When to Plant Cosmos in Irvine, California (92616)

Location

Irvine, California

ZIP Code

92616

USDA Zone

10b

Last Frost

Thursday, January 15, 2026

📅 Planting Calendar

Direct Sow Outdoors Thursday, January 15, 2026

Pro Tip: Sow Cosmos directly outdoors around your last frost date when soil starts to warm.

🌿 Plant Details

Scientific Name Cosmos bipinnatus

Days to Maturity 60 days

Mature Height 24-60"

Spread 18"

Type Annual

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Low-Moderate

↔️

Spacing

18" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 7-14 days

Ready to Plant Cosmos in Irvine?

Get your seeds now so they're ready by Thursday, January 15, 2026.

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Growing Cosmos in Zone 10b

Cosmos (Cosmos bipinnatus) is a popular garden vegetable. In Irvine, California, which is in USDA Hardiness Zone 10b, you should direct sow seeds around Thursday, January 15, 2026.

Your average last frost date is Thursday, January 15, 2026. Cosmos grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.