Greetings,

I am considering buying a soil mix of equal parts: Black Lava, Coarse & Fine Pumice, Calcined Clay, Coarse Vermiculite, And Organic Compost Soil, for my ficus I bought last spring that in regular potting soil. I have picked out a suitable clay pot (same depth as trunk width.)

Another option is I mix up the soil myself using : vermiculite, perlite, sand, fine gravel, and organic soil in an equal ration.

Can I use either the bought or made up soil for spruce and hawthorn yamadori collection? I have some 3cm depth pots, and some elegant curved trunk trees on my property 10cm and below. I live in a humid environment and am gearing up for yamadori season once the buds start to swell.

Any thought would be much appreciated.

Cheers,
Si

Any of the soil mixes you suggest will be fine. The trick is to adapt watering to soil and climate, not adapting soil to species.

Myself I am not found of perlite in my mixes as it is very buoyant and often ends up on the top. I am also not happy to use sand, too fine and risks to decrease drainage when settled.

But those are just opinions. You need to create the mix you are happy with.

Thank you for this! I also find the perlite constantly floats to the top, but i think enough of it stays in the soil. I think I will try a 4 part ratio: vermiculite, perlite, regular potting soil and gravel.

Does the gravel have to be fine? or can i use like 0.5cm chunks?

You can use any graven of your choice. Just stay away from gravel which is high in lime for acid loving plants.

Another question I had is can I add used coffee grounds and peat moss?

Yes you can. You can use everything that is not toxic to your trees as long as it fits your care.

I am not a fan of small fractioned organics in shallow containers. So for that sake peat and Coffee ground is not for me. However, I grow a lot of trees in development in big pots. The acid loving trees have a lot of peat in the soil.

The standard mix is 1/3 akadama, 1/3 lava rock, and 1/3 pumice. I know nobody who uses this. Everybody adapt to their own mixture and the trees all do fine.

I use expanded shale from a local building supply company in place of akadama. Why buy clay from Japan and pay shipping? I save soil from repotting, sift it over the winter, and mix it with the shale next year to get a good balance of draining, then mix coffee grinds to get organics to hold more water, which is important in the south east US where we get so much sun.

The one thing you have to worry about is drainage. If you dig something up with roots stuck in clay you have to worry about drainage and having the sun cook the clay to the point that the roots can't penetrate it.

If you get something that drains real well you also have to fertilize weakly very often, because the fertilizer drains off as you water. Almost everybody figures all of this out, and almost every tree is tough and figures out how to overcome our errors in soil.

Good luck.

Thank you for this. I figured not many people used the recommended mix. I think my mix will be equal parts: vermiculite, perlite, houseplant potting soil, fine gravel, peat moss, and a few tablespoons of used coffee grounds. I think this will be my mix. Everything I can get locally.

These are the pots I have. Most of them are dishes I have drilled holes in or will drill holes in.

The ground here is mostly clay, so should I mix a bit of that into the soil? How much? I will get it down to the bare roots, and mix some clay in.

Thank you both again.

Regular clay is one of the few soil components I would advise not to use. It really destroys drainage.

Is this an okay mix of gravel? The biggest chunk I found was 1.5cm, and it goes all the way down to sand size. Just stuff I found on my driveway.

I rinsed it thoroughly.