Yellow, curling leaves with black tips

[SteelieMark]

My plants are getting covered with yellow, curling leaves with black tips, which continues until the leaf completely withers.
Been feeding fox farm nutes as recommended, plus fish emulsion every couple of weeks
I've tried to troubleshoot this but there seems to be more causes than treatments
Has anyone else experienced this?
I'm in New England, outdoor grow

 

[GNick55]

My plants are getting covered with yellow, curling leaves with black tips, which continues until the leaf completely withers.
Been feeding fox farm nutes as recommended, plus fish emulsion every couple of weeks
I've tried to troubleshoot this but there seems to be more causes than treatments
Has anyone else experienced this?
I'm in New England, outdoor growView attachment 2033738

well could be a few things..
are you able to post pictures of the plant, a couple different angles, some close, from above..

 

[bguwop420]

Nute burn and possibly underwatering

 

[SteelieMark]

I'm beginning to think this is nutrient burn; the potting mix was some off brand and was mixed with bag compost manure. Definitely not under/over watered as they were checked daily ; they have gravel in the base of pots and drain properly.
Strains are Tropicana Cookie, Apollo20 and I think 1 Durban Thai, lost the tag