Growing tomatillo 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 tomatillo 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 Tomatillos in Your GardenUtah State University Extension. Supports indoor seed-starting timing (derived), outdoor transplant timing (normalized), direct-sowing timing (direct), and days to maturity (direct).
Method note
All fields. Start indoors 6-8 weeks before the planting date; transplant out after frost danger (soil over 60F), stored as 1-2 weeks after last frost with sow-indoors re-expressed against that window. Direct seed about 2 weeks before last frost with plastic mulch. Transplants 2 feet apart in rows 3 feet (hills 24-36 inches); plantsMax 36 reflects the hill range. Seed depth 1/2 inch, water 1-2 inches/week (lower bound stored), harvest 60-75 days from transplanting. Powdery mildew, viruses (aphid/leafhopper transmitted), root rots, aphids, flea beetles. Plant at least two for pollination (not self-fruitful).
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.