Printed:

•  on the side, so the top view would be an upper case L
•  with supports and a brim for maximum efficiency
•  20% cubic infill 
• and 0,2 layer height
• everything else was pretty standard. 

Used some removable command strips to hang.

I got my 3d printer because for the longest time I wanted some mini shelves like this to place my plants in the receded wall area adjacent to my window. 

And so these were my first prints!

Maybe there's some other person with the same issue who will find these useful…

Probably black PLA might not have been the best choice to hang in the sun but they have ben app for a couple months and we'll see how they'll fair in the summer.