I'm not sure if it's been mentioned, but also should be noted to NOT overfill or pack your soil too tightly in containers.
Too tight and roots will struggle to expand. Too loose and they'll dry out.
Water should be able to flow through the containers fairly easily as well. Water should have a nice slow flow through the medium. It shouldn't pour out the bottom nor should it settle on the top soil and go nowhere.
Also, in early seedling/veg stage, less is more when dealing with water. Use minimal amounts of water and don't water until the soil is nice and dry. This will force the roots to search for water.
For nutes. Try using a kelp/seaweed extract with your water. Kelp is amazing for root health and development