Update 19.05.2020
This is the big sister of this design: https://www.thingiverse.com/thing:2950840
I made it some time ago but didn't publish it yet because I couldn't manage to print it airtight reliably.
Now I am publishing it anyway and maybe someone else finds the right settings and can share them with the community.
This thing holds around 180ml of liquid so you have an increased time with no watering needed.
A Friend tried this on his tomato plant and it kept it moist for two weeks.
If you can't manage to print this watertight treat it with a layer or two of clear acrylic spray paint. That works very well and also hides the layers effectively. That leads to a better transparency.
When put on the table with the big side down it is also usable as a vase for one flower.
V3.1_Big_Plant_Watering_Ball_upright.stl | 3.7MB |