What is the dirt to mulch ration of this so-called premium top soil?

Hello Honestone, and thank you for your question. The specific make up of each soil type can vary based on product and raw materials in the manufacturing location. We strive to ensure consistency in product by producing and shipping the best materials to all of our production sites. Topsoil is primarily soil but can include some compost and/or wood fines. We hope this helps.