days after direct-sowing) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-5 ft.
Zone 10b dates sourced from growinginthegarden.com.
Dahlia is the one flower in this garden that doesn't start as seed at all. It grows from a tuber, planted like a potato, which changes the whole rhythm of how it goes in the ground and comes out at season's end. Blooms run from small pompoms to dinner-plate-sized flower heads, in nearly every color except true blue, on plants that range from 1 to 5 feet depending on type.
How dahlia fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Dahlia needs about 90 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Dahlia.
Where to buy dahlia bulbs
We haven't vetted bulb/tuber suppliers yet. Our seed-supplier list below doesn't carry these. The growing-guide source cited above is a good starting point for where to buy.
See it growing
Search YouTube for "growing dahlia" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 10b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
Pin this for later
Growing Dahlia in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
Save to Pinterest