Bonsai Soil All Purpose Mix | Fast Draining Pre Blend (2 Quart Bag) Plant | Pumice, Lava, Calcined Clay and Pine Bark ● Potting Pre Mixed Bonsai Plant Soil Mixture By The Bonsai Supply

Safest and least trouble is a premade mix. I have heard this stuff is good - https://www.amazon.com/Bonsai-Purpose-Draining-Calcined-Supply/dp/B07M68B4JG/ref=sr_1_6?crid=2LTBMC1WMT701&dib=eyJ2IjoiMSJ9.Cg4cFoA5ta_zK_2zUHhBahA3Q9Rsf8cgtpLwcNaZZJGGjPHdHNx6wn5vDq9YPX9PhLtY6DwJLS4mymQpAVk4_ozjEylb_BTkLhnF_EIbjQkphS3kfgZxbb3EAYcb2UreEu_ys_PAJxtV2DlLQhXcNlNOd7pSKBEtFNTUXNqgxJc0fstThOs0g35pBd6VS35mniMo8Hz1CipUuCA_OTChye7WX9MR_--JbOcoN__osG3MpV4EwnhBFI1l6cS3LoKXRes4GKm9vg01AJ_7cngkn_QJYGFS9D8vpQUhU11NgW4.1zYM6HErxwKQtk-rN3djGqhgPCtPkwLZB9sHG5jWeYk&dib_tag=se&keywords=Bonsai%2Bsoil&qid=1781316844&sprefix=bonsai%2Bsoil%2Caps%2C250&sr=8-6&th=1 If you want to make your own there are many different recipes, depending on what you have access to and your budget. Most common professional recipe is 1/3 lava, 1/3 pumice, 1/3 akadama. Unless you are doing a lot of trees it’s hard to beat the premade off Amazon.