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When to Plant Komatsuna in Pitkin 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.

Pitkin County, Colorado is in USDA Zone 4a. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.

At an elevation of 6,411 feet, Pitkin County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Komatsuna to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Komatsuna successfully. Mulch heavily to conserve soil moisture.

Pitkin County, CO (Zone 4a) Very short season
83 days
Last Spring Frost June 16
83 growing days
First Fall Frost September 7

Pitkin County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Apr 24 Transplant: Jun 5 🍅 Harvest: Jul 10 – Aug 14
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: May 5 Transplant: Jun 16 🍅 Harvest: Jul 21 – Aug 25
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: May 16 Transplant: Jun 27 🍅 Harvest: Aug 1 – Sep 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 88 gal / 100 sq ft
Drought risk

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

Komatsuna needs ~489 GDD — county provides 954 GDD Excellent fit

Komatsuna Planting Timeline โ€” Pitkin County, CO

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors May 5 May 5 โ€“ May 19
Transplant Outdoors June 16 Jun 16 โ€“ Jun 30
Direct Sow June 9 Jun 9 โ€“ Jun 30
Fall Sowing June 15 Jun 15 โ€“ Jun 29
Harvest July 21 Jul 21 โ€“ Aug 25

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
June Transplant Outdoors Direct Sow Fall Sowing
July 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 4a

Growing Season

83 days

Growing Tips for Pitkin 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 Pitkin County, CO?

Pitkin County is in Zone 4a with an average last frost of June 16. Plan your Komatsuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pitkin County, CO?

Pitkin County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 16 and first fall frost is September 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pitkin County gardeners in Zone 4a 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 Pitkin County, CO. Local conditions may vary. Last updated: April 2026.