near me dumps out their old starter mix/potting soil. They charge 20.00 for a truck load (you load). The tricky part is that it is mostly depleted. So this is how I revive.
5 gallon bucket old potting soil.
3 gallon compost
1 gallon of pine chips (free from rotten cut down pines, just scrunch it off the rotten tree)
1 gallon of crushed lava rock 3.50 50lb bag if you crush yourself (you figure it out). perlite sub.
A bucket of rabbit pellets mixed in. (rabbit poo)
Wrap in a thick leaf type trash bag and lay in the sun for a week during the summer (kills bacteria, molds, seeds
etc.) If you have piece of silver colored tin you can cut that down to two days by throwing the bag on top of the tin.