The leaves of tomato seedlings are yellowing

The leaves of my tomato seedlings are yellowing. What might cause the problem? How to solve the problem. Can I transplant them now or should I leave them in the pot until they become stronger . Thank you.…

Browning tomato seedling leaves

What could the problem be? These seedlings were fine until a couple of days ago although one seedling shrivelled up and died. Now, all my plants seem to be affected as well as the peppers. Some of the leaves are…