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When to Plant Komatsuna in Washington County, NE

Washington County, Nebraska Zone 5b May

May in Washington County, Nebraska — your action list

Each item below is timed to Washington County, Nebraska's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 23
Avg. first frost October 11
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Fire up the seed-starting tray: komatsuna

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Harvest komatsuna as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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.

Washington County, Nebraska is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.

At an elevation of 508 feet, Washington County receives approximately 29.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Komatsuna during the growing season.

Washington County, NE (Zone 5b) Moderate season
171 days
Last Spring Frost April 23
171 growing days
First Fall Frost October 11
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Washington County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: May 25 – Jun 29
Recommended (50%) ✓ Fits season (101 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jul 2
Safe Start (90%) ✓ Fits season (95 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 15 – Jul 20

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 Washington County

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

Soil pH

Your soil pH (6.8–7.6) overlaps with Komatsuna's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Komatsuna.

Organic Matter

Organic matter is excellent (4.2%) — Komatsuna will thrive.

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

5
successive plantings in your 171-day season

Sow every 4 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 02.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,051 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 0.9" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Washington 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 ~584 GDD — county provides 2,351 GDD Excellent fit

Komatsuna Planting Timeline — Washington County, NE

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 9 Apr 9 – Apr 30
Harvest May 28 May 28 – Jul 2
Fall Sowing August 2 Aug 2 – Aug 16

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Harvest
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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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 5b

📆 Growing Season

171 days in Washington County

Growing Tips for Komatsuna in Washington County

Direct sow Komatsuna outdoors after April 23 in Washington County when soil has warmed and frost danger has passed.

Your generous 171.0-day season in Washington 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 Washington County, NE?

Washington County is in Zone 5b with an average last frost of April 23. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, NE?

Washington County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 11.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington 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 Washington County, NE. 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.