When to Plant Pumpkins in San Francisco, CA
Published: April 24, 2026
Pumpkin Planting Dates for San Francisco, CA
| Start seeds indoors | Year-round (avoid peak summer heat) |
| Last frost (average) | Frost-free |
| Transplant outdoors | Year-round (October–March is primary window) |
| Direct sow outdoors | Year-round (October–March is primary window) |
| Minimum soil temperature | 60°F |
| Expect first harvest | 45–120 days after planting |
| First fall frost (average) | Frost-free |
⚠ Count back 75–100 days from desired harvest date. For Halloween harvest, plant late June to mid-July. Plant 1–2 weeks after last frost.
Best Pumpkin Varieties for San Francisco, CA
Consult a San Francisco-area nursery or your state extension office for pumpkin varieties proven in Zone 10b.
Growing Pumpkins in San Francisco
San Francisco sits in Zone 10b, with an average last frost of Frost-free and first fall frost around Frost-free — giving a 365-day frost-free growing season. Warm-season crops like pumpkin need soil at 60°F or above before transplanting; San Francisco's frost calendar puts that window clearly in the late-spring to early-fall range.
San Francisco's tropical climate gives pumpkin year-round potential, but dry season (roughly October through April) is the primary productive window. Wet season rains drive fungal disease fast enough to destroy an unprotected crop within a few weeks. Plan main plantings for dry season and keep beds well-drained.
San Francisco's mixed soil conditions vary block by block — get a soil test if you have not in three years. Generally, a base of quality compost (2 to 3 inches annually) and consistent watering at 2 inches per week serves pumpkin well across most soil types found in San Francisco.
Pumpkin Calendar for San Francisco
| Month | Task |
|---|---|
| Year | Start seeds indoors under grow lights |
| Frost | Last frost — harden off seedlings outdoors |
| Year | Transplant outdoors into warm soil |
| Frost | First fall frost — harvest remaining, end of outdoor season |
Pumpkin Tips for San Francisco Gardeners
- •For Halloween pumpkins, count back 75–100 days from October 31 — plant between late June and mid-July in most climates.
- •Plant on hills or mounds to warm soil and improve drainage; two plants per hill is plenty.
- •In San Francisco's tropical climate, focus on dry-season plantings (October–April) and use raised beds with excellent drainage for wet-season success.
Common Pumpkin Pests in San Francisco
- •Squash Vine Borer — peaks June–August in Zone 10b (active March–October); sudden wilting with frass at stem base; inject Bt into the stem or use row covers through flowering.
- •Squash Bug — peaks June–August in Zone 10b (active March–October); gray-brown shield bugs that suck plant sap; handpick and destroy egg clusters on leaf undersides.
- •Cucumber Beetle — peaks June–August in Zone 10b (active March–October); yellow and black striped beetles that spread bacterial wilt; trap with yellow sticky traps.
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Pumpkins in San Francisco
In San Francisco's tropical climate, Corn and Bush Bean are the most beneficial plants to grow alongside pumpkin. Corn provides vertical support for climbing companions in the Three Sisters planting. Keep pumpkin away from Potato — it competes for nutrients and shares blight diseases. In humid tropical climates, spacing companions with airflow in mind prevents fungal disease from spreading through dense plantings.
Frequently Asked Questions
When should I plant pumpkin in San Francisco, CA?
In San Francisco (Zone 10b), start pumpkin seeds indoors around Year-round (avoid peak summer heat) and transplant outdoors around Year-round (October–March is primary window). The city's average last frost of Frost-free is the anchor date — count 3 weeks back for seed starting and 1 weeks forward for transplanting.
What zone is San Francisco, CA for pumpkin growing?
San Francisco is USDA Zone 10b. For pumpkin, this means a frost-free growing season of roughly 52 weeks running from Frost-free to Frost-free. This is a comfortable window for warm-season crops like pumpkin — standard varieties work well.
When is pumpkin harvest season in San Francisco?
Expect the first pumpkin harvest in San Francisco around 45–120 days after planting. This is based on 75–100 days from transplant or direct sow.
How long does it take to grow pumpkin in San Francisco, CA?
From transplant or direct sow to first harvest, pumpkin takes 75–100 days in San Francisco's climate. Based on a typical planting date of Year-round (October–March is primary window), expect your first harvest around 45–120 days after planting. San Francisco's warm Zone 10b climate tends toward the faster end of this range — warmer soil and longer days accelerate maturity.
What soil does pumpkin need in San Francisco?
San Francisco's soil conditions vary block by block. Before planting pumpkin, do a soil test (most state extension offices run them for $15–30). The test reveals pH, key nutrient levels, and organic matter content, so you can amend appropriately rather than guessing. Generally, 2–3 inches of compost annually improves most soils for vegetable production.