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When to plant Kale in Washington County, MN

Plant Kale in Washington County after April 23; the prime window is April 9–April 30. A second sowing from July 31 to August 14 extends the harvest into fall.

When to Plant Kale in Washington County, MN

Kale
Washington County, Minnesota Zone 5a August

Top priorities for Washington County, Minnesota gardeners in August

If you only do a handful of things in the garden this August, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 23
Avg. first frost October 9
Soil temp (4") 74°F
Watering Moderate
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for kale

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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Kale is an exceptionally hardy, nutrient-dense green available in curly, lacinato, and Russian varieties. It tolerates heavy frost and often tastes sweeter after cold exposure.

Washington County, Minnesota is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 9, giving you a growing season of approximately 169 days.

At an elevation of 832 feet, Washington County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Kale during the growing season.

Washington County, MN (Zone 5a) Moderate season
169 days
Last Spring Frost April 23
169 growing days
First Fall Frost October 9

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Kale Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Aug 7
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 13
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 8 – Sep 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 Washington County

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

Soil pH

Your soil pH (5.8–6.9) overlaps with Kale's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Kale will thrive.

How to Plant Kale

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Kale

3
successive plantings in your 169-day season

Sow every 5.7 weeks. Last sowing by Jul 31 to harvest before frost.

For a dedicated fall crop, sow by Jul 31.

Kale Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 63 gal / 100 sq ft

Monthly Watering Guide for Kale

Kale needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Kale Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.5" 3" 0.5" 💧 Light watering
May 3.5" 3.4" 0.1" 💧 Light watering
Jun 3.5" 4.1" 0" ✅ Rainfall sufficient
Jul 3.5" 3.1" 0.4" 💧 Light watering
Aug 3.5" 3.3" 0.2" 💧 Light watering
Sep 3.5" 2.4" 1.1" 💧 Light watering
Oct 3.5" 2.4" 1.1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.5" 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.

Kale 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.

Kale needs ~825 GDD — county provides 2,323 GDD Excellent fit

Kale Planting Timeline — Washington County, MN

Kale 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 June 18 Jun 18 – Aug 13
Fall Sowing July 31 Jul 31 – Aug 14

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

169 days in Washington County

Growing Tips for Kale in Washington County

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

Common pests for Kale 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 or transplant in early spring or late summer. Harvest outer leaves first to keep plants productive. Kale overwinters in many climates and can provide greens all year.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Kale Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow 2nd year flower stalks to dry. Harvest pods when tan.
Storage Store airtight; viable 5 years at 35°F, under 50% humidity.

Isolate 1/2 mile from other brassicas (broccoli, cabbage, etc.) — they all cross.

Frequently Asked Questions

When should I plant Kale in Washington County, MN?

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

What planting zone is Washington County, MN?

Washington County, Minnesota is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 9.

When should I plant Kale in Washington County, MN?

In Washington County, MN, plant Kale after the last frost (around April 23) and before the first frost (around October 9). Best results when soil holds above 50°F.

What growing zone is Washington County, MN for Kale?

Washington County sits in USDA Zone 5a. Kale grows reliably in zones 2a through 11b, so it's a good fit here.

Can Kale grow in Washington County's climate?

Yes — Kale grows well in Washington County's temperate climate. Washington County averages a 169-day frost-free season, with last frost around April 23 and first frost around October 9.

🌱

Your Washington County Garden Planner — Free

A 22-page printable planner built for Washington County (Zone 5a). 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, MN. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.