This device keeps a "moat" of water around the base of a plastic bottle. You then place a string in the moat (or tie it around one of the "bridges") to provide a wick, which wicks water into the pot, keeping the soil moist.

Tested with Monoprice MP10 Mini.

Print the "Legs" upside down. I printed the water tray in PETG and the other two parts in PLA. The top needs to be some water-resistant material. The screw threads should accept most soft drink bottles.