This is my first design of a "Self Watering" Planter.

The planter is 8 inches in diameter with 5 mm walls for both the pot and reservoir. The overall height of the planter is 7.5 inches, with the reservoir having an internal height of roughly 30 mm and the pot having an internal height of roughly 142 mm. Also the pot has 5 "legs" that extend into the reservoir, having internal diameters of 25 mm and heights of roughly 35 mm. Using the dimensions listed, you should be able to calculate how much water the reservoir can hold and how much plant medium the pot can hold.

The pot "legs" have several 2mm holes for drainage and water absorption. The larger pot base has several 2mm wide by 15-17.5 mm long slots for drainage as well.

The reservoir has 4 partial circle extrusions for the pot legs to sit in to allow the pot to be centered in the reservoir and not move around. There is a roughly 5mm gap between the outside bottom of the pot and the top outside wall of the reservoir to see how much water is in the reservoir. Also there is a larger circular 4 mm window on one side of the pot to allow for watering from the bottom and viewing how much water is in the reservoir, in case the 5mm gap is no large enough.

I designed this planter entirely for my own desired specs and functionality, although please comment if you notice any flaws in the design or functionality of the planter. I can upload fixes or alterations if the suggestions would improve the functionality of the planter. Specifically I am concerned that the 2mm drainage holes and slots may be too small, or that the 5mm walls may be thicker than they need to be. Also, there is no gap between the pot "legs" and the reservoir extrusions, so depending on the tolerances of your 3D printer, you may have to sand down the outside of the pot "legs" or the inside of the extrusions of the reservoir. I can upload a file of the pot with the "leg" external diameter decreased by 1mm or so if people comment about having issues.

I have not printed this planter yet, but would presume the print settings would be similar to other water tight prints you can find. That being said, I presume the pot will require print supports, and plan to print the pot legs down and the reservoir bottom down as well. I can try to post settings once I have printed it myself or if anyone else prints it and comments suggested print settings.

This planter can most likely be scaled up somewhat since the drainage holes and slots are fairly small, but I would recommend not scaling down since the drainage holes and slots would likely become too small to non-existent. Please let me know if you would like me to design and post a smaller version with a similar design.