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When to Plant Tatsoi in Park County, CO

Park County, Colorado Zone 5b May

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

May is a pivotal month for Park County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 16
Avg. first frost September 4
Soil temp (4") 34°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
June will be here before you know it — start on
  • Transplants going out: tatsoi
  • Direct-sowing: tatsoi
  • Fall sowing: tatsoi

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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.

Park County, Colorado is in USDA Zone 5b. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,567 feet, Park County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Tatsoi to ensure they mature before fall.

Park County, CO (Zone 5b) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4
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Park County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Jul 15 – Aug 19
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Jul 21 – Aug 25
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: May 22 Transplant: Jun 26 🍅 Harvest: Jul 31 – Sep 4

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 Park County

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

Soil pH

Your soil pH (6.2–7.6) overlaps with Tatsoi's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Tatsoi.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Tatsoi.

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

2
successive plantings in your 80-day season

Sow every 4 weeks. Last sowing by Jul 16 to harvest before frost.

For a dedicated fall crop, sow by Jun 26.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 66 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 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.1" 0" ❄️ Dormant
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Park 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 ~521 GDD — county provides 980 GDD Excellent fit

Tatsoi Planting Timeline — Park County, CO

Tatsoi Planting Calendar

Activity When Date Range
Start Indoors May 12 May 12 – May 26
Transplant Outdoors June 16 Jun 16 – Jun 30
Direct Sow June 2 Jun 2 – Jun 23
Harvest July 21 Jul 21 – Aug 25
Fall Sowing June 26 Jun 26 – Jul 10

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

Month-by-Month Timeline

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

80 days in Park County

Growing Tips for Tatsoi in Park County

Direct sow Tatsoi outdoors after June 16 in Park County when soil has warmed and frost danger has passed.

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

Park County receives only 23" of rain annually. Tatsoi needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Park County, CO?

Park County is in Zone 5b with an average last frost of June 16. Plan your Tatsoi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, CO?

Park County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 4.

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Your Park County Garden Planner — Free

A 24-page printable planner built for Park 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 Park 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.