when to start nutrients?

my girls are about 4 weeks and a few days old. the pics were taken at about 3 1/2 weeks old.

theyre showing some brown/faded/yellow spots.

the soil im using is called expert gardener potting soil and has an npk of 7-1-3. it seems quality and drains very well. the nutrients included are "coated slow release" meaning you never have to feed your flowers or w/e.

i was afraid id fry em because of the slow release but the leaving are showing signs of something.

my temps in my box are around 75-80 and will go down as the season changes.

they get water whenever the soil has dried, usually every two days (32oz pots). sometimes everyday. always in the morning.

so should i add nutes? what would you guys reccomend for me at this stage?

Are you misting the plants and allowing back to light before dry between overlapping leaves? My other guess would be thrip laying eggs in the leaf overlap. Any slippery silvery trails or speckles?
I'd be careful adding more nutes to a slow release makeup. Plants don't appear to be lacking nutes or even overferted. Too early to panic, i'd wait a bit and see if it progresses.

how are you going to transplant those if they are tied down like that to dixie cups? i would give them a 1/4 strength when they start to turn lighter green. right now they are super dark green which means they have plenty of nutrients. but they are looking good.

LOL they dont make 32oz dixie cups. no transplanting unless 100% rootlocked. im trying to keep them small as possible considering i have a little less then 3 feet vertically.l

one of them is definatly an indica and i dont plan on seeing the leaves get too much brighter on that one.

thrip? my cabinet is inside of a closet, i couldnt imgaine bugs could get to it if they wanted.

im at 4 weeks and 5 days, i think im going to switch to 12/12 today as i dont want them getting too big. the indica is showing alternating nodes on the two main branches and the other one is gettin pretty large, 7"+

if during flowering there is a problem with the small pots i will transplant, not too hard. just untie them first! haha. most of the branches kinda stay that way now anyway.

thanks so much guys rollitup has been such a tremendous help on my first grow