When to plant eggplant 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 eggplant 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
Mar 15 – Mar 29Sow 8–10 weeks before the transplant window opens (UNH 8–10 weeks; Missouri G6570 6–8 weeks). Anchored to the median last spring freeze (May 10). University of New Hampshire Extension · University of Missouri Extension
Transplant outdoors
May 24 – Jun 7UNH: set out 2–3 weeks after the last frost; Purdue: very tender — at least two weeks after. Span extended to 14 days. Anchored to the median last spring freeze (May 10). University of New Hampshire Extension · Purdue University Extension
Variety assumption: Assumes an average variety (about 65–80 days from transplant).
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 (3)
- 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.