Can be many things.
If your medium is coco they can be underwatered. U need to water everyday.
If ur medium is soil they can be over watered as well.
Can be wrong ph! If that is the issue, measure the runoff and see if the ph is the same that u pour in to the plant. Or in the accepted values. If not! Make a flush. YouTube it.
Can be to hot in ur tent or dry.. try 50rh and like 24 Celsius and u will be fine
Try all these things if it doesnât work make a new question then tag my name.
The phenotype is not sour diesel, the strain is sour diesel.
Phenotype is a whole different thing, every strain has different phenotypes. Each pheno has their own characteristics âşď¸ good luck my friend!