Dolley, Do you have a vocational school near by that has a horticulure class? They may make your garden a class project at little or no cost to your facility! Or a local garden or rose club may be willing to provide some "cheap" labor and cuttings.
Maybe a carpentary class or wordworking class would build you raised carts or gardens for wheelchairs to roll up to to do your own gardening. The student nail stylists' also need hands (and feet) to practice on, I've had a group come in and do manicures for free or for a snack with the residents. Invite a local high school debate team to debate a couple of your alert residents for a week-end activity, keeps everyone sharp! Gayle