Blog

When to Plant Cucumber in Humboldt County, CA

Cucumbers are a warm-season vine crop available in slicing and pickling varieties. They are prolific producers when given warmth, moisture, and a trellis to climb.

Humboldt County, California is in USDA Zone 9a. The average last spring frost is February 27 and the first fall frost is November 28, giving you a growing season of approximately 274 days.

At an elevation of 148 feet, Humboldt County receives approximately 22.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 87ยฐF, providing good warmth for Cucumber during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Cucumber will need more frequent watering and organic matter to retain nutrients.

Humboldt County, CA (Zone 9a) Year-round
274 days
Last Spring Frost February 27
274 growing days
First Fall Frost November 28

Humboldt County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (164 days to spare)
Start indoors: Jan 16 Transplant: Feb 20 🍅 Harvest: Apr 17 – Jun 12
Recommended (50%) ✓ Fits season (155 days to spare)
Start indoors: Jan 30 Transplant: Mar 6 🍅 Harvest: May 1 – Jun 26
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 4 – Jul 30

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
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 2,845 gal / 100 sq ft
Cucumber needs ~915 GDD — county provides 4,193 GDD Excellent fit

Cucumber Planting Timeline โ€” Humboldt County, CA

Cucumber Planting Calendar

Activity When Date Range
Start Indoors January 30 Jan 30 โ€“ Feb 13
Transplant Outdoors March 6 Mar 6 โ€“ Mar 20
Direct Sow February 27 Feb 27 โ€“ Mar 20
Harvest May 1 May 1 โ€“ Jun 26

Plant 0.5" deep ยท 24" apart ยท Rows 48" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

50โ€“70 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 9a

Growing Season

274 days

Growing Tips for Humboldt County

Direct sow after last frost or start indoors 3 weeks early. Provide a trellis for vining types to save space and improve air circulation. Harvest frequently to encourage production.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Sage

Level Up Your Garden

Frequently Asked Questions

When should I plant Cucumber in Humboldt County, CA?

Humboldt County is in Zone 9a with an average last frost of February 27. Plan your Cucumber planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Humboldt County, CA?

Humboldt County, California is in USDA Hardiness Zone 9a. The average last spring frost is February 27 and first fall frost is November 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Humboldt 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 Humboldt County, CA. Local conditions may vary. Last updated: April 2026.