Not a copy of but inspired by parallelgoods' http://www.thingiverse.com/thing:903411 self-watering planter, I recreated the idea utilizing a wide mouth mason jar. This is the wide mouth, and won't fit into smaller mouth jars (Diameter is 3.25 inches)

Features small holes to keep roots moistened and half the printing material due to the utilization of the mason jar, or other cup with similar diameter. There is an arched off section which is used to rewater without having to remove the entire structure- there is a small hole to allow the water to drain into the mason jar from this port as well (pictured in the shot of just the device).

Thank you amazing people who made this thing! Thank you @fathergoat for some amazing feedback I added it to the description. I have not played around in cad in a while otherwise I would just update this bad boy.

For anyone having trouble with scaling, I scaled mine to the following values. Including both %'s and absolute values (in MM).

%:
X: 987.89
Y: 987.89
Z: 1000

MM:
X: 81.55
Y: 81.55
Z: 101.6

Scaling at 1000% across all axis made the insert far too tight in the jar. I was able to squeeze it in the jar, but I'll have to destroy the insert to remove it from the jar. Scaling the X and Y down slightly and the insert fits like a charm!

Also, the holes at the bottom of the insert did not print cleanly on my Prusa MK3S. I used a 5/32 drill bit to open the holes back up.