Growing dahlia in zone 10a
(Zone 10a = an average winter low of 30°F to 35°F.)
In USDA zone 10a, the typical last spring frost is January 17 and the first fall frost is January 13. Here is when to plant dahlia against those dates.
This near-frost-free pattern wraps across New Year. The listed first fall frost falls in the following calendar year.
Typical timing
Zone 10a planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 10a frost anchors. The result is a planning baseline for the zone, not a local weather forecast.
- USDA Plant Hardiness Zone Map, 2023USDA Agricultural Research Service / Oregon State University PRISM Group. Supports the USDA hardiness-zone band.
- U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information. Supports the median spring and fall freeze dates.
- The Dirt on DahliasPenn State Extension. Supports outdoor transplant timing (normalized).
Method note
Tuber planting after spring frost danger (start-only anchor expressed as weeks 0-2), depth 4 to 6 inches (4 recorded), full sun, deer browsing, winter tuber storage at 32 to 50 F to prevent rot. Lifecycle recorded as annual because PSU directs digging the tender tubers every fall after a hard frost. No spacing, pH, or water-rate numbers given, so those fields are omitted.
These are zone 10a averages
Computed from 1,125 ZIP codes in zone 10a. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.
Get my exact datesKeep planning
Put these dates to work
The plant profile covers spacing, light, water, soil, and source-backed timing details. The growing guide covers preparation, care, and harvest technique.