Preventing Damping‑Off and Timing Indoor Seed Starting in Pennsylvania

When to Start Seeds in SE Pennsylvania

Last frost ≈ mid‑May. Start seeds 6 weeks prior → first week of April.

Why Seedlings Collapsed (Damping‑Off)

Sudden wilting and death after germination = damping‑off, a fungal disease favored by:

• Non‑sterile soil
• Poor air circulation (leaving humidity dome on too long)
• Overwatering

Prevention Checklist

• Use sterile seed‑starting mix (not garden soil).
• Remove plastic cover immediately at germination.
• Run a small fan for air movement.
• Water from bottom; discard excess after 2–3 hours.
• Keep soil slightly moist, never soggy.

Ideal Temperatures

• Germination: 72–75 °F.
• After sprouting: 65 °F+ is fine.
• Warmer temps needed only at flowering/fruiting (by then plants are outdoors).