Answer: In my experience, it works best if the light bulbs are closer to the plants, say only an inch. (This is usually better for all seedlings.) Lettuce prefers cool temperatures, so you might try moving them to a cooler location. Also, the indoor lettuce is usually a cut and cut again type of procedure where leaf lettuce is planted rather thickly in a mat and cut back short (almost mowed off) when it reaches a few inches tall and then allowed to regrow. It may only be able to withstand this treatment a few times. Last, make sure you are not overfertilizing as this can cause weak growth too. I hope this helps you trouble shoot.
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