When to Plant Onion in Whittier, California (90607)

Location

Whittier, California

ZIP Code

90607

USDA Zone

10b

Last Frost

Thursday, January 15, 2026

📅 Planting Calendar

Start Seeds Indoors Thursday, November 20, 2025

Transplant Outdoors Thursday, January 29, 2026

Pro Tip: Start Onion seeds indoors 8 weeks before your last frost date, then transplant outdoors around Thursday, January 29, 2026.

🌿 Plant Details

Scientific Name Allium cepa

Days to Maturity 100 days

Mature Height 12-18"

Spread 4"

Type Bulb

Fruit Size Medium (2-4 inch bulb)

☀️ Growing Requirements

☀️

Sun

Full Sun (6+ hours)

💧

Water

Moderate

↔️

Spacing

4" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 7-10 days

Ready to Plant Onion in Whittier?

Get your seeds now so they're ready by Thursday, November 20, 2025.

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🤝 Good Companions

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⚠️ Avoid Planting Near

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Growing Onion in Zone 10b

Onion (Allium cepa) is a popular garden vegetable. In Whittier, California, which is in USDA Hardiness Zone 10b, you should start seeds indoors around Thursday, November 20, 2025.

Your average last frost date is Thursday, January 15, 2026. Plan to transplant your Onion seedlings outdoors around Thursday, January 29, 2026, about 2 weeks after your last frost date.