When to Plant Napa Cabbage in Solano County, CA
What to do in May
Each item below is timed to Solano County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Collect napa cabbage at their peak
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
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.
Solano County, California is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.
At an elevation of 376 feet, Solano County receives approximately 40.4 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Napa Cabbage may need afternoon shade and extra watering during peak heat.
Solano County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.3
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 Solano County
How your county's soil matches Napa Cabbage's growing requirements.
Soil pH
Your soil pH (6.8–7.3) is within Napa Cabbage's preferred range (6.0–7.5).
Soil Texture
The loam soil in Solano County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Napa Cabbage is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.
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 19 to harvest before frost.
For a dedicated fall crop, sow by Oct 08.
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 | — | 8.9" | 0" | ❄️ Dormant |
| Feb | 6.5" | 8.4" | 0" | ✅ Rainfall sufficient |
| Mar | 6.5" | 6.6" | 0" | ✅ Rainfall sufficient |
| Apr | 6.5" | 2.7" | 3.8" | 🚿 Regular watering |
| May | 6.5" | 1" | 5.5" | 🚿 Regular watering |
| Jun | 6.5" | 0.2" | 6.3" | 🚿 Regular watering |
| Jul | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Aug | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Sep | 6.5" | 0.4" | 6.1" | 🚿 Regular watering |
| Oct | 6.5" | 1.9" | 4.6" | 🚿 Regular watering |
| Nov | 6.5" | 3.3" | 3.2" | 💧 Light watering |
| Dec | 6.5" | 7.1" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in Solano 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 — Solano County, CA
Napa Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 12 | Jan 12 – Jan 26 |
| Transplant Outdoors | February 9 | Feb 9 – Feb 23 |
| Direct Sow | January 19 | Jan 19 – Feb 9 |
| Harvest | April 6 | Apr 6 – May 11 |
| Fall Sowing | October 8 | Oct 8 – Oct 22 |
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: ideal
🗺️ USDA Zone
Zone 9b
📆 Growing Season
297 days in Solano County
Growing Tips for Napa Cabbage in Solano County
Direct sow Napa Cabbage outdoors after February 09 in Solano 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.
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 Solano County, CA?
Solano County is in Zone 9b with an average last frost of February 9. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Solano County, CA?
Solano County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 3.
Your Solano County Garden Planner — Free
A 24-page printable planner built for Solano County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.