I've designed this cover for the modular compost bin (https://www.thingiverse.com/thing:3485255) so I can adjust pots with tomatoes or directly tomatoes in the compost, so the worm feeds the tomatoes directly. I'm planning to use it with tomatoes, pepper, maybe melons...
Print instructions are easy, you have to print:
2 x 1-left.stl
2 x 2-right.stl
2 x 3-center-left-right.stl
1 x 4-center-center.stl
Use 3 M4 x 10mm and nuts to assemble the center support and 8 for the rest are optional!
I've used FreeCad to design all parts, and printed on an Ender 3 using Cura.