The last post in this category was from September 2022, when I got some clay balls and was excited to try them out. That was disastrous. I’ve snarked much in the posts since about how bad that was. Every plant that got the mix struggled (except the Black Locust, which has a deep pot that maybe let the clay balls work), and some died. Some I repotted into my new mix, where they flourished.
My new mix is:
- 4 parts perlite
- 4 parts pumice (14 mm)
- 4 parts scoria (14 mm)
- 1 part charcoal
In general, every tree I’ve put in this soil mix has thrived. The exception was the water gum, which seems to need lots of water retention – so much that it’s happy sitting in a tray of water e.g. as if it was next to a river.
But in addition to letting trees grow more, I’ve been surprised to find it lets them grow longer.
This was taken on the 9th April. Summer is over, and the temperatures are hovering around 20 degrees, with occasional mid- to high-twenties.
All of the deciduous trees in the stonier mixes are clearly slipping into winter hibernation. (Only the junipers are doing anything like thriving.) But all the trees in the new perlite/pumice mix are still growing strong. The fig trees at the end of the bench above are still sprouting new leaves. I moved some into a sunnier part of the yard so they’d get as much sun as possible.
I suppose I should note that the bottle tree on the ground behind the fig, the maple tree on the left which you can’t really see, and the bamboo on the right are in organic soil and are also still in growing mode. But they aren’t in bonsai pots.