Plants need light every day. Leave them under lights until time to transplant. Ease them in to full sun. No more than 2 hours the first day. Fan should be running after seeds sprout IMO.

taz,

I never worry about a fan until after the seedlings have been potted up and grown a bit. Of cou-rse, YMMV!

Mike

Since I sprout all my seeds in the pots they will stay in until transplanting in the garden on my gas stove(pilots for bottom heat)and the lighting is not that good, all seedlings get moved to one of 3 shelves along with other plants of all sizes and shapes where the fan runs constantly. Due to lack of space(in my case) they get air as soon as sprouted. They seem to do great and I never have problems with damping off. WFM!

Exactly what taz said in his first post. Leave the fan on 24/7. It constantly renews fresh air around the plants and it also makes the plants sturdier and stronger for a healthy, happy, outdoor life.