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When to Plant Spaghetti Squash in San Diego County, CA

Spaghetti squash is a winter squash whose cooked flesh separates into pasta-like strands. It is a popular low-carb alternative to pasta.

San Diego County, California is in USDA Zone 10b. The average last spring frost is April 16 and the first fall frost is November 1, giving you a growing season of approximately 199 days.

At an elevation of 2,613 feet, San Diego County receives approximately 18.2 inches of rainfall annually with predominantly loam soil. Summer highs average 92ยฐF, providing good warmth for Spaghetti Squash during the growing season. With low rainfall, drip irrigation is essential for growing Spaghetti Squash successfully. Mulch heavily to conserve soil moisture.

San Diego County, CA (Zone 10b) Moderate season
199 days
Last Spring Frost April 16
199 growing days
First Fall Frost November 1

San Diego County Soil Profile

Soil Type

Loam

Soil pH

5.7-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (68 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 16 – Aug 13
Recommended (50%) ✓ Fits season (73 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jul 23 – Aug 20
Safe Start (90%) ✓ Fits season (69 days to spare)
Start indoors: Apr 23 Transplant: May 28 🍅 Harvest: Aug 27 – Sep 24

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
1.0″/week
Rainfall provides
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,309 gal / 100 sq ft
Drought risk

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

Spaghetti Squash needs ~1,758 GDD — county provides 3,781 GDD Excellent fit

Spaghetti Squash Planting Timeline โ€” San Diego County, CA

Spaghetti Squash Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 โ€“ Apr 2
Transplant Outdoors April 23 Apr 23 โ€“ May 7
Direct Sow April 16 Apr 16 โ€“ May 7
Harvest July 23 Jul 23 โ€“ Aug 20

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 10b

Growing Season

199 days

Growing Tips for San Diego County

Direct sow on mounds after last frost. Harvest when skin turns golden yellow and is hard. Store in a cool, dry place for 2-3 months. Bake or microwave halves until tender.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

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Frequently Asked Questions

When should I plant Spaghetti Squash in San Diego County, CA?

San Diego County is in Zone 10b with an average last frost of April 16. Plan your Spaghetti Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is San Diego County, CA?

San Diego County, California is in USDA Hardiness Zone 10b. The average last spring frost is April 16 and first fall frost is November 1.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help San Diego County gardeners in Zone 10b organize planting dates, track what's growing, and never miss a planting window.

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