novice here - i've read a fair bit and am stuck on this problem - hope you can help

I'm growing indoor, hydro, in coco
slab runoff ph is 5.5 - 6, water is soft water from tap
i'm using CX ferts (headmasta, wilt guard, regen-a-root)
the plant is 7 weeks old

i've been using fluro lighting which was maybe 7 inches from top of plants, until 11 days ago when i switched to 600w HPS for flowering and raised it 20inches from top of tallest plant

day temp = 18-21 degrees Celsius
dark temp = 12-16 degrees Celsius
humidity is fluctuating but around 50%

switched lights to 12/12 11 days ago from 18/6

ventilation is good as tent is in an outdoor shed with plenty of airflow, fan blowing directly onto HPS to reduce heat and flaps open on tent for circulation

so - 8 plants, mix of sativa, indica and hybrids

most are very happy and strong but 2 sativa are stunted with their leaves cupping up in an extreme way, both from "Big Buddha The Kali" seed

i've tried reducing watering & ferts, flushing medium for 2 days, reducing heat & humidity, moving lights further away, but 2 plants leaves are cupped like this (see pic)

Attachment 286815

you can see the leaves of the plants around are healthy, just two that are like this

really short of ideas myself - anyone offer any experience? HELP! basically
dannydevon Reviewed by dannydevon on . leaf cupping novice here - i've read a fair bit and am stuck on this problem - hope you can help :) I'm growing indoor, hydro, in coco slab runoff ph is 5.5 - 6, water is soft water from tap i'm using CX ferts (headmasta, wilt guard, regen-a-root) the plant is 7 weeks old i've been using fluro lighting which was maybe 7 inches from top of plants, until 11 days ago when i switched to 600w HPS for flowering and raised it 20inches from top of tallest plant day temp = 18-21 degrees Celsius Rating: 5