Well, if you have no battery or electricity, you can tune with a tuning fork. Usually it is set to A 440 Hz.
Most people have no idea what that means.
Are you recording and are you tuning to Standard Tuning?
WHY would you do alternate tunings? Find out in my article about alternate tunings where I discuss the songs, ‘Burden In My Hand’ and ‘Pretty Noose’ by Soundgarden.