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When to Plant Mizuna in Muscatine County, IA

Muscatine County, Iowa Zone 5b April

April in Muscatine County, Iowa — your action list

If you only do a handful of things in the garden this April, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 17
Avg. first frost October 16
Soil temp (4") 44°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
  1. Get mizuna in the ground

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Outdoor sowing time: mizuna

    These tolerate cool soil, so you're not gambling by sowing now.

A few tasks this April that'll pay off in May
  • Starting indoors: mizuna
  • First harvests: mizuna

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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.

Muscatine County, Iowa is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 898 feet, Muscatine County receives approximately 34.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Mizuna to ensure they mature before fall.

Muscatine County, IA (Zone 5b) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16
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Muscatine County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 17 – Jun 14
Recommended (50%) ✓ Fits season (119 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: May 22 – Jun 19
Safe Start (90%) ✓ Fits season (115 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jun 12 – Jul 10

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.

Soil Compatibility in Muscatine County

How your county's soil matches Mizuna's growing requirements.

Soil pH

Your soil pH (5.9–7.0) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Muscatine County is excellent for Mizuna — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) — Mizuna will thrive.

How to Plant Mizuna

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

7
successive plantings in your 182-day season

Sow every 3.4 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 07.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 319 gal / 100 sq ft

Monthly Watering Guide for Mizuna

Mizuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Mizuna Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Muscatine County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mizuna Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Mizuna needs ~459 GDD — county provides 2,229 GDD Excellent fit

Mizuna Planting Timeline — Muscatine County, IA

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 3 Apr 3 – Apr 24
Harvest May 22 May 22 – Jun 19
Fall Sowing August 7 Aug 7 – Aug 21

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

30–45 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

182 days in Muscatine County

Growing Tips for Mizuna in Muscatine County

Direct sow Mizuna outdoors after April 17 in Muscatine County when soil has warmed and frost danger has passed.

Your generous 182.0-day season in Muscatine County allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.

Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mizuna in Muscatine County, IA?

Muscatine County is in Zone 5b with an average last frost of April 17. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Muscatine County, IA?

Muscatine County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 16.

🌱

Your Muscatine County Garden Planner — Free

A 24-page printable planner built for Muscatine County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Muscatine County, IA. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.