June 15, 1998
Potting soil can be re-used from season to season. An exception would be any mix which held a plant with a distinct disease problem. A good practice is to empty and scrub containers, dumping the contents on a tarp before proceeding. Dump out the potting mix, fluffing it up thoroughly. Add about 1/4 by volume of perlite, vermiculite, or pumice to increase the drainage.