A mix works better than either potting soil or compost on its own, soil ecologists find. Potting soil mixes often contain 20 to 33 percent compost, notes extension horticulture specialist George W. Dickerson of the University of New Mexico. Add 25 percent compost to vermiculite, peat moss and perlite for an optimal potting soil blend, recommends Ed Perry of the University of California Cooperative Extension.
About this Author
Rogue Parrish has written two travel books and edited at the "The Baltimore Sun," "The Washington Post" and the Alaska Newspapers company. She began writing professionally in 1975. Parrish holds a summa cum laude Bachelor of Science degree in journalism from the University of Maryland.