Stop growth

hello iam kinda new at this i have a purple strain marijuana plant in a little box i made and i want to now how or what do i need to do to stunnt the growth of the plant and so it make a get wide like get more steams coming out of the main stock or steam.. i have the plant in soil with a 300w or 400w light dont remmeber and i dont have much space so want to get the most yield i can

help

Google LST :rastasmoke:

hey there...lots of ways to increase yield...topping...LST(low stress training)....increase veg time...here's a before and after shot, of a plant,that has been topped and LST'ed....photo's are 5 days apart.....