Peat moss pellets are great for starting seedlings, so I made a small tray that is printable in vase mode with 0.6 or 0.8 nozzle. Just set the external perimeter to 0.9mm.

As I was printing the first versions I did not account for expansion of moss, when it gets saturated. So it is normal that the peat moss tablet sits loose. A byproduct of such an experimentation is also that TP cores fit into these. 

Perhaps it would also be feasible to germinate seedlings in these too.

I'm enclosing the OpenScad file I used to create these. There you can modify how many pairs you want, and also width of walls and thickness of bottom.