Often gardeners will notice that the first set of leaves, known as Seed Leaves or Cotydelons have turned yellow, dried up, or even fallen off.
This is no cause for alarm.
The job of these leaves is done, and as long as the rest of the plant remains healthy, there is nothing to worry about.
For some plants, typically for tomatoes, the bottom leaves are removed before planting anyway.
If the leaves continue to turn yellow and fall off, then there is a problem. Most often this is from over watering. There was an elderly Botany professor we knew, who used to always say:
“Plants love to get their faces washed, but they hate to get their feet wet.”
For seedlings, this means not to give them too much water. When they are young, keep them just moist but not wet. You should be fine.
4 Problems to watch out for when starting seeds