When I first got into growing Chinese Elm bonsai, I made the mistake of using a generic bonsai soil mix that was too heavy on organic matter. I noticed pretty quickly that the soil would stay wet for too long, which led to some root rot issues. After some trial and error, I settled on a mix that really turned things around for my elms. I use a combination of 70% akadama, 20% pumice, and 10% bark chips. The akadama holds moisture and provides some nutrients, while the pumice helps with drainage and aeration. The bark chips add some organic content without making the soil too heavy or boggy.

Now, in the middle of summer especially, this mix has been fantastic. My Chinese Elms have thrived in it. They’ve been putting on good growth and the fine ramification is developing nicely. I water daily in this heat, and the mix allows just the right amount of retention while preventing over-watering problems. A friend of mine swears by adding a bit of lava rock instead of bark for better aeration, but I found that my trees prefer the balance this mix provides. If anyone else has tried different ratios or additions, I’d love to hear about your results.