exclude specific directories upon init or add

I'd like to exclude some directories in a project that only holds cached items such as auto generated image-thumbs, sql-cache etc, they are located in project subdirectory for project simpicity, (./sqlcache , ./tmp etc).

Is there any clever way I can exclude these directories, (I'm thinking of options in bzr init, but can't find any),
neither does bzr add --no-recruse help me since I can't specify which subdirs to exclude.

Thankful for any feedback on recommended solution in this issue,

Regard,
/teson