I can't squat because of what I think are flexibility issues. When I try to get low my body either wants to go up on my toes or just fall over backwards. I have been stretching my calves, hams, glutes, quads the past two days and I hope this will fix the problem. My question is how many times per day should I stretch them, and how long should I hold the stretch?
read through Mike Robertson's articles. could be a strength issue too---you might have to start out doing single-leg bodyweight stuff and posterior chain strengthening.
Read Get your Butt in Gear parts one and two by Mike and Eric.
I have doubts that this is a flexibility issue, but are you going ass to grass, or parallel with the floor? Either way, do joint rotations head to toe, and light dynamic stretches (using the muscles of your body to lift the body part to your full range of motion, such as lifting your leg straight up in front/behind/side) and a combination of dynamics and static passive stretches (using your musles to support you in a stationary stretch, such as the front and side splits) after a workout and on off days. I hope this helps, and I hope I didn't confuse you too much
Oh! And hold your stretches for 20-30 seconds and repeat until you feel you've gotten to your full range of motion. These are static passive stretches of course. Don't do these before a workout, but afterwards.
IMO, the best way to build flexibility over a given ROM is to move in that ROM. Basically, do bodyweight squats. After a week or so of going as low as you can doing some form of rythm squats(Tabata, Hindu etc), I guarantee that you will see a huge improvement in your squat depth.
Put the bar away and just do them bodyweight. Maybe widen your stance a little. If you want to add weight, do dumbbell front squats.