How many plants in a 22 inch wide container?

[gorbelly]

Depends on the varieties, whether or not you plan to prune, etc.

If you want to grow a big indeterminate without pruning, just 1 plant.

But a couple of compact or dwarf indeterminates (meaning not the micros but something that tops out naturally at 5 feet or less) or determinate plants would do fine in a container that size without much pruning, IMO.