Seedling problems :-(

[Kingkrab]

Hi y’all! Got this little seedling going and it was going fine for the first week. Now it looks like it stopped growing and it’s got some brown stuff on the leaves.

growing in coco
only ph 5.5 water with a tiny amount of Canna Start so far.

[Tersky]

Did you buy pre washed and pre buffered coco or wash and buffer it before planting? I dont know about those nutes but does it have cal mag in it? If not you need cal mag for coco. Aslo your ph is too low. Ph to 6.0 to be able to absorb the full spectrum of nutes. Last it looks like there is no perlite in the medium. Ideally you want 30% to 50 perlite to allow for proper drainage and airflow or else the seedlings can drown with improper watering practices.

[crucialbunny]

I don't know much about growing in coco but it looks dense and could be suffocating the roots. Is there anything in there for drainage?