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When to Plant Komatsuna in Putnam County, IN

Putnam County, Indiana Zone 6a May

What to do in May

A quick May briefing for Putnam County, Indiana gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 14
Avg. first frost October 21
Soil temp (4") 63°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
  1. Begin indoor sowing: komatsuna

    You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Bring in the komatsuna

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

A few tasks this May that'll pay off in June
  • 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.

Putnam County, Indiana is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 21, giving you a growing season of approximately 190 days.

At an elevation of 670 feet, Putnam County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Komatsuna during the growing season.

Putnam County, IN (Zone 6a) Moderate season
190 days
Last Spring Frost April 14
190 growing days
First Fall Frost October 21
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Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 16 – Jun 20
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 19 – Jun 23
Safe Start (90%) ✓ Fits season (113 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jun 7 – Jul 12

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 Putnam County

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

Soil pH

Your soil pH (6.0–7.2) is within Komatsuna's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Komatsuna.

Organic Matter

Organic matter is excellent (4.3%) — 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

6
successive plantings in your 190-day season

Sow every 4 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,025 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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Putnam 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 ~680 GDD — county provides 3,040 GDD Excellent fit

Komatsuna Planting Timeline — Putnam County, IN

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest May 19 May 19 – Jun 23
Fall Sowing August 12 Aug 12 – Aug 26

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 · 1-2 times/week

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

190 days in Putnam County

Growing Tips for Komatsuna in Putnam County

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

Your generous 190.0-day season in Putnam 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 Putnam County, IN?

Putnam County is in Zone 6a with an average last frost of April 14. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Putnam County, IN?

Putnam County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 21.

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Your Putnam County Garden Planner — Free

A 24-page printable planner built for Putnam County (Zone 6a). 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 Putnam County, IN. 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.