Coupme Questions Some Help Please

[mr x]

my plant is 3 weeks old and is on its 3rd set of leaves how tall do you let it grow before topping it i dont want a super tall plant and 2 question is at 3 weeks how big should my plant be how many leafs should it have?

 

[str8smokn]

What kind of light is that.?
You will need to drop it down to keep plant from stretching.
I usually top at the 5th node . If you want a 2’ tall plant then you need to flip the lights at 1’ tall plant.
STR8

 

[Buzzer777]

Could you supply more info?..ie: medium (soil?), watering etc..And what happened to that lower leaf?
If you cut it off..the plant is too sparse to do that imo..
Something (besides stretch) is just not right and I can't put my finger on it..

 

[Hydro head]

What light you using? Looks very stretched, also change the tin foil for white mylar or even white paint as tin foil will cause hotspots and can burn your plant