Need well-draining mix, limited to Big Box store supply
I recently acquired meyer lemon tree, which requires better draining soil than the stuff I use for my herbs. :)
Unfortunately, I don't have a car and my only real option for soil is the local Home Depot. I looked for the ingredients to do 5-1-1- myself and it doesn't seem to be a go - I can't find everything, and what I can find is in such large quantities it may not help. Similarly, I can only get fafard online, it costs an arm and a leg (like three times what it apparently costs at nurseries), and it isn't the heavy material versions.
So, sacrificing perfection to be able to repot this sucker, is there a way that I can mix some of the more commercial options to come up with something decent for draining? I plan to wick as well to help.