This is a half-flat lettuce or petuna starter tray.  It has a few hundred drain holes and the sides are corrugated to make it keep its shape when vase mode printing.

Print it hole side down, make the bottom 2mm thick with bottom layer count (for .2mm, that's 10 bottom layers).  Doing this gives it stiffness.  Then slice that as a vase mode print and you're off to the races.

This is the exact same model as the resizable seed sprouter cover that I have - but turn it upside down and fill it with good soil, put it in a pan of water or seed starting tray, and you'll grow lots of lettuce or flowers.  Easily resizable to get even larger planting pots.