Growing sweet corn in zone 9b
(Zone 9b = an average winter low of 25°F to 30°F.)
In USDA zone 9b, the typical last spring frost is February 1 and the first fall frost is December 9. Here is when to plant sweet corn against those dates.
Typical timing
Zone 9b planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 9b 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.
- How to Grow Sweet Corn in Your GardenUtah State University Extension. Supports direct-sowing timing (normalized) and days to maturity (direct).
Method note
Direct-sow window start (plant after the last frost-free date; the two-week span follows the store convention from the tomato exemplar), days to maturity (60 to 90 from planting), full sun. USU spacing (7-9 in, rows 24-30 in) differs from UMN; UMN stored as the primary source.
These are zone 9b averages
Computed from 2,081 ZIP codes in zone 9b. Your town's frost dates vary; enter your ZIP for dates built on your nearest weather station.
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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.