Imo u need to be laser focused on the basics. The leaves are drooping and discoloring. This is a classic sign especially for newbies (i did it too). Every possibility you think of could be valid i.e. fertilizer light etc but in truth it all stems from one thing.
How, when and in what are you watering.
1. Do not use containers without drainage.
2. Water when the plants need it.
3. Do not overwater. Do not water too frequently.
Getting the basics right-- good soil, light, airflow, temp, humidity are more important than they seem. When they are right growing becomes very easy...each element has a very important purpose and target range it should be in. They grow with just water and some nutrition. If these things are not controlled well, the grow becomes a lot harder to manage.