Answer: Sounds rather perplexing. It's probably a reaction to the intensity of the light, and the tender leaves have become "sunburned". Six inches is a good height for the light - have you been turning them out at night? Seedlings require about 14 hours of light each day. Have you fertilized? A diluted liquid houseplant or Miracle-Gro solution should be given in place of regular watering about every two weeks. Try adjusting the growing environment with the above suggestions and see if that doesn't make a difference in the appearance and performance of your lettuce.
Q&A Library Searching Tips