When to Plant Napa Cabbage in Yuma County, CO
Top priorities for Yuma County, Colorado gardeners in May
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Harden off and plant napa cabbage
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
Looking ahead to June
- Starting indoors: napa cabbage
Napa cabbage forms tall, barrel-shaped heads with tender, crinkled leaves and a mild, slightly sweet flavor. It is the primary cabbage used for kimchi.
Yuma County, Colorado is in USDA Zone 5b. The average last spring frost is May 11 and the first fall frost is October 5, giving you a growing season of approximately 147 days.
At an elevation of 7,664 feet, Yuma County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Napa Cabbage during the growing season.
Yuma County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.9
Drainage
Well Drained
Plant Planting Risk Windows
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 Yuma County
How your county's soil matches Napa Cabbage's growing requirements.
Soil pH
Your soil pH (6.6–7.9) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Yuma County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Napa Cabbage.
How to Plant Napa Cabbage
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Napa Cabbage
Sow every 6.3 weeks. Last sowing by Jul 22 to harvest before frost.
For a dedicated fall crop, sow by Jul 27.
Plant Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Napa Cabbage
Napa Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Napa Cabbage Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 6.5" | 2.3" | 4.2" | 🚿 Regular watering |
| Jun | 6.5" | 1.4" | 5.1" | 🚿 Regular watering |
| Jul | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Aug | 6.5" | 2.2" | 4.3" | 🚿 Regular watering |
| Sep | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Oct | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Yuma County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Napa 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.
Napa Cabbage Planting Timeline — Yuma County, CO
Napa Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 6 | Apr 6 – Apr 20 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | April 27 | Apr 27 – May 18 |
| Harvest | July 6 | Jul 6 – Aug 10 |
| Fall Sowing | July 27 | Jul 27 – Aug 10 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
55–75 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
147 days in Yuma County
Growing Tips for Napa Cabbage in Yuma County
Direct sow Napa Cabbage outdoors after May 11 in Yuma County when soil has warmed and frost danger has passed.
Common pests for Napa Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
Yuma County receives only 20" of rain annually. Napa Cabbage needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Best grown as a fall crop. Direct sow in late summer, 60-70 days before first frost. Keep soil evenly moist. Bolt-resistant varieties are available for spring planting.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Napa Cabbage in Other Locations
Frequently Asked Questions
When should I plant Napa Cabbage in Yuma County, CO?
Yuma County is in Zone 5b with an average last frost of May 11. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yuma County, CO?
Yuma County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 11 and first fall frost is October 5.
Your Yuma County Garden Planner — Free
A 24-page printable planner built for Yuma 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.