When to Plant Napa Cabbage in Merced County, CA
May to-do list for Merced County, California
Here's what deserves your attention in Merced County, California this month. Everything below is tailored to Zone 9a and timed around your local frost dates.
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Start harvesting napa cabbage
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
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.
Merced County, California is in USDA Zone 9a. The average last spring frost is February 24 and the first fall frost is November 28, giving you a growing season of approximately 277 days.
At an elevation of 269 feet, Merced County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Napa Cabbage during the growing season. With low rainfall, drip irrigation is essential for growing Napa Cabbage successfully. Mulch heavily to conserve soil moisture.
Merced County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.7
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 Merced County
How your county's soil matches Napa Cabbage's growing requirements.
Soil pH
Your soil pH (6.8–7.7) overlaps with Napa Cabbage's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Merced 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 8 weeks before your first frost date for a fall harvest.
Succession Planting Napa Cabbage
Sow every 6.3 weeks. Last sowing by Sep 14 to harvest before frost.
For a dedicated fall crop, sow by Oct 03.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 4.4" | 0" | ❄️ Dormant |
| Feb | 6.5" | 4" | 2.5" | 💧 Light watering |
| Mar | 6.5" | 2.6" | 3.9" | 🚿 Regular watering |
| Apr | 6.5" | 1.7" | 4.8" | 🚿 Regular watering |
| May | 6.5" | 0.4" | 6.1" | 🚿 Regular watering |
| Jun | 6.5" | 0.1" | 6.4" | 🚿 Regular watering |
| Jul | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Aug | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Sep | 6.5" | 0.2" | 6.3" | 🚿 Regular watering |
| Oct | 6.5" | 0.7" | 5.8" | 🚿 Regular watering |
| Nov | 6.5" | 1.6" | 4.9" | 🚿 Regular watering |
| Dec | — | 3.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Merced 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 — Merced County, CA
Napa Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 27 | Jan 27 – Feb 10 |
| Transplant Outdoors | February 24 | Feb 24 – Mar 10 |
| Direct Sow | February 3 | Feb 3 – Feb 24 |
| Harvest | April 21 | Apr 21 – May 26 |
| Fall Sowing | October 3 | Oct 3 – Oct 17 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Transplant Outdoors |
| 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: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
277 days in Merced County
Growing Tips for Napa Cabbage in Merced County
Direct sow Napa Cabbage outdoors after February 24 in Merced 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.
Merced County receives only 19" 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 Merced County, CA?
Merced County is in Zone 9a with an average last frost of February 24. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Merced County, CA?
Merced County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 24 and first fall frost is November 28.
Your Merced County Garden Planner — Free
A 24-page printable planner built for Merced County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.