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
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 ;)

wow over 300 views and no reply?

After trying everything you have said you've tried, is the cupping getting any worse?

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Originally Posted by cheeseyblue

After trying everything you have said you've tried, is the cupping getting any worse?

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on those 2 plants the problem continues with every new leaf that grows. one is very stunted and the other is quite ratty looking compared to the rest of my plants

not sure if it's getting worse but it isn't getting better and it's been like this for about 4 weeks

no more ideas? i'd really appreciate it if a more experienced grower could offer anything :)

your lucky any strain is doing alright. SOFT WATER FROM TAP is your problem if all else is good as your info.

What do you mean by soft water from tap ? If it's a water softener then it's ton of salt ! If it's municiple water then it loads of chloramine a solid frm of chorine that does not evaorate when left out. think about drinking that.

Get some distilled or reverse osmosis water and start clean. Only put what you want and your plants need back
I'm kind of hung up on ( How much poisin is too much )
If you need a good R/O filter let me know, I searched till I found a good portable that wasn't way too much for what it gives.

Quote:

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Originally Posted by LOC NAR on probation

your lucky any strain is doing alright. SOFT WATER FROM TAP is your problem if all else is good as your info.

What do you mean by soft water from tap ? If it's a water softener then it's ton of salt ! If it's municiple water then it loads of chloramine a solid frm of chorine that does not evaorate when left out. think about drinking that.

Get some distilled or reverse osmosis water and start clean. Only put what you want and your plants need back
I'm kind of hung up on ( How much poisin is too much )
If you need a good R/O filter let me know, I searched till I found a good portable that wasn't way too much for what it gives.

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it's just tap water and i live in a soft water area.

All the other plants are doing very well

Is tap water really that bad?

yes tap is that bad. Think about salts and chloramine or chlorine buiding up in you coco coir. Everything seems good with the stronger plants for a time. Now you might make it 8 or 10 weeks of flower but most likely the strong ones end up like the first weak ones. Hard to say why when everything you put in it was good. What's left ? the water.
Just start using distilled if you can't afford R/O filter. It is cheap compared to what you get in the end. Since you just flipped and a 600w you will do well. And no guessing what in it.

OHH, your smoke will taste much cleaner with no chlorine. Cause when you flush with chlorine and salts your going to taste it in the end product. You'll thank yourself.

Quote:

---

Originally Posted by LOC NAR on probation

yes tap is that bad. Think about salts and chloramine or chlorine buiding up in you coco coir. Everything seems good with the stronger plants for a time. Now you might make it 8 or 10 weeks of flower but most likely the strong ones end up like the first weak ones. Hard to say why when everything you put in it was good. What's left ? the water.
Just start using distilled if you can't afford R/O filter. It is cheap compared to what you get in the end. Since you just flipped and a 600w you will do well. And no guessing what in it.

OHH, your smoke will taste much cleaner with no chlorine. Cause when you flush with chlorine and salts your going to taste it in the end product. You'll thank yourself.

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i've never heard that before! the 2 plants that were cupping have come right since flowering so i suspect the cupping was due to vigorous growth