A little help please??

ok so my plant is 4 weeks old..shouldnt it be a little bigger?Im useing 100w light on 18/6

Yeah, it should be bigger - whats your temps? Are you PH'ing your water? To what?
Lets start there.
GWN

My temp reaches 79degrees highest, and its off cycle it reaches 70 degrees. No i do not PH my water i use purified water. and merical grow nutes ( iknow its not the best but seems to work)

Wut kinda light is that?