I plant a lot of trees throughout the year and the deep root pots can tend to get pricey when you buy in bulk and add on shipping.  I designed some custom pots that I could print and they are slightly more expensive than the bulk ordered pots but they are great when you only need a few dozen or less and come out about the same price.  

Since I designed them from scratch, I was also able to pick and choose various types of features from all the available pots in the industry and combine them into one for optimal root growth and handling.  These are designed for air pruning but can also be used as regular pots as long as you don't close the drainage holes on a flat surface.  

Containers are 200 mm tall (~8 inches)

• Stackable
• Designed for deep root trees such as oaks, chesnut, japanese maple etc
• Air Pruning
• Optimized to reduce root binding and circling

There are 4 wall thicknesses available in the file.  I wasn't sure which thickness was going to be the best.  The thinnest one I do prefer but if you're looking for something sturdier and don't care about print time go for the 2 mm thick.

I've printed mine in PLA.  I imagine they could be printed out of ASA, ABS or anything you wish for better performance.