The best potting soil is a homemade or commercial mixture that drains easily. The University of West Virginia recommends packaged potting soil as best, since it can be used immediately without mixing and can be bought in plant-specific formulas (e.g. potting soil for cacti houseplants). If you mix your own, the university recommends equal parts garden soil, sand for drainage and peat moss to hold moisture.
About this Author
Josh Duvauchelle is an editor and journalist with more than 10 years' experience. His work has appeared in various magazines, including "Honolulu Magazine," which has more paid subscribers than any other magazine in Hawaii. He graduated with honors from Trinity Western University, holding a Bachelor of Arts in professional communications, and earned a certificate in applied leadership and public affairs from the Laurentian Leadership Centre.