It is my approach to tell students to not touch the tuning pegs in the beginning. Everyday in class, each student plays their open strings from the floor to the ceiling, first through sixth, in quarter note value. After several weeks of tuning each guitar, students start memorizing the sound of each string. At that point, I tell students which string to adjust and which direction.
I have tried putting an electronic tuner on each guitar. That does not work all that well when students try tuning an octave too high too low. Most students now have an app on their telephone with a tuner.
Overall, I would not encourage tuning until perhaps the second half of the school year.