When to plant eggplant in Denver, Colorado
May 14 – May 28
Transplant outdoors · typical Denver yearClimate basis: NOAA station Denver Water Dept, CO (USC00052223), 2 mi (3 km) from downtown Denver (ZCTA 80202 centroid), elevation 5228 ft, on the 1991–2020 climate normals. Transplant eggplant outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (April 30). One year in ten still freezes after May 13.
The Denver year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 13
Every method, with its sources
Start seeds indoors
Mar 5 – Mar 19Sow 8–10 weeks before the transplant window opens (UNH 8–10 weeks; Missouri G6570 6–8 weeks). Anchored to the median last spring freeze (Apr 30). University of New Hampshire Extension · University of Missouri Extension
Transplant outdoors
May 14 – May 28UNH: 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 (Apr 30). 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.