Super small Bonsai are doable. I used to love doing them.
Use 1/10" soil mix with some fine mulch for moisture retention.
The link below has some…
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Grew out of it. Mostly 10- 36" bonsai now.
Expect frustration in keeping the above size potted tree alive though. I used to put them in a cool terrarium over winter, they never seem to be able to take the cold, 15F, winter dessication. Although, in Simi Valley, Ca. you should have better weather…
I usually start with a seedling or cutting slip. Clip n grow. Very little wire.
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I suggest you start companion plants in the smaller pots. Mosses, grasses, sedges, mini flowering plants, and succulents. Much more rewarding.