Adding nutrients to your water is important. You want to spray your plants with the water/nutrient solution. Keep the plastic dome humid, though there should be a few holes poked. Air circulation is important to prevent rot/mold. You can still save them, I do sugget investing 40 dollars on the system I made for myself. It is the most accurate I have used and the most efficient and you wont have to kill any plants

The plants would be better off staying under 24 hours of light. Plants use the nighttime to put their nutrients back into the roots for root growth. You have no roots, meaning they have no need for night.