Blog

When to Plant Komatsuna in Hardeman County, TN

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.

Hardeman County, Tennessee is in USDA Zone 7b. The average last spring frost is March 30 and the first fall frost is October 30, giving you a growing season of approximately 214 days.

At an elevation of 3,185 feet, Hardeman County receives approximately 48.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92ยฐF, providing good warmth for Komatsuna during the growing season.

Hardeman County, TN (Zone 7b) Long season
214 days
Last Spring Frost March 30
214 growing days
First Fall Frost October 30

Hardeman County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (145 days to spare)
Start indoors: Feb 17 Transplant: Mar 24 🍅 Harvest: Apr 28 – Jun 2
Recommended (50%) ✓ Fits season (144 days to spare)
Start indoors: Feb 23 Transplant: Mar 30 🍅 Harvest: May 4 – Jun 8
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: May 21 – 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 Hardeman County

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

Soil pH

Your soil pH (5.2โ€“6.5) is more acidic than Komatsuna prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Hardeman County is excellent for Komatsuna โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Komatsuna.

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

7
successive plantings in your 214-day season

Sow every 4 weeks. Last sowing by Sep 10 to harvest before frost.

For a dedicated fall crop, sow by Aug 21.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 88 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 โ€” 3.5" 0" โ„๏ธ Dormant
Feb โ€” 4.1" 0" โ„๏ธ Dormant
Mar 4.3" 5.2" 0" โœ… Rainfall sufficient
Apr 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
May 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Jun 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Jul 4.3" 5" 0" โœ… Rainfall sufficient
Aug 4.3" 4.6" 0" โœ… Rainfall sufficient
Sep 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Oct 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Nov โ€” 3.7" 0" โ„๏ธ Dormant
Dec โ€” 4.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Oct in Hardeman County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~808 GDD — county provides 4,066 GDD Excellent fit

Komatsuna Planting Timeline โ€” Hardeman County, TN

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 โ€“ Mar 9
Transplant Outdoors March 30 Mar 30 โ€“ Apr 13
Direct Sow March 16 Mar 16 โ€“ Apr 6
Harvest May 4 May 4 โ€“ Jun 8
Fall Sowing August 21 Aug 21 โ€“ Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

35โ€“50 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

214 days in Hardeman County

Growing Tips for Komatsuna in Hardeman County

Direct sow Komatsuna outdoors after March 30 in Hardeman County when soil has warmed and frost danger has passed.

Your generous 214.0-day season in Hardeman 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 Hardeman County, TN?

Hardeman County is in Zone 7b with an average last frost of March 30. Plan your Komatsuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Hardeman County, TN?

Hardeman County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is March 30 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Hardeman County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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