Substrate for Developing Trees

[Africanherbman]

I've heard much about the ideal substrate for mature trees in their final pots, getting their ramification, but I don't believe I've seen much said about what to use for developing trees. Specifically I'm talking about trees that I'm just trying to thicken the trunks of. I think I've once heard Ryan Neil say for developing trees, he uses much coarser particle, buy I can't find that lecture or podcast again. What are you guys' thought? Particle size? Soil type? Pine bark? Pumice? Akadama? Any old soil?

 

[Firstflush]

There are a million answers to this. You want really good drainage and moderately rich.
You can use a good potting soil but add lots of perlite and pumice. I do the same with cactus mix and add worm castings and/or compost.

On a more recent trial I mixed cactus mix and potting soil but added a ton of perlite. Drains really good …so much so that irrigation water barely stands on the surface soil for more than a second or two before running through the pot.

 

[Colorado]

Pumice as the primary component. You can add a bark particle, clay particle, or some other addition if you like, but I rely on pumice heavily.

 

[Mike Corazzi]

Pumice as the primary component. You can add a bark particle, clay particle, or some other addition if you like, but I rely on pumice heavily.

Does that include the rounded hyuga also?

 

[Colorado]

Does that include the rounded hyuga also?

Never used it.

 

[Cambob]

I use 100% diatomaceous earth in the form of sifted NAPA 8822 for trees in pond baskets. Holds water surprisingly well, excellent drainage, and to say it’s dirt cheap is an understatement. It’s literally cheaper than dirt. Or at least cheaper than equivalent size bag of potting soil.

 

[Africanherbman]

Thanks for the replies guys. So what is the difference in properties you're looking for between substrates for developing trees vs for trees in their final stage?

 

[Gustavo Martins]

I use good quality potting soil for growth and trunk thickening. Later, when I move trees to large and shallow pots I use a mixture of coarse pumice, lava rock and Leca. I may also add a little of pine bark if necessary. My two cents.

 

[bonsaiDerek]

There are a million answers to this. You want really good drainage and moderately rich.
You can use a good potting soil but add lots of perlite and pumice. I do the same with cactus mix and add worm castings and/or compost.

On a more recent trial I mixed cactus mix and potting soil but added a ton of perlite. Drains really good …so much so that irrigation water barely stands on the surface soil for more than a second or two before running through the pot.

isn't potting soil just going to clog up a mix of perlite and pumice?

 

[Firstflush]

^^^It is actually increasing pore space and drainage. Keep in mind this is totally different than trees in later pre-bonsai and refinement stages where you want perfect substrate properties.