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When to Plant Komatsuna in Saguache County, CO

Saguache County, Colorado Zone 5b May

Saguache County, Colorado gardeners: here's your May plan

We've pulled the most time-sensitive tasks for Saguache County, Colorado this May and put them front and centre. Tackle them in order.

Avg. last frost May 30
Avg. first frost September 20
Soil temp (4") 42°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Move komatsuna into the garden

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Seed komatsuna outdoors

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

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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.

Saguache County, Colorado is in USDA Zone 5b. The average last spring frost is May 30 and the first fall frost is September 20, giving you a growing season of approximately 113 days.

At an elevation of 5,293 feet, Saguache County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Komatsuna to ensure they mature before fall.

Saguache County, CO (Zone 5b) Short season
113 days
Last Spring Frost May 30
113 growing days
First Fall Frost September 20

Saguache County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Apr 19 Transplant: May 24 🍅 Harvest: Jun 28 – Aug 2
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Jul 4 – Aug 8
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: May 10 Transplant: Jun 14 🍅 Harvest: Jul 19 – Aug 23

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 Saguache County

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

Soil pH

Your soil pH (6.4–8.4) overlaps with Komatsuna's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Saguache 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

3
successive plantings in your 113-day season

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

For a dedicated fall crop, sow by Jul 12.

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 144 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Saguache 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 ~425 GDD — county provides 1,130 GDD Excellent fit

Komatsuna Planting Timeline — Saguache County, CO

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 16 May 16 – Jun 6
Harvest July 4 Jul 4 – Aug 8
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

113 days in Saguache County

Growing Tips for Komatsuna in Saguache County

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

Common pests for Komatsuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

Saguache County receives only 24" of rain annually. Komatsuna needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Saguache County, CO?

Saguache County is in Zone 5b with an average last frost of May 30. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Saguache County, CO?

Saguache County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 30 and first fall frost is September 20.

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Your Saguache County Garden Planner — Free

A 24-page printable planner built for Saguache County (Zone 5b). 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 Saguache County, CO. 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.