I’ve got 3 seedlings under the light…Only this one has yellow leaves…She is a og kush auto…My last seed…I was thinking that I was over watering…Now that the soil is just slightly moist,I assumed the leaves would turn green…NOPE… What about nitrogen deficiency?? If so, would a little bit of coffee or used coffee grounds help with the problem…
Wait and see…There are times I have had the emerging leaves start out yellow and then the nodes greened. You can do an ammonia misting…read my Watch my Rules
@Wildbill it’s a rooting issue. The upper foliage is growing faster than the roots can support. I’ve had this happen a lot with seedlings. Either the lighting is off, something in the medium is preventing root growth, the vpd is off, or it’s being watered too often so the roots aren’t searching for water and it’s flushing the nutrients out of the root zone.
You can trim off the dead foliage so it can focus more on roots and the new growth instead of trying to keep the older growth alive that it can’t feed yet.
Mixing up some water and liquid kelp with some mychorrizae will help too and water with that. Make sure you cycle wet to dry as well even with seedlings. At this stage they really only need about 1 oz of water at a time around the outside of the leaves.
What are your temps and rh too just in case it’s vpd and not just a nutrient/watering issue?