Growing rhubarb in zone 4b
(Zone 4b = an average winter low of -25°F to -20°F.)
In USDA zone 4b, the typical last spring frost is May 8 and the first fall frost is October 1. Here is when to plant rhubarb against those dates.
Typical timing
Zone 4b planting schedule
Evidence trail
How these dates are built
Sprout applies the cited planting offsets to the typical zone 4b 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.
- Growing rhubarb in home gardensUniversity of Minnesota Extension. Supports indoor seed-starting timing (direct).
Method note
Perennial lifecycle, all-day-sun requirement, three-foot (36 inch) plant area, indoor seed start six weeks before last frost, 1 inch water per week, and the pest/disease list from this page. Botanically a vegetable used as a fruit; recorded as category 'vegetable' per the build brief. UMN states soil pH is not important for rhubarb, so soilPh is omitted; hardiness is given as a lower bound only (hardy zone 4, worth trying zone 3) with no upper bound, so zoneRange is omitted.
These are zone 4b averages
Computed from 1,251 ZIP codes in zone 4b. 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.