Growing kale in zone 3a
(Zone 3a = an average winter low of -40°F to -35°F.)
In USDA zone 3a, the typical last spring frost is May 29 and the first fall frost is September 5. Here is when to plant kale against those dates.
Typical timing
Zone 3a planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 3a 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 Kale in Your GardenUtah State University Extension. Supports indoor seed-starting timing (derived), outdoor transplant timing (direct), direct-sowing timing (direct), and fall direct-sowing timing (derived).
Method note
All fields. Plant out 4-5 weeks before last frost (transplant or seed), 5-6 weeks to grow transplants (sow-indoors re-expressed against last frost), spacing 12 inches in rows 2 feet (page summary gives 12-18 inches; the planting section figure is stored), depth 1/4 to 1/2 inch (lower bound stored), water 1-2 inches/week (lower bound stored), insect table. Fall window converted from 'plant 50-75 days before maturity, maturity 2-3 weeks after first fall frost' at 7 days/week.
These are zone 3a averages
Computed from 17 ZIP codes in zone 3a. 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.