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When to Plant Celery in Solano County, CA

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.

Solano County, California is in USDA Zone 9a. 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 95ยฐF, so Celery may need afternoon shade and extra watering during peak heat.

Solano County, CA (Zone 9a) Year-round
297 days
Last Spring Frost February 9
297 growing days
First Fall Frost December 3

Solano County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (165 days to spare)
Start indoors: Dec 28 Transplant: Jan 25 🍅 Harvest: Apr 19 – Jun 14
Recommended (50%) ✓ Fits season (157 days to spare)
Start indoors: Jan 12 Transplant: Feb 9 🍅 Harvest: May 4 – Jun 29
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Feb 13 Transplant: Mar 13 🍅 Harvest: Jun 5 – Jul 31

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.7″/week
Watering frequency 2-3 times/week
Season total 4,394 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Celery needs ~2,125 GDD — county provides 6,332 GDD Excellent fit

Celery Planting Timeline โ€” Solano County, CA

Celery Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 โ€“ Jan 26
Transplant Outdoors February 9 Feb 9 โ€“ Feb 23
Direct Sow January 19 Jan 19 โ€“ Feb 9
Fall Sowing October 8 Oct 8 โ€“ Oct 22
Harvest May 4 May 4 โ€“ Jun 29

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Direct Sow
February Transplant Outdoors Direct Sow
March โ€”
April โ€”
May Harvest
June Harvest
July โ€”
August โ€”
September โ€”
October Fall Sowing
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

80โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 9a

Growing Season

297 days

Growing Tips for Solano County

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

  • Carrots
  • Parsnip

Level Up Your Garden

Frequently Asked Questions

When should I plant Celery in Solano County, CA?

Solano County is in Zone 9a with an average last frost of February 9. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Solano County, CA?

Solano County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Solano County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Solano County, CA. Local conditions may vary. Last updated: April 2026.