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When to Plant Zinnia in Broomfield, Colorado (80021)

Location

Broomfield, Colorado

ZIP Code

80021

USDA Zone

6a

Last Frost

Monday, April 20, 2026

📅 Planting Calendar

Direct Sow Outdoors Monday, April 27, 2026

Pro Tip: Sow Zinnia directly outdoors 1 week after your last frost date — it needs warm soil.

🌿 Plant Details

Scientific Name Zinnia elegans
Days to Maturity 60 days
Mature Height 12-36"
Spread 12"
Type Annual

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Moderate (1 inch/week)

↔️

Spacing

12" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 5-10 days

Ready to Plant Zinnia in Broomfield?

Get your seeds now so they're ready by Monday, April 27, 2026.

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Growing Zinnia in Zone 6a

Zinnia (Zinnia elegans) is a popular garden vegetable. In Broomfield, Colorado, which is in USDA Hardiness Zone 6a, you should direct sow seeds around Monday, April 27, 2026.

Your average last frost date is Monday, April 20, 2026. Zinnia grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.