When to Plant Romanesco in Iowa County, WI
Romanesco is a stunning brassica with a lime-green head composed of fractal-patterned spiraling florets. It has a nuttier, milder flavor than cauliflower.
Iowa County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.
At an elevation of 602 feet, Iowa County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Romanesco to ensure they mature before fall.
Iowa County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-7.1
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Plant Water Budget
Romanesco Planting Timeline — Iowa County, WI
Romanesco Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 22 | Mar 22 – Apr 5 |
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Direct Sow | April 26 | Apr 26 – May 17 |
| Fall Sowing | July 15 | Jul 15 – Jul 29 |
| Harvest | July 19 | Jul 19 – Aug 30 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
75–100 days
Soil pH
6 – 7
USDA Zone
Zone 4b
Growing Season
157 days
Growing Tips for Iowa County
Start seeds indoors 5-7 weeks before transplanting. Provide consistent moisture and avoid temperature stress. Harvest when head is fully formed but before florets begin to separate.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Romanesco in Other Locations
Frequently Asked Questions
When should I plant Romanesco in Iowa County, WI?
Iowa County is in Zone 4b with an average last frost of May 3. Plan your Romanesco planting based on this frost date — see the calendar above for exact timing.
What planting zone is Iowa County, WI?
Iowa County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Iowa County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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