Blog

When to plant Cabbage in Washington County, CO

Aim to plant Cabbage in Washington County on or after April 26; the window stays open through May 17. Washington County's 148-day frost-free season gives you a single solid spring crop with a brief fall option. A second sowing from July 27 to August 10 extends the harvest into fall.

When to Plant Cabbage in Washington County, CO

Cabbage
Washington County, Colorado Zone 5b June

June in the garden — Washington County, Colorado

We've pulled the most time-sensitive tasks for Washington County, Colorado this June and put them front and centre. Tackle them in order.

Avg. last frost May 10
Avg. first frost October 5
Soil temp (4") 53°F
Watering Critical
Pest pressure High
Daylight 14.8 hrs
  1. Start cabbage under lights

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

A few tasks this June that'll pay off in July
  • First harvests: cabbage
  • Fall sowing: cabbage

Instant PDF download. No spam, unsubscribe any time.

Cabbage is a versatile cool-season crop that forms dense, leafy heads in green, red, or savoy varieties. It is a staple for coleslaw, sauerkraut, and many global cuisines.

Washington County, Colorado is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 6,091 feet, Washington County receives approximately 13 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Cabbage during the growing season. With low rainfall, drip irrigation is essential for growing Cabbage successfully. Mulch heavily to conserve soil moisture.

Washington County, CO (Zone 5b) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Washington County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Cabbage Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jul 4 – Aug 29
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 12 – Sep 6
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jul 22 – Sep 16

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 Cabbage's growing requirements.

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Cabbage prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Cabbage.

How to Plant Cabbage

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 Cabbage

2
successive plantings in your 148-day season

Sow every 6.9 weeks. Last sowing by Jun 27 to harvest before frost.

For a dedicated fall crop, sow by Jul 27.

Cabbage Water Budget

Plant needs
0.9″/week
Rainfall provides
0.4″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 839 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Cabbage

Cabbage needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Cabbage Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 3.9" 1.5" 2.4" 🚿 Regular watering
Jun 3.9" 1" 2.9" 🚿 Regular watering
Jul 3.9" 1.2" 2.7" 🚿 Regular watering
Aug 3.9" 1.5" 2.4" 🚿 Regular watering
Sep 3.9" 1.1" 2.8" 🚿 Regular watering
Oct 3.9" 1.1" 2.8" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Cabbage 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.

Cabbage needs ~1,100 GDD — county provides 2,035 GDD Excellent fit

Cabbage Planting Timeline — Washington County, CO

Cabbage Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 10 May 10 – May 24
Direct Sow April 26 Apr 26 – May 17
Harvest July 12 Jul 12 – Sep 6
Fall Sowing July 27 Jul 27 – Aug 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 1-2 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Washington County

Growing Tips for Cabbage in Washington County

Direct sow Cabbage outdoors after May 10 in Washington County when soil has warmed and frost danger has passed.

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

Washington County receives only 13" of rain annually. Cabbage needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 4-6 weeks before last frost. Space plants 18-24 inches apart. Keep soil evenly moist to prevent heads from splitting.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries
  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cabbage in Washington County, CO?

Washington County is in Zone 5b with an average last frost of May 10. Plan your Cabbage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, CO?

Washington County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 5.

When should I plant Cabbage in Washington County, CO?

In Washington County, CO, plant Cabbage after the last frost (around May 10) and before the first frost (around October 5). Best results when soil holds above 50°F.

What growing zone is Washington County, CO for Cabbage?

Washington County sits in USDA Zone 5b. Cabbage grows reliably in zones 1a through 10b, so it's a good fit here.

Can Cabbage grow in Washington County's climate?

Yes — Cabbage grows well in Washington County's temperate climate. Washington County averages a 148-day frost-free season, with last frost around May 10 and first frost around October 5.

🌱

Your Washington County Garden Planner — Free

A 22-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.

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 Washington County, CO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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