When to plant cucumbers in Billings, Montana
May 24 – June 7
Transplant outdoors · typical Billings yearClimate basis: NOAA station Billings Wtp, MT (USC00240802), 13 mi (21 km) from downtown Billings (ZCTA 59101 centroid), elevation 3097 ft, on the 1991–2020 climate normals. Transplant cucumbers outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (May 10). One year in ten still freezes after May 24.
The Billings year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 24
Every method, with its sources
Start seeds indoors
Apr 26 – May 3Sow in individual pots 3–4 weeks before the outdoor window opens (UNH 3–4 weeks; Missouri G6570 3–5 weeks, sown directly in pots). Anchored to the median last spring freeze (May 10). University of New Hampshire Extension · University of Missouri Extension
Transplant outdoors
May 24 – Jun 7UNH allows setting out 1–2 weeks after frost; Purdue's very-tender class (at least 2 weeks after) is the more conservative and is used. Anchored to the median last spring freeze (May 10). Purdue University Extension · University of New Hampshire Extension
Direct-sow outdoors
May 24 – Jun 7Purdue: very tender — sow at least two weeks after the average last frost (UNH adds: when soil reaches 70°F). Penn State's earliest sowing (May 11 for a May 1 frost) is slightly earlier; the later Purdue rule is used. Anchored to the median last spring freeze (May 10). Purdue University Extension · Penn State Extension (York County Master Gardeners)
Variety assumption: Assumes an average slicing variety (about 55–70 days from seed; Penn State lists 70).
These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.
Crop rule sources (4)
- University of New Hampshire Extension: Growing Vegetables: When to Plant Your Vegetable Garden [fact sheet] (accessed 2026-07-24)Per-crop 'time from seed to transplant' and 'safe to set out in garden' relative to last frost.
- University of Missouri Extension: Starting Plants Indoors from Seeds (G6570) (accessed 2026-07-24)Weeks needed to grow vegetable transplants indoors (Table 2).
- Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.
- Penn State Extension (York County Master Gardeners): Vegetable Seed Planting Guide (accessed 2026-07-24)Earliest/latest sowing dates for a May 1 last-frost / Oct 1 first-frost baseline; offsets derived by date difference from May 1. Also days-to-maturity figures.