EDIT; New Version coming in Spring. I want a design with hexagons instead of triangles inside, giving the Racks more stability and a more 3D printed look to it. I want to reduce print time by reducing the volume of the connection area. Maybe i try a version without screws and using some support instead. But only if its not taking longer then current version. (2 Screws don't really hurt do they?)
Also i want to design a round version and different sights and diameters by using parameters.
If you have any ideas, let me know!
EDIT END;

I wanted to hang my plants with the pot onto my balcony railings so i can relocate them individually.
So i designed printed these pot holders. It was important for me, to get as much air to the plants pot as possible and make the mount really easy.
Your railing needs to be round with an diameter of about 40mm. The fence underneath it should be almost even with the railing, so the basket gets something to hit on. If it's not, the basket will sag a little bit. Maybe that would look not too bad?
The gab between railing(axis) and fence should not exceed 110mm.
I added a picture of the 3D model of my balcony railing, in order for you to understand wether u can use this thing or not.
Any Pot 100x100mm (D=100mm for round pots) should fit.
You will need 2x M3 screws and nuts. l=10mm and l=16-20mm. You probably have those for your printer anyway.

Let me know if u need any modifications. sadly i am to dumb to use openScad.

Make sure to use a temperature resistance material. PETG/ABS should do. I used PLA. Look what happend in the last picture. If you can use only PLA, make sure to use white. It will reflect more light resulting in less heat. I have several of these in PLA and all bent a little, but not jet the white ones. They might get destroyed in future by sun and wether but time will show.