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When to Plant Komatsuna in Schoolcraft County, MI

Schoolcraft County, Michigan Zone 5a May

Your May gardening checklist

Each item below is timed to Schoolcraft County, Michigan's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 14
Avg. first frost October 12
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Time to transplant komatsuna

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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

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Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.

Schoolcraft County, Michigan is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is October 12, giving you a growing season of approximately 151 days.

At an elevation of 1,121 feet, Schoolcraft County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Komatsuna to ensure they mature before fall.

Schoolcraft County, MI (Zone 5a) Moderate season
151 days
Last Spring Frost May 14
151 growing days
First Fall Frost October 12

Schoolcraft County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (81 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jun 11 – Jul 16
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jun 18 – Jul 23
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Apr 22 Transplant: May 27 🍅 Harvest: Jul 1 – Aug 5

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 Schoolcraft County

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

Soil pH

Your soil pH (6.0–7.0) is within Komatsuna's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Komatsuna will thrive.

How to Plant Komatsuna

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 Komatsuna

5
successive plantings in your 151-day season

Sow every 4 weeks. Last sowing by Aug 23 to harvest before frost.

For a dedicated fall crop, sow by Aug 03.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Komatsuna

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

Month Komatsuna Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

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

Komatsuna 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.

Komatsuna needs ~489 GDD — county provides 1,736 GDD Excellent fit

Komatsuna Planting Timeline — Schoolcraft County, MI

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors May 14 May 14 – May 28
Direct Sow April 30 Apr 30 – May 21
Harvest June 18 Jun 18 – Jul 23
Fall Sowing August 3 Aug 3 – Aug 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

151 days in Schoolcraft County

Growing Tips for Komatsuna in Schoolcraft County

Direct sow Komatsuna outdoors after May 14 in Schoolcraft County when soil has warmed and frost danger has passed.

Your generous 151.0-day season in Schoolcraft County allows multiple plantings of Komatsuna. Sow every 17.0 days for continuous harvest.

Common pests for Komatsuna 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. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Komatsuna in Schoolcraft County, MI?

Schoolcraft County is in Zone 5a with an average last frost of May 14. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Schoolcraft County, MI?

Schoolcraft County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is October 12.

🌱

Your Schoolcraft County Garden Planner — Free

A 24-page printable planner built for Schoolcraft County (Zone 5a). 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 Schoolcraft County, MI. 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.