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When to Plant Komatsuna in Cumberland County, TN

Cumberland County, Tennessee Zone 7a May

May in Cumberland County, Tennessee — your action list

May is a pivotal month for Cumberland County, Tennessee gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 15
Avg. first frost October 23
Soil temp (4") 60°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Sow komatsuna in trays indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Bring in the komatsuna

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Get ahead of 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.

Cumberland County, Tennessee is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 23, giving you a growing season of approximately 191 days.

At an elevation of 3,392 feet, Cumberland County receives approximately 50.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Komatsuna during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Komatsuna root diseases.

Cumberland County, TN (Zone 7a) Moderate season
191 days
Last Spring Frost April 15
191 growing days
First Fall Frost October 23

Cumberland County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (122 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 13 – Jun 17
Recommended (50%) ✓ Fits season (121 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: May 20 – Jun 24
Safe Start (90%) ✓ Fits season (118 days to spare)
Start indoors: Mar 25 Transplant: Apr 29 🍅 Harvest: Jun 3 – Jul 8

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 Cumberland County

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

Soil pH

Your soil pH (5.5–7.0) overlaps with Komatsuna's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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

6
successive plantings in your 191-day season

Sow every 4 weeks. Last sowing by Sep 03 to harvest before frost.

For a dedicated fall crop, sow by Aug 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/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 4.3" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 5.5" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.4" 0" ✅ Rainfall sufficient
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 4.3" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cumberland 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 ~871 GDD — county provides 3,915 GDD Excellent fit

Komatsuna Planting Timeline — Cumberland County, TN

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest May 20 May 20 – Jun 24
Fall Sowing August 14 Aug 14 – Aug 28

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 Harvest
June Harvest
July
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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

191 days in Cumberland County

Growing Tips for Komatsuna in Cumberland County

Direct sow Komatsuna outdoors after April 15 in Cumberland County when soil has warmed and frost danger has passed.

Your generous 191.0-day season in Cumberland 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 Cumberland County, TN?

Cumberland County is in Zone 7a with an average last frost of April 15. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cumberland County, TN?

Cumberland County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 23.

🌱

Your Cumberland County Garden Planner — Free

A 24-page printable planner built for Cumberland 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Cumberland County, TN. 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.