Conditional — Some Areas
broccoli (zones 2-11) has limited zone overlap with Iowa (4b-5b). Only zones 4-5 in the state are suitable.
Zone Comparison
Broccoli Needs
- USDA Zones: 2-11
- Soil pH: 5.5 - 8.5
- Sun: Part Sun
- Drainage: well (dry spells)
- Frost-Free Days: 60+
Iowa Has
- USDA Zones: 4b-5b
- Last Frost: Apr 20 - May 15
- First Frost: Sep 25 - Oct 15
- Annual Rainfall: 26-36 inches
- Common Soils: Prairie loess, Silt loam, Clay loam
Plant Zone Range (zones 2-11)
Preferred Soil pH
Plant data: USDA PLANTS Database / plant_species_v5.csv. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
Growing Season Fit
Zone compatibility says you can survive winter here. Whether the growing season is long enough — and warm enough — is a different question.
Frost-free days
Broccoli wants 60+ frost-free days; a typical Iowa site sees ~170 (NOAA Climate Normals). That leaves comfortable headroom for succession planting.
Growing degree days
Broccoli needs ~1500 GDD (base 50°F) to ripen. The state median runs ~2900 GDD (USDA NRCS county aggregates), so Iowa's typical season clears that easily.
Climate aggregates derive from USDA NRCS county-level hardiness data + Cornell CALS Extension GDD-by-region tables + MSU Extension chill-hours-by-zone (1991-2020 NOAA Climate Normals baseline).
Soil + Drainage Fit
Broccoli likes near-neutral soil (pH 5.5-8.5). That's the common-ground band across Iowa's prairie loess and silt loam — a soil test confirms it for your site. Drainage matters: this plant wants well (dry spells). If your Iowa site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH and drainage requirements from USDA PLANTS Database. Iowa soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Broccoli in Iowa — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 2-11 (USDA PLANTS Database)
- State Zones: 4b-5b (USDA ARS PHZM 2023)
- Growing Season: Apr 20 - May 15 to Sep 25 - Oct 15 (NOAA Climate Normals)
- Days to Maturity: 70 days
What Else to Consider
Zone compatibility tells you about winter cold survival — but Iowa growers also need to think about:
Cold winters reaching -20F or below
Variable spring weather delays planting
Wind exposure on open prairies desiccates plants
Pollinator + Wildlife Value
Broccoli draws pollinators (moderate value, USDA PLANTS Database). Planting it near vegetable beds can lift fruit set on neighboring crops.
Iowa Cooperative Extension
For Iowa-specific cultivar recommendations, planting calendars, and pest pressure for broccoli, the canonical source is Iowa State University Extension and Outreach. Their fact sheets carry the local trial data we can't generalize across 50 states.
Check your specific parcel in Iowa
State-level data is a sketch. Your Growable Ground report scores broccoli against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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