Stunted autoflower plant

In coco coir you have to water them everyday single day!!! You need to water until you get 20-30% runoff to prevent salt build up in your medium! So I really recommend to feed her more frequently. If she is getting a little droopy then you can wait 1 day until next feed. But that the thing with coco, feed everyday. You have a nitrogen deficiency as well that’s why she’s turning yellow! You may also have a ph problem. So feed her until the ph of the runoff is the same as you pour in. Good luck my friend 🙏🏼🤩

Holy coco puffs batman.

Looks like bad watering practices and a medium that needs some more aeration. With coir you want to mix in about 30% perlite and water the entire pot. The roots will die back if they hit a dry pocket. and then the over all root mass will have a direct relation to the overall size of the plant. The fabric pots allow for air pruning when they reach the edge. but air pruning of the roots before they hit the edge is no ideal. I'd also wonder if the concentration of the feed is high enough. Try watering the whole pot and getting some runoff to prevent salt buildup. allow a dry back cycle before watering again and next grow mix in some perlite. 30%

Air pocket/barrier dont help to grow healthy plant, roll that pot wall down ! By look, lack of magnesium, epsom salt easiest way to add it. Dying cotyledons are sign of imbalance, do you measure ph ? How often you water, coco is barely saturated in picture ... do you water enough ???