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When to Plant Komatsuna in Montrose County, CO

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.

Montrose County, Colorado is in USDA Zone 6a. The average last spring frost is June 13 and the first fall frost is September 12, giving you a growing season of approximately 91 days.

At an elevation of 6,494 feet, Montrose County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Komatsuna during the growing season. With low rainfall, drip irrigation is essential for growing Komatsuna successfully. Mulch heavily to conserve soil moisture.

Montrose County, CO (Zone 6a) Very short season
91 days
Last Spring Frost June 13
91 growing days
First Fall Frost September 12

Montrose County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jun 18 – Jul 23
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: May 9 Transplant: Jun 13 🍅 Harvest: Jul 18 – Aug 22
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: May 22 Transplant: Jun 26 🍅 Harvest: Jul 31 – Sep 4

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 147 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Komatsuna needs ~648 GDD — county provides 1,387 GDD Excellent fit

Komatsuna Planting Timeline โ€” Montrose County, CO

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors May 9 May 9 โ€“ May 23
Transplant Outdoors June 13 Jun 13 โ€“ Jun 27
Direct Sow May 30 May 30 โ€“ Jun 20
Fall Sowing July 4 Jul 4 โ€“ Jul 18
Harvest July 18 Jul 18 โ€“ Aug 22

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

35โ€“50 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6a

Growing Season

91 days

Growing Tips for Montrose County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Komatsuna in Montrose County, CO?

Montrose County is in Zone 6a with an average last frost of June 13. Plan your Komatsuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Montrose County, CO?

Montrose County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is June 13 and first fall frost is September 12.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Montrose County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Montrose County, CO. Local conditions may vary. Last updated: April 2026.