Latt
If I had a feeling about seedlings not coming up, I would do something so as to figure it out.
In the past I have had small areas in beds that did'nt come up from slug damage. I have also had damping off in two beds.
I would not be able to sleep until I found out the problem.
I would start out with a section of bed, maybe 2'x2' or 3'x3' and start peeling the leaves off very carefully by hand.
If you notice alot of seedlings that are starting to emerge, then cover them back up and wait.
Slug damage: the seeds will be cracked open but will have nothing sprouting out. The slug will suck as much of the pulp out as it can. the pulp will not be out to the edge of the crack, but the pulp will have a concaved shape between the husk crack. Note: slugs will only eat what is above soil level, not what under the soil.
Damping off: Can have alot of different signs. The rootlet can turn brown to black. Or the seed itself will be rotten. cut open to check interior. Usually the seedling starts to sprout and then is atacked by one of several diseases.
Mice problems: are usually easy to identify. If you find empty cracked open seed shells under the mulch, its mice.
Not fully stratified: See post by Guy. He has pics that show the embryo and what they should look like in the spring.
www.wildgrown.com/index.php/Ginseng-Foru...d-on-emryo-size.html
Hopefully with some inspection under the mulch, you can come up with an answer of why they have not come up.
If it was me I would want to know. I have learned some things by doing inspections. I can't stand not knowing.
Good Luck.