It's a little hard to tell from the pics, but it kinda looks like they have been getting
over-watered or not drying out enough between watering. Are you Feeding them nutes Already? If So Personally I would Let them dry out pretty good just not to the point they droop tho. and when you water again try just plain PH'd water it may help. At this young stage they do not need much food. Hope this helps!! good luck and any other ?'s dont hesitate to ask 👍