When to Plant Napa Cabbage in Yuma County, AZ
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, Arizona is in USDA Zone 10a. The average last spring frost is February 10 and the first fall frost is December 1, giving you a growing season of approximately 294 days.
At an elevation of 4,781 feet, Yuma County receives approximately 9.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92°F, providing good warmth for Napa Cabbage during the growing season. Sandy soil warms quickly in spring — great for early planting — but Napa Cabbage will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Napa Cabbage successfully. Mulch heavily to conserve soil moisture.
Yuma County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.9-8.4
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 (6.9–8.4) is more alkaline than Napa Cabbage prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Yuma County warms quickly in spring but drains fast. Napa Cabbage will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (0.8%). Add 2-3 inches of compost before planting Napa Cabbage.
How to Plant Napa Cabbage
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Napa Cabbage
Sow every 6.3 weeks. Last sowing by Sep 17 to harvest before frost.
For a dedicated fall crop, sow by Oct 06.
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 | — | 0.6" | 0" | ❄️ Dormant |
| Feb | 6.5" | 0.5" | 6" | 🚿 Regular watering |
| Mar | 6.5" | 0.5" | 6" | 🚿 Regular watering |
| Apr | 6.5" | 0.3" | 6.2" | 🚿 Regular watering |
| May | 6.5" | 0.2" | 6.3" | 🚿 Regular watering |
| Jun | 6.5" | 0.3" | 6.2" | 🚿 Regular watering |
| Jul | 6.5" | 1.8" | 4.7" | 🚿 Regular watering |
| Aug | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Sep | 6.5" | 1.4" | 5.1" | 🚿 Regular watering |
| Oct | 6.5" | 0.8" | 5.7" | 🚿 Regular watering |
| Nov | 6.5" | 0.5" | 6" | 🚿 Regular watering |
| Dec | 6.5" | 0.6" | 5.9" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec 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, AZ
Napa Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 13 | Jan 13 – Jan 27 |
| Transplant Outdoors | February 10 | Feb 10 – Feb 24 |
| Direct Sow | January 20 | Jan 20 – Feb 10 |
| Harvest | April 7 | Apr 7 – May 12 |
| Fall Sowing | October 6 | Oct 6 – Oct 20 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Direct Sow |
| February | Transplant Outdoors Direct Sow |
| March | — |
| April | Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| 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: too_alkaline
🗺️ USDA Zone
Zone 10a
📆 Growing Season
294 days in Yuma County
Growing Tips for Napa Cabbage in Yuma County
Direct sow Napa Cabbage outdoors after February 10 in Yuma County when soil has warmed and frost danger has passed.
Sandy soil in Yuma County dries quickly — mulch Napa Cabbage with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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 9" 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
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Napa Cabbage in Other Locations
Frequently Asked Questions
When should I plant Napa Cabbage in Yuma County, AZ?
Yuma County is in Zone 10a with an average last frost of February 10. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yuma County, AZ?
Yuma County, Arizona is in USDA Hardiness Zone 10a. The average last spring frost is February 10 and first fall frost is December 1.
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