sylvestris
Do you have any questions. To the best of my knowledge, too much light wont cause curling leaves, and I have never herd of too much light using florescent
lights. Possibly too much heat, but I'm sure it would have happened before you raised them. The temp at the plant canopy (tops) should feel about 80%-85% depending on the type of plant, and probably about 75% for lettuce. What type of plants are they (I don't remember if you mentioned that before)?
If the leaves are curling abnormally, I would wonder if the
nutrient solution is too strong (especially for young plants).
1. Are you mixing the
nutrients full strength?
2. Is there any discoloration on the leaves?
3. Are the edges of the leaves turning brown?
4. What's the pH of the nutrient solution?