Frank, add the following to any file in /etc/apt/sources.list.d:
deb http://ppa.launchpad.net/geany-dev/ppa/ubuntu raring main deb-src http://ppa.launchpad.net/geany-dev/ppa/ubuntu raring main
I don’t think there are any problem dependencies that would prevent the raring package from installing on saucy. Usually (though certainly not always) installing a package built for an older distribution than you’re running is trouble-free. At least it has been for me in seven years using Debian-based operating systems, where third-party packages tend to be built for either the current stable release (Debian) or the current LTS release (Ubuntu).
James