Low cost soil mix for fabric containers?
I am in the process of phasing out regular plastic containers for fabric containers. I have quite a few fruit trees and for the first stage I would need 200 gal of soil mix (fill in the 10 x 20gal fabric containers). The cost of a nice potting soil mix would be very expensive to fill in all the containers.
The big question is;
Could I grow healthy trees in a mainly compost mix 2/4 of coffee grounds and green manure, with perlite 1/4 and pine bark 1/4 ratio in fabric containers?
I was hoping the fabric containers aeration and design would prevent the mainly compost mix from turning to muck and depriving the plants of air.
Anyone have some advice or first hand experience with this?