You said you will water them once you see some decent growth... how are you watering them now?

The seedlings don't need fertilizers or nutrients until they have about 4-5 nodes on them, then you can give them veg nutrients starting at 1/4 strength and gradually increasing.

Do you have any fan moving air around the plants and inside the cab? I know you don't want to buy things, but even a computer fan blowing between the lights and the plants will help with temps and strengthening the young ones.

From what you say, the seedlings could have died from heat, ph issues, or perhaps underwatering (this just came to mind because you said you would wait to water until you saw some growth...), maybe a combination of all of them.

Hope you get things figured out. Keep us updated :jointsmile: