Under-plant evaporator

This plant saucer insert allows having a water reservoir under a plant that slowly evaporates. This is good for plants like begonia that prefers a higher humidity than is found in most homes, especially in winter. Put one of these in your plant saucer and your plant on top, then fill with water. The outermost ring has a hole that allows for easy watering.

The design is a bit hacky, with not-quite-perfect angling and the customizability not guaranteeing a solid outer ring. Working diameters are (roughly) 105mm (two circles), 140mm (three circles), 175mm, etc.

Possible improvements include designing the supports such that they use surface tension to draw up the water and make it evaporate faster, properly aligning the rotated supports, and making the cut-out for watering be more precise.