Growing swiss chard 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 swiss chard 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 Swiss Chard in Your GardenUtah State University Extension. Supports indoor seed-starting timing (derived), outdoor transplant timing (normalized), direct-sowing timing (direct), and fall direct-sowing timing (direct).
Method note
All fields. Spring: transplants near the last frost-free date, seed 3-4 weeks earlier, 5-6 weeks to grow transplants (sow-indoors re-expressed against last frost). Fall: FAQ gives plant 3-4 weeks before the first fall frost (the body text pins fall maturity 2-3 weeks before first frost with a 50-75 day lead; the simpler FAQ statement is stored). Spacing 6 inches in rows 12 inches, depth 1/2 inch, water 1-2 inches/week (lower bound stored), pest table.
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.