Leaf burn / brown spots? help!

[leaflet]

Hey guys,

long time lurker, now i made an account because i need some help...
It's been a few years, now i started a new grow with some new conditions, and i'm worried about my babies. In the last few days, some leafs started to rapidly yellow/brown, and i can't tell what the problem is.
Some infos on the environment: grow medium coco; mineral fertilizer Terra Aquatica TriPart; PH around 6; EC around 1,5 mS; temperature around 25 degrees celsius, and enough light
I took some pictures too - the first and second are of the most dire looking plant, number 3 is from another where the problem seems to start.

What do they need? Thanks for having a look!

 

[fmor1965rob]

Had plants that looked like that i was trying to grow in a 1gallon no matter what I did to bring them back it got worse as soon as I put them In 5 gallon pot and they came back to life not to say their root bound but those pots look awfully small

 

[leaflet]

Hmm interesting! I had plants in even smaller pots before to maximise space, but i'll try to get some bigger ones soon, thanks.
A friend also brought up that it might be phosphorus deficiency? I did see some leafs growing weird/furled, so i guess that checks out?

 

[fmor1965rob]

Hmm interesting! I had plants in even smaller pots before to maximise space, but i'll try to get some bigger ones soon, thanks.
A friend also brought up that it might be phosphorus deficiency? I did see some leafs growing weird/furled, so i guess that checks out?

It can be but lots not time I do more damage trying to fix it ,most time I have plant that look sick ill put in bigger pot with fresh grow media seems to work for me instead of giving it a flush or a nutrient on what I think it needs try what you think, it be it could be that ? I always had better result repotting

 

[MariJan]

Hey guys,

long time lurker, now i made an account because i need some help...
It's been a few years, now i started a new grow with some new conditions, and i'm worried about my babies. In the last few days, some leafs started to rapidly yellow/brown, and i can't tell what the problem is.
Some infos on the environment: grow medium coco; mineral fertilizer Terra Aquatica TriPart; PH around 6; EC around 1,5 mS; temperature around 25 degrees celsius, and enough light
I took some pictures too - the first and second are of the most dire looking plant, number 3 is from another where the problem seems to start.

What do they need? Thanks for having a look!

Yes if you can up pot it fo do, but the brown spots and lower yellow leaves are nutrient deficiencies . Put some cal mag on her or cal nit with epsom. Not both one or the other

 

[WeedHopper]

CalMag for sure.

 

[Flower]

Needs more CalMag.

 

[Carty]

I can hear my buddy Bigsur telling me years ago.... MORE CALMAG. I now use it from week 2 up to week 7
on my Auto plants.... I've not had any necrosis since.

To make sure this is your issue.. give your plant a nice flush, maybe run a gallon of water thru her, then feed
her 1 tsp Calmag and watch the newer growth.... remove the large leaf with necrosis on it really bad so the plants not trying to fix it....

Basic foods at half strength for now... see where this takes ya

 

[leaflet]

Thanks for the tips folks! I did get some calcium magnesium now, and adjusted PH down a bit (got that recommended for coco)
Will update how it goes