flowering, afew lower leaves yellowing

[faintfuzzies]

first off i just lost all but 1 medical legal plant due to a climate disaster, my vent to outside stayed open from a branch keeping vent door open it let all this cold 10 degree f air into room threw light and i went in room other day and it was about 10 degree F so i lost all but 1 plant.I have 1 plant left plant that was in the small room flowering it was saved becuase it was not near that disaster room, but this one plant is in 5th week of flower and doing really well but i did take some large yellow fan leaves off today maybe 3-4 large lower leaves The plant is a big plant 3+ft tall. in the 5th week of flowering( nice big flowers and they look real good is this normal or should i up the nitrogen a little bit. im using advanced nutes micro grow and bloom Im in sunshine mix #4 advanced mix my ppm is at 1150 and ph is between 6.0-6.2 ..most of time about 6.1ph.. I think its normal to see some yellowing in flowering but this is my first round and im not 100% sure. I want to make sure its happy being i lost all my other plants do to the cold . what a nightmare , my heart dropped.

Faint

 

[grow_right]

as the palnt uses up the available nitrogen, the oldest leaves will yellow and be pushed off. as long as the younger upper leaves are fine, then all's well. if you do not supply nitrogen, you may want to add some. even though the plant is in flowering, they still require it for normal growth.