I too have used Park Starts and other similar systems. I found them convenient, but balked at the price for refills. A couple of years ago I experimented with the foam blocks the "wedges" are to fit. I poked a bit of sphagnum moss in the bottom of the holes and filled them with regular seed-starting medium and planted as usual. It worked perfectly. I didn't have the problem mentioned by another gardener of the wedges being too tall for the transplant pots. This works so well for things like lettuce and other greens that it is the only way I now grow them. Sonnie