I guess my main question is if the chunks are too big.

Gravel does little for the plant.

The function of the soil is to provide water to the tree. Also, it holds fertilizer while the tree transports water from soil to leaves.

Gravel does nothing to hold water, no matter how large it is. In the traditional akadama/pumice/lava rock mix all three components soak water up like little sponges. The expanded shale I use does that, as do the coffee grinds.

Si wrote:

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.

The sun heats the pot up, and plain ground clay from the ground solidifies and makes a hard mass that water doesn't penetrate and that roots have a hard time penetrating. Here in the southeastern US there is a layer of loam over clay and some plants penetrate the clay with a long tap root for stability but they depend on the layer over the clay to survive.

Akadama is hard baked clay dug up in Japan, baked there, and shipped here. Some people use it because it is Japanese, but it is pretty expensive. Others use other similar products that have similar water absorbing qualities. Some people use kitty litter, because some brands are just baked clay. If you try that you want to get a brand without deodorants or other additives. Would used kitty litter have good fertilizer qualities? Hmmm.....

A few things I am observing here.

You talk about collecting yamadori, but then you come with these small containers. TO me that is an indication that either you are not collecting yamadori but are pulling seedlings from a yard, or you are missing some information on how to establish collected old trees.

Do you have some shots of the trees you are collecting?

As for substrate.. Get rid of potting soil etc. You need to have a fairly coarse mixture, and, more importantly, ideally somewhat even granule size. Potting soil normally is compost, which will fall apart fairly quickly.

Before typing a book:

Yes, what i have are seedlings. I thought yamadori just meant any tree you collected. i did use the potting soil, but will use the things you use in the future. thank you for the video, that was very helpful.

here are the tree pics


the order from top to bottom is
fir
spruce
spruce
red pine
spruce

they are frozen right now, but will thaw tomorrow.


here is the other tree i repotted with that mix. i have been caring for this ficus ginseng microcarpa for a year now and decided to repot it because it was in a pot that was way too small for it and it was in 100% compost with a little bit of perlite. I got it a pot that is the same depth as the thickness of the trunk. Which side do you guys think looks best for the front?


Personally i like the first image. also don't worry it is kept inside

That is some view you have there.

Will not select a front on your ficus as I in general do not like these ginseng ficus'

Yamadori is a word that conveys a sense of age, or struggle of a tree shaped by natural forces ANd although they can be small, typically these are decades in age. MOst literal translation is "taken from the mountain" afaik.

I did have one more question. I collected some trees last year and put them in a regular potting mix, not knowing about bonsai soil at the time. they are not doing very well. Should I repot them this potting season?

If the roots are the cause of the problem, I would.