When to Plant Petunias
Cheerful, trumpet-shaped flowers that bloom nonstop from spring through frost. Perfect for containers, hanging baskets, and borders.
The Short Answer
How to Grow Petunias
Petunias are divided into grandiflora (large flowers, fewer blooms, rain damage) and multiflora (smaller flowers, more blooms, weather resistant) types. Wave and Supertunia types are spreading forms that fill containers and cover ground without pinching or deadheading. Traditional types benefit from pinching leggy stems in midsummer — cut them back by half, apply fertilizer, and they'll flush back within 2 weeks. Feed every 2 weeks with liquid fertilizer for continuous bloom. Petunias are heavy feeders that exhaust container soil quickly.
Starting Seeds Indoors
Begin petunias seeds indoors 10 weeks before your average last frost date. Seeds need soil temperatures of at least 60°F to germinate, which typically takes 7-14 days. Provide 14 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 7 days before transplanting by gradually exposing them to outdoor conditions.
Growing Tips
Pinch leggy stems to encourage branching. Feed every 2 weeks for continuous bloom. Wave and Supertunia types are self-cleaning — no deadheading needed.
Companion Planting
Good companions:
Petunias Planting Dates by State
Click your state for petunias planting dates specific to your location:
Last reviewed: March 29, 2026