Municipal solid waste incineration bottom ash can be used in plant growing media as a substitute for commercial fertilizers. The ash contains helpful substances like calcium that can aid plant growth. Adding different amounts of ash to growing media increased copper and zinc levels in ryegrass and barley plants, but did not significantly affect their growth compared to plants in regular growing medium. Replacing natural sand with ash had a positive effect on the pH of the growing media. This shows that using municipal solid waste incineration bottom ash in plant growing media is feasible and could lead to more innovative ways of using this waste material.