Are they clones? the bottom leaves from my clones did this too...
I hear its almost normal...
My guess was the plant was using all the food from those leaves helping the root system progress
John Doe Reviewed by John Doe on . All seedlings are yellowing I can't figure out what the cause is. All my seedlings have yellow leaves. I know it's not the soil because I've used it before, and I'm using 2 different kids of soil and all my plants are yellowing. I have a 600watt light on them, and I wonder if it's too much. It's about 2 or 2.5ft away from them right now. I think maybe I am underwatering? Rating: 5