what r they need more or less? please help me out

hi all

here my first week of flowering. few plants look bit sick. leaves are yellowish , some of them have some yellow spots. in total 3 plants doesn't look ok, all the rest 17 lookks good IMO. So guys, anyone can halp me, what these girls needs more or less, here is the pics. all in cocó's, cana coco nutes + I gave them canna booster on the last watering, but them leaves was yellow before the booster. also, when they were younger I was giving them extra nitrogen, to promote the growth.

Other thing is, do u think that all my garden is bit too much compressed? or should i try spread them bit wider as i do have some spare space in the tent. but then means, that I will have to rise the lights to cover all of them and I am i right by thinking that then plants will strech up more. coz I start to worrie, taht by the end of flowering I will not have anymore space in hight.

Sorry for the mess I putted all in here, but hope u understand my point, or just replay if u don't, I will tray to explain more aqurate. Thank u in advance for ur support.

here is the few pics.

Check PH what are you feeding them?

View attachment 2413197always helps me

Looks like lack of potassium. In the stage they're in they need potassium and phosphorous. The PK of the NPK.

cheers for replay

the ph is ok, see the nutes bufering the ballans of ph, but I did looked at it and it was 6.5 or so. I do have a botle of PK 13/14. Do u think I should give them , wouldn't it make any harm for them?

you should do a run off test that is classic ph problem you can tell by the distorted leaf tips / how did you test your soil ph