When to Plant Zinnias
The cut-and-come-again champion. The more you cut zinnias, the more they bloom. A cottage garden essential.
The Short Answer
How to Grow Zinnias
Zinnias are the easiest cut flower from seed and the backbone of any cut flower garden. The more you cut, the more they produce — a single plant can yield 50+ stems over a season. For longest vase life (7-10 days), cut when the petals feel firm, not soft. Giant varieties (Benary's Giant, Oklahoma) produce stems long enough for tall arrangements. Profusion and Zahara series are mildew-resistant and better for humid climates. Direct sow after frost — zinnias resent transplanting. Deadhead spent flowers to keep production going.
Starting Seeds Indoors
Begin zinnias seeds indoors 4 weeks before your average last frost date. Seeds need soil temperatures of at least 60°F to germinate, which typically takes 5-7 days. Provide 12 hours of light per day using a south-facing window or grow lights.
Transplanting
Move seedlings outside 1 weeks after your last frost date, once soil temperatures reach 60°F. Harden off seedlings for 5 days before transplanting by gradually exposing them to outdoor conditions.
Direct Sowing
Zinnias can be direct sown 1 weeks after your last frost date. Plant seeds 0.25" deep, spaced 9" apart.
Growing Tips
Water at the base to prevent powdery mildew. Cut flowers just above a leaf node to encourage more branching and blooms.
Companion Planting
Good companions:
Zinnias Planting Dates by State
Click your state for zinnias planting dates specific to your location:
Last reviewed: March 29, 2026