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When to Plant Mizuna in Fayette County, IA

Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.

Fayette County, Iowa is in USDA Zone 4b. The average last spring frost is May 5 and the first fall frost is October 5, giving you a growing season of approximately 153 days.

At an elevation of 1,228 feet, Fayette County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Mizuna to ensure they mature before fall.

Fayette County, IA (Zone 4b) Moderate season
153 days
Last Spring Frost May 5
153 growing days
First Fall Frost October 5

Fayette County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🍅 Harvest: Jun 2 – Jun 30
Recommended (50%) ✓ Fits season (90 days to spare)
Start indoors: Mar 24 Transplant: May 5 🍅 Harvest: Jun 9 – Jul 7
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Jun 24 – Jul 22

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

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Mizuna needs ~403 GDD — county provides 1,644 GDD Excellent fit

Mizuna Planting Timeline โ€” Fayette County, IA

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 โ€“ Apr 7
Transplant Outdoors May 5 May 5 โ€“ May 19
Direct Sow April 28 Apr 28 โ€“ May 19
Fall Sowing July 13 Jul 13 โ€“ Jul 27
Harvest June 9 Jun 9 โ€“ Jul 7

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

30โ€“45 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

153 days

Growing Tips for Fayette County

Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Mizuna in Fayette County, IA?

Fayette County is in Zone 4b with an average last frost of May 5. Plan your Mizuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Fayette County, IA?

Fayette County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is May 5 and first fall frost is October 5.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Fayette County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Fayette County, IA. Local conditions may vary. Last updated: April 2026.