Fixing Leggy Tomato Seedlings: The Light Solution

Cause: Insufficient Light

Weak, thin stems on indoor seedlings are almost always due to inadequate light. A windowsill in late winter/early spring rarely provides enough intensity.

Fix: Grow Lights

• Use fluorescent or LED shop lights (tabletop or tiered system).
• Keep lights 2–3 inches above plant tops at all times.
• Run 12–14 hours daily (timer recommended).

Result

Stocky, sturdy stems with short internodes — plants that transplant well and produce heavily.