Look at the taco's of your top leaves on your plants, which is usually caused by only a few reasons. Your lights look a little close for those young plants in 1 gallon pots in veg. I would raise your lights to reduce light stress on your your plants and find a watering/ feeding method that reduces how often you may be watering/ feeding them...they do look a little overwatered. If you do this I think it will help you.
…and, from what I remember about growing in this live soil medium, it suggests feeding from the bottom of the bucket with water and use occasional top dressings, especially later in flower, and teas to help it finish...ambitious of you on your first grow. Good luck.