As far as the rootbound issue, it isn't a terrible thing for a plant to finish rootbound. You should make sure that it has a total of 1 gallon of soil for every 12 inches of height that you expect it to finish at. Then it will all come out about right.
Bear is right about the N... the plant needs just the bare minimum of N to keep green until week 5 or so of flower for an 8 week cycle, or even later for a long-flowering sativa.
I avoid both problems by repotting into a 3 gallon container after week 2 of flower and mixing some organic N (Neptunes Harvest kelp and seaweed fertilizer has been on the menu lately) right into the soil for the repot... then as the roots grow into it they will get just a bit of N to finish. I apply it at a rate of about 4 tablespoons undiluted fert in the 3 gallon pail of dirt, mixed REALLY REALLY well.
stinkyattic Reviewed by stinkyattic on . root bound during flowering question how do u know if Ur plant is root bound during the flowering cycle.Ive read if your fan leaves continues to yellow until all the fan leaves are gone and also u can get n deficiency from being root bound.now does that goes with the plant being in budding or is it during veg,plus can i add more dirt in the container during flowering would it effect the plant in anyway ..........reason im asking,well my fan leaves are yellowing bad and dying off,plus half of my soil in the container seems to be Rating: 5