Rubber Tree Plant

Question

What size of a planter should I use?

Answer 1

Starting out you need something only large enough to accommodate the initial root system, depending on the size of the tree. Once it becomes root bound, you can then move up another pot size, but no more than two sizes up. These articles should help as well:
https://www.gardeningknowhow.com/houseplants/rubber-tree/how-to-care-for-a-rubber-tree-plant.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/growing-trees-in-containers.htm
https://www.gardeningknowhow.com/special/containers/how-to-grow-container-trees.htm