Tar a folder without .git files?

Simplest answer: Add --exclude-vcs. This excludes all version control system directories

Personally I use

tar --exclude-vcs -zcvf foo.tar.gz ./FOLDER_NAME

so all you need to do is add the --exclude-vcs at the end of the command.

Have a look first at git help archive. archive is a git command that allows to make archives containing only git tracked files. Probably what you are looking for. One example listed at the end of the man page:

git archive --format=tar --prefix=git-1.4.0/ v1.4.0 | gzip >git-1.4.0.tar.gz

If you want the archive to include the files tracked by git, but not the git repository itself or any generated or otherwise untracked file, then use git archive.

If you specifically want to exclude .git but include everything else, under Linux or FreeBSD or OSX or Cygwin, tar has a simple option to exclude a directory:

tar -c --exclude .git -f - foo | gzip >foo.tgz

With GNU tar (i.e. under Linux or Cygwin), you can shorten this to tar czf foo.tgz --exclude .git foo.

The POSIX way of creating archives is pax.

pax -w -t -s '!.*/\.git$!!' -s '!.*/\.git/.*!!' foo | gzip >foo.tgz