When to start using light?

[Paht_Hed]

When should I start using my grow light on seedling? as soon as they sprout or should I give them some time to settle before applying light?

[KHAN]

depends what light you have?

[Paht_Hed]

Oh sry (newbie here). Right now I am using a 100 watt daylight flourescent bulb in my regular bulb socket in the walk-in closet that I use as my grow room. It is about 8 feet from the 3 seedlings I have right now... They are about 1 - 1.5 inches long.
I hope to switch to a 25 watt LED grow light (picture below) as soon as I can get it in. Also, should I perchaps purchase a mobile socket so I can place the light closer to the sprouts?