BudXsanswered grow question 5 years ago Environment baby!!!! 4 weeks into veg and something is off. If you dont have enough fresh air in - slow growth. Too little light - slow growth. Too high temps/humidity - slow growth. All leads to smaller yields and never reaching the plants potential.
I would look at a quick online tutorial on room set up, check to see how your room stacks up, and adjust where you can. Everyone makes improvements, every grow. Its the beauty of the hobby. Get to reading:)