What size pot do I need for a tree or large indoor plant?

For floor plants and small trees, reviewers gravitate toward 20–22 inch diameter planters with at least 18 inches of depth. The SnugNiture 22-inch tall set and the Veradek 30-inch tapers are both sized for that use case; the smaller 8–12 inch self-watering pots in this roundup are best for tabletop tropicals, herbs, and starters.