This is a vertical planter. You fix a wooden rod (1.25 inch diameter) to the wall and then add as many plants to it as you like! Everything you need is included, except the screws (and anchors) needed to fix the rod mounts to the wall. You'll need the following:

• 1x 1.25" diameter wooden rod (does not need to be wood, could be made of any other material). The length is up to you depending on how many planter you want and how far apart you want them.
• 2x Screws (#8)
• 2x Wall anchors (for #8 screws, if needed)

When printing the supports, use 4 walls. For the pot, 2 walls is enough.

You can use smaller diameter rods down to about 28 mm (1.1") as the printed fasteners are long enough.

The inside diameter of the pots is 130 mm and the height is 127 mm.

EDIT: Added a print profile for longer fasteners for smaller rods.

EDIT #2: A new print profile has been added to print the inner pot that fits inside the plant pots. No need to look for store plants that fit, just use the inner pot to place your soil and plant. The inner pot has holes at the bottom for drainage into the outside pot's available volume at the bottom:

EDIT #3: There is now a horizontal version here: https://makerworld.com/fr/models/3494621-horizontal-pot-planter#profileId-3991435

Some screen captures to show more details: