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When to Plant Mizuna in Franklin County, IL

Franklin County, Illinois Zone 7a May

Your May gardening checklist

Your garden in Franklin County, Illinois is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 10
Avg. first frost October 20
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Sow mizuna in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Start harvesting mizuna

    If you can't use it all right away, check the food-preservation section of your planner.

June prep starts now
  • 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.

Franklin County, Illinois is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 20, giving you a growing season of approximately 193 days.

At an elevation of 747 feet, Franklin County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Mizuna during the growing season.

Franklin County, IL (Zone 7a) Moderate season
193 days
Last Spring Frost April 10
193 growing days
First Fall Frost October 20
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Franklin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (127 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: May 11 – Jun 8
Recommended (50%) ✓ Fits season (130 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: May 15 – Jun 12
Safe Start (90%) ✓ Fits season (130 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jun 25

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 Franklin County

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

Soil pH

Your soil pH (5.9–7.1) overlaps with Mizuna's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 193-day season

Sow every 3.4 weeks. Last sowing by Sep 05 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

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 388 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Franklin 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 ~628 GDD — county provides 3,232 GDD Excellent fit

Mizuna Planting Timeline — Franklin County, IL

Mizuna Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors April 10 Apr 10 – Apr 24
Direct Sow March 27 Mar 27 – Apr 17
Harvest May 15 May 15 – Jun 12
Fall Sowing August 11 Aug 11 – Aug 25

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May 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 7a

📆 Growing Season

193 days in Franklin County

Growing Tips for Mizuna in Franklin County

Direct sow Mizuna outdoors after April 10 in Franklin County when soil has warmed and frost danger has passed.

Your generous 193.0-day season in Franklin 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 Franklin County, IL?

Franklin County is in Zone 7a with an average last frost of April 10. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Franklin County, IL?

Franklin County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 20.

🌱

Your Franklin County Garden Planner — Free

A 24-page printable planner built for Franklin County (Zone 7a). 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 Franklin County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

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