Stack-able seed planting pot

I made this pot to plant seeds one by one. Using it for dates currently. Their roots get deep so that is the reason for the shape. Would be good to have it in customizer scad format... one day i will learn that :)
One pot is about 23g and prints under one hour.

Update 2017.06.30:
Summer is here and pots are outside. They get direct sunlight for a few hours every day. Some of them melted a little :) but still holding up. Impressive from PLA.

Update 2016.10.24:
Added a little chamfer to the bottom so if you have leftover from brim or not-so-good looking first layers it will not prevent stacking. Tolerance is 0.2mm ad it works OK for me.
I made 6 pcs and it fits thigh when multiple pots are sliding at once.
Might be good to add +0.1mm to fit more easily.

Update 2017.02.13:
Dont be afraid of PLA composting too fast! Over 3 months now and single walled pots are still holding up. See last photo (With LED lamp :) )