Cold Frame Seed Starting: Timing and Ventilation

Move seedlings to cold frame at 4 true leaves. Tomatoes benefit from potting up deeper each time (builds root nodules). Use automatic vent openers (e.g., Master Gardening) to prevent overheating when you're away.

Setup Essentials

• Auto-vent: opens at ~45°F, closes when cool.
• Don't transplant to larger pots unless roots are crowded—except tomatoes.
• Harden off 1 week before garden planting.

Automation = peace of mind.