Have a look at: http://geany.uvena.de/manual/0.14/index.html#build-system
I don't know Fortran myself, but Geany doesn't support smart compilation or debugging (apart from a plugin for GDB, which I guess doesn't support Fortran). Someone was working on a CMake plugin, but I think it hasn't been released yet.
I checked this and it all sounds very interesting. But.
1) When you/I use modules in fortran, then the order in which the source files are passed to the compiler does matter. This means that the classic way of writing a Makefile is not so easy anymore. There are tools like "makemakefile" that can check all dependencies in your sources and use this knowlegde to make a universal Makefile for you for the generation of .o-files associated with any source file in that directory, but then Geany should do the talking to this tool for me...
2) To tweak an interface between Geany and gdb for debugging modern fortran code is beyond my expertise. Particularly if it is not (yet) clear if gdb and g95 like one another. It is access to the debugger that I really miss in all (other) applications, so for me this is the ultimate bottleneck. If someone who has done it before (i.e. link Geany to g95) now stands up, I'll embrace him/her cordially. Otherwise, I think I'll wait and see what will come up in the future...
Regards,
Arjan