Blog

When to Plant Komatsuna in Wasatch County, UT

Wasatch County, Utah Zone 6a May

What to do in May

A quick May briefing for Wasatch County, Utah gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 19
Avg. first frost September 26
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Move komatsuna from tray to bed

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Sow komatsuna where they'll grow

    Your soil is 35°F — warm enough for these to germinate without babying.

To set up a strong June, finish these tasks
  • Starting indoors: komatsuna
  • First harvests: komatsuna

Instant PDF download. No spam, unsubscribe any time.

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.

Wasatch County, Utah is in USDA Zone 6a. The average last spring frost is May 19 and the first fall frost is September 26, giving you a growing season of approximately 130 days.

At an elevation of 8,190 feet, Wasatch County receives approximately 16.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, 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.

Wasatch County, UT (Zone 6a) Short season
130 days
Last Spring Frost May 19
130 growing days
First Fall Frost September 26
Share this guide:

Wasatch County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jun 8 – Jul 13
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Jun 23 – Jul 28
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: May 15 Transplant: Jun 19 🍅 Harvest: Jul 24 – Aug 28

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 Wasatch County

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

Soil pH

Your soil pH (6.6–7.6) overlaps with Komatsuna's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Wasatch County is excellent for Komatsuna — 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

4
successive plantings in your 130-day season

Sow every 4 weeks. Last sowing by Aug 07 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 644 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.2" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 4.3" 2.1" 2.2" 🚿 Regular watering
Jun 4.3" 1.2" 3.1" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.7" 2.6" 🚿 Regular watering
Sep 4.3" 1.2" 3.1" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Wasatch 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 ~616 GDD — county provides 1,885 GDD Excellent fit

Komatsuna Planting Timeline — Wasatch County, UT

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 – Apr 28
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 5 May 5 – May 26
Harvest June 23 Jun 23 – Jul 28
Fall Sowing July 18 Jul 18 – Aug 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

130 days in Wasatch County

Growing Tips for Komatsuna in Wasatch County

Direct sow Komatsuna outdoors after May 19 in Wasatch County when soil has warmed and frost danger has passed.

Your generous 130.0-day season in Wasatch 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.

Wasatch County receives only 17" 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 Wasatch County, UT?

Wasatch County is in Zone 6a with an average last frost of May 19. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wasatch County, UT?

Wasatch County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 19 and first fall frost is September 26.

🌱

Your Wasatch County Garden Planner — Free

A 24-page printable planner built for Wasatch County (Zone 6a). 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 Wasatch County, UT. 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.