Tuning a guitar without a tuner is a valuable skill for any guitarist to have. It allows you to keep your guitar in tune even when you don’t have access to a tuner. There are a few different ways to tune a guitar without a tuner, and the most common method is to use harmonics.
To tune a guitar using harmonics, you will need to pluck the string at the 12th fret and then lightly touch the string at the 7th fret. This will create a harmonic that is one octave higher than the open string. You can then compare the pitch of the harmonic to the pitch of the string that you are trying to tune. If the harmonic is higher than the string, then the string is too loose and needs to be tightened. If the harmonic is lower than the string, then the string is too tight and needs to be loosened.