Posted: 19/04/2013 at 08:22
Jak, it's the light that goes straight through the bubble wrap. The light is the crucial thing. Clear bubble wrap, obviously. Before I put them outside I had them under a couple of bright desk lamps inside, the globes about 2" above the seedlings.
How big are the leggy seedlings? If they're not ready to plant out yet you can try resetting them down deeper and giving them as much light as possible.