also range the ph from 5.7 to 6.3 when watering so plant gets all the nutes it needs not more of 1 and not enough of the other and air flow is important.
hi mate so you have limited height what i would do if i was you would be to put a cage of chicken wire over top of plant after topping as plant groes upwards in to the wire you spread side branches outwars this is called screen of green system or scrog it will keep alot of fowledge down...