Can you put a cast on a single toe?

No need for a. Cast, but "buddy taping" adjacent toes together is usually effective for immobilization and relief from much of the pain associated with a digital fracture.
Depends. Usually you do not put a cast on a single toe, but at imes you do cast/cast boot the foot to protect the fractured toe. This depend on a variety of factors. Discuss with your foot specialist. Dr l.