I am using rock wool as a growing medium. Yes, i am using Growell Nutrients to grow them. Not exactly full sun. What do you mean by What size are the seedlings ? I place 3~4 seeds in one rock wool. A little worse than the picture, shrink a lot more.

How many sets of leaves? Can you post a picture?

Do you know the pH of your nute solution?

PH for the water is around 6.2

That seedling is fine. Mine look just like that before I put them into my res. They lie down like that then they perk up when they go under the lights.

I have nothing to say about them growing fine and then suddenly dying. I have no clue why that would happen.

Are you planning to move them into a hydroponics system?

Edit: I really don't think you need nutes for lettuce sprouts/seedlings. Someone else can chime in if I'm wrong. For me it's just rockwool and tap water until they're ready to transplant. My seeds usually sprout within 36 hours.

I had this happen to me too when i was growing lettuce and then after a few day in the hydroponics system they started to look alot better the more sunlight they get the better. if your interested check my channel out https://www.youtube.com/watch?v=Q3yCuqXhOHw

hi guys can some one help me as how much i need fish to put in my aquaphonic systme about 10 galon and if the is a formula for