Growing nasturtium in zone 4a
(Zone 4a = an average winter low of -30°F to -25°F.)
In USDA zone 4a, the typical last spring frost is May 12 and the first fall frost is September 28. Here is when to plant nasturtium against those dates.
Typical timing
Zone 4a planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 4a 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.
- Nasturtium, Tropaeolum majusUniversity of Wisconsin-Madison Division of Extension (Wisconsin Horticulture). Supports indoor seed-starting timing (direct) and direct-sowing timing (normalized).
Method note
Lifecycle annual (perennial only in zones 9 to 11), indoor sowing 4 to 6 weeks before last frost, direct sow after all danger of frost (start-only anchor expressed as weeks 0-2), 1/2 inch seed depth, spacing 10 to 12 in, full sun (tolerates light shade with reduced bloom), problems (imported cabbageworm, aphids, leafminers). No soil pH or per-week inch water rate given, so those fields are omitted; do-not-fertilize guidance noted. Transplant omitted because the page states nasturtium does not transplant well.
These are zone 4a averages
Computed from 795 ZIP codes in zone 4a. 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.