Blog

When to Plant Tatsoi in Johnson County, KS

Johnson County, Kansas Zone 6b May

What to do in May

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

Avg. last frost April 8
Avg. first frost October 26
Soil temp (4") 62°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Indoor seed-starting week for tatsoi

    You're about 22 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Bring in the tatsoi

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

June will be here before you know it — start on
  • First harvests: tatsoi

Instant PDF download. No spam, unsubscribe any time.

Tatsoi is a compact Asian green forming beautiful rosettes of dark, spoon-shaped leaves with a mild mustard flavor. It is extremely cold-hardy and versatile.

Johnson County, Kansas is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 26, giving you a growing season of approximately 201 days.

At an elevation of 768 feet, Johnson County receives approximately 27.6 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Tatsoi during the growing season.

Johnson County, KS (Zone 6b) Long season
201 days
Last Spring Frost April 8
201 growing days
First Fall Frost October 26
Share this guide:

Johnson County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (131 days to spare)
Start indoors: Feb 28 Transplant: Apr 4 🍅 Harvest: May 9 – Jun 13
Recommended (50%) ✓ Fits season (131 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🍅 Harvest: May 13 – Jun 17
Safe Start (90%) ✓ Fits season (135 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jul 2

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 Johnson County

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

Soil pH

Your soil pH (6.8–7.2) is within Tatsoi's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

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

How to Plant Tatsoi

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 Tatsoi

6
successive plantings in your 201-day season

Sow every 4 weeks. Last sowing by Sep 06 to harvest before frost.

For a dedicated fall crop, sow by Aug 17.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 909 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Tatsoi

Tatsoi needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Tatsoi Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Johnson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Tatsoi 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.

Tatsoi needs ~648 GDD — county provides 3,065 GDD Excellent fit

Tatsoi Planting Timeline — Johnson County, KS

Tatsoi Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow March 25 Mar 25 – Apr 15
Harvest May 13 May 13 – Jun 17
Fall Sowing August 17 Aug 17 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July
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: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

201 days in Johnson County

Growing Tips for Tatsoi in Johnson County

Direct sow Tatsoi outdoors after April 08 in Johnson County when soil has warmed and frost danger has passed.

Your generous 201.0-day season in Johnson County allows multiple plantings of Tatsoi. Sow every 17.0 days for continuous harvest.

Common pests for Tatsoi 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. Tatsoi tolerates frost down to 15F. Harvest outer leaves or cut whole rosettes. Excellent in salads, stir-fries, or lightly wilted.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tatsoi in Johnson County, KS?

Johnson County is in Zone 6b with an average last frost of April 8. Plan your Tatsoi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnson County, KS?

Johnson County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 26.

🌱

Your Johnson County Garden Planner — Free

A 24-page printable planner built for Johnson County (Zone 6b). 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 Johnson County, KS. 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.