I Thought It Would Be Cheaper

My tire garden isn't as cheap as I thought it would be.  I knew the shredded leaves and wood shavings would compress as they decomposed, but I really thought it would be slower.  I keep having to buy more potting soil, rip the strawberry plants out, put more potting soil in, and replant the strawberries. I think eventually I'll be finished with that, but not yet.