Blog

When to Plant Tatsoi in Polk County, WI

Polk County, Wisconsin Zone 4b May

Top priorities for Polk County, Wisconsin gardeners in May

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

Avg. last frost May 12
Avg. first frost September 29
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Move tatsoi from tray to bed

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Sow tatsoi where they'll grow

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

To set up a strong June, finish these tasks
  • Starting indoors: tatsoi
  • 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.

Polk County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is September 29, giving you a growing season of approximately 140 days.

At an elevation of 582 feet, Polk County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Tatsoi to ensure they mature before fall.

Polk County, WI (Zone 4b) Short season
140 days
Last Spring Frost May 12
140 growing days
First Fall Frost September 29

Polk County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (77 days to spare)
Start indoors: Mar 19 Transplant: Apr 30 🍅 Harvest: Jun 4 – Jul 9
Recommended (50%) ✓ Fits season (70 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jun 16 – Jul 21
Safe Start (90%) ✓ Fits season (76 days to spare)
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Jun 24 – Jul 29

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 Polk County

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

Soil pH

Your soil pH (6.0–6.9) is within Tatsoi's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Tatsoi.

How to Plant Tatsoi

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Tatsoi

4
successive plantings in your 140-day season

Sow every 4 weeks. Last sowing by Aug 10 to harvest before frost.

For a dedicated fall crop, sow by Jul 07.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.6" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 2.8" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Polk 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 ~489 GDD — county provides 1,610 GDD Excellent fit

Tatsoi Planting Timeline — Polk County, WI

Tatsoi Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 5 May 5 – May 26
Harvest June 16 Jun 16 – Jul 21
Fall Sowing July 7 Jul 7 – Jul 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

140 days in Polk County

Growing Tips for Tatsoi in Polk County

Direct sow Tatsoi outdoors after May 12 in Polk County when soil has warmed and frost danger has passed.

Your generous 140.0-day season in Polk 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 Polk County, WI?

Polk County is in Zone 4b with an average last frost of May 12. Plan your Tatsoi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Polk County, WI?

Polk County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is September 29.

🌱

Your Polk County Garden Planner — Free

A 24-page printable planner built for Polk County (Zone 4b). 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 Polk County, WI. 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.