When to plant spinach in Des Moines, Iowa
March 7 – March 28
Transplant outdoors · typical Des Moines yearClimate basis: NOAA station Des Moines INTL AP, IA (USW00014933), 4 mi (6 km) from downtown Des Moines (ZCTA 50309 centroid), elevation 957 ft, on the 1991–2020 climate normals. Transplant spinach outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (April 18). One year in ten still freezes after May 2.
The Des Moines year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 2
Every method, with its sources
Transplant outdoors
Mar 7 – Mar 28UNH: safe to set out 3–6 weeks before the last frost. Anchored to the median last spring freeze (Apr 18). University of New Hampshire Extension
Direct-sow outdoors
Mar 19 – Apr 2Purdue: hardy — 4–6 weeks before the last frost; Penn State's earliest sowing Apr 1 (−30 days) is the later start and is used. Anchored to the median last spring freeze (Apr 18). Penn State Extension (York County Master Gardeners) · Purdue University Extension
Fall planting
Aug 25 – Sep 22Purdue Table 2: plant fall spinach at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Oct 20). Purdue University Extension
Variety assumption: Assumes an average savoy/smooth variety (about 40–50 days; Penn State lists 50).
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)
- 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.
- 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.
- 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.