When to plant Celery in Napa County, CA
Napa County gardeners should plant Celery between February 5 and February 26 in spring. With Napa County's Zone 9b climate (last frost February 26), Celery needs 80–120 days to mature — plant by July 29 for a full harvest. A second sowing from October 1 to October 15 extends the harvest into fall.
When to Plant Celery in Napa County, CA
Napa County, California gardeners: here's your July plan
Each item below is timed to Napa County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Bring in the celery
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.
Napa County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.
At an elevation of 449 feet, Napa County receives approximately 35 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Celery during the growing season.
Napa County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.5
Drainage
Well Drained
Celery 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 Napa County
How your county's soil matches Celery's growing requirements.
Soil pH
Your soil pH (6.7–7.5) is more alkaline than Celery prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Napa County is excellent for Celery — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Celery is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Celery.
How to Plant Celery
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Celery
Sow every 9.1 weeks. Last sowing by Jul 29 to harvest before frost.
For a dedicated fall crop, sow by Oct 01.
Celery Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Celery
Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.
| Month | Celery Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 7.5" | 0" | ❄️ Dormant |
| Feb | 5.6" | 7.8" | 0" | ✅ Rainfall sufficient |
| Mar | 5.6" | 5.8" | 0" | ✅ Rainfall sufficient |
| Apr | 5.6" | 2.3" | 3.3" | 🚿 Regular watering |
| May | 5.6" | 0.8" | 4.8" | 🚿 Regular watering |
| Jun | 5.6" | 0.2" | 5.4" | 🚿 Regular watering |
| Jul | 5.6" | 0" | 5.6" | 🚿 Regular watering |
| Aug | 5.6" | 0" | 5.6" | 🚿 Regular watering |
| Sep | 5.6" | 0.3" | 5.3" | 🚿 Regular watering |
| Oct | 5.6" | 1.3" | 4.3" | 🚿 Regular watering |
| Nov | 5.6" | 3.3" | 2.3" | 💧 Light watering |
| Dec | — | 5.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Napa County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Celery 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.
Celery Planting Timeline — Napa County, CA
Celery Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 29 | Jan 29 – Feb 12 |
| Transplant Outdoors | February 26 | Feb 26 – Mar 12 |
| Direct Sow | February 5 | Feb 5 – Feb 26 |
| Harvest | May 21 | May 21 – Jul 16 |
| Fall Sowing | October 1 | Oct 1 – Oct 15 |
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 | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.3"/week · 2-3 times/week
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
273 days in Napa County
Growing Tips for Celery in Napa County
Direct sow Celery outdoors after February 26 in Napa County when soil has warmed and frost danger has passed.
Common pests for Celery in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Celery in Other Locations
Frequently Asked Questions
When should I plant Celery in Napa County, CA?
Napa County is in Zone 9b with an average last frost of February 26. Plan your Celery planting based on this frost date — see the calendar above for exact timing.
What planting zone is Napa County, CA?
Napa County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 26.
When should I plant Celery in Napa County, CA?
In Napa County, CA, plant Celery after the last frost (around February 26) and before the first frost (around November 26). Best results when soil holds above 50°F.
What growing zone is Napa County, CA for Celery?
Napa County sits in USDA Zone 9b. Celery grows reliably in zones 2a through 10b, so it's a good fit here.
Can Celery grow in Napa County's climate?
Yes — Celery grows well in Napa County's temperate climate. Napa County averages a 274-day frost-free season, with last frost around February 26 and first frost around November 26.
Your Napa County Garden Planner — Free
A 22-page printable planner built for Napa 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.