Thanks, all, for your comments. I mix my own potting soil and have, on occasion, blended in about 1/4 used soil. Seems to work just fine.
Gardener was the label imprinted on me when the souls were handed out and so be it. --Margaret Roach (Thank you, Sharon!) Notes from the Garden: Articles of interest on all aspects of gardening Cottage-in-the-Meadow Gardens: Come on in and take the tour! Check out the photos!
