When to plant beets in Denver, Colorado
April 2 – April 16
Direct-sow 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. Direct-sow beets 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
Direct-sow outdoors
Apr 2 – Apr 16Purdue: semi-hardy — 2–4 weeks before the last frost. Penn State sows from Apr 1 (−30) and UNH keys to 45°F soil; the later Purdue range is used. Anchored to the median last spring freeze (Apr 30). Purdue University Extension · Penn State Extension (York County Master Gardeners) · University of New Hampshire Extension
Fall planting
Aug 17 – Sep 14Purdue Table 2: plant fall beets at least 4–8 weeks before the first fall frost, allowing for days to maturity. Anchored to the median first fall freeze (Oct 12). Purdue University Extension
Variety assumption: Assumes an average round variety (about 55–70 days; 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 (3)
- 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.
- 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.