I would replace them. Anytime that happens to mine they have not recovered. Probably some bug ate the leaves.

I find it much easier to direct sow or start MG seeds in pots. I just soak them overnight and most sprout within 3 days of being planted.

Hi theartist - The 1st set of leaves are the cotyledons aka the embryonic leaves as these are present in the seed embryo...the later leaves that are produced afterwards are called the true leaves...

The cotyledons contain a store of nutrients (functioning like a type of retained yolk) that the young seedlings draw upon to help get them going before the new leaves take over the main energy producing functions...

Seedlings which have lost the cotyledons can often survive , but they usually need to watched , making sure that they have good sun and water eventually slowly producing true leaves...after the true leaves form the plant will grow much more rapidly...although many plants which have lost the cotyledons may not develop quite as fully as plants which may shed their cotyledons naturally...

The seedlings of particularly rare types would usually be nurtured despite having lost any cotyledons , but if the types are very common , then you might be better off starting some new ones that retain their cotyledons...

Hope that helps...

TTY,...

Ron