I just purchased my first bonsai tree. The kit I purchased came with a small green packet of coarse sand-like material (see picture below). In all my reading, I haven't been able to figure out what this is. Can anyone shed some light on this?

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  • Did the kit come with any instructions? – Niall C. Dec 12 '14 at 18:40
  • @NiallC., no, I wish! It was a fairly inexpensive kit at a chain store in Spain. Based on my reading, I have two guesses. #1, it's some type of fertilizer, or #2, it is used to grow moss. I readily admit that my guesses are unencumbered by knowledge :-) – James Hill Dec 12 '14 at 18:44
  • Whatever it is, it does not look (to me) like glauconite (commonly known as greensand) despite being green, and sand-like. – Ecnerwal Dec 12 '14 at 21:26
  • Does it smell slightly like a matchhead? – J. Musser Dec 12 '14 at 22:39
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    @Shule, GREAT question. I should have thought of that - water soluble would more than likely indicate a fertilizer. Alas, it is not water soluble. When I watered this morning, I put a tiny portion in the corner of the pot to see if it begins to grow moss over time. – James Hill Dec 13 '14 at 10:38

It rather depends if any other soil like medium came in the kit, separate from this material, and whether the bonsai pot could have contained all this material once the bonsai plant was wired into place. If it was a cheap kit, it's unlikely to have included kyodama or akadama, but this material might be a substitute for those, particularly as its coarse grained. Quite why it's green I've no explanation for, other than perhaps it might be thought to be more aesthetically pleasing, but I strongly suspect, if nothing else was included, this was supposed to be either mixed with loam or used alone as a planting medium.

UPDATE: My apologies for not explaining more clearly. Your comment really made me smile, thanks for that... Kyodama is a bonsai soil, used alone or mixed with other soils; its a specialist bonsai thing, is gritty but retains water, and its origins are volcanic. Akadama, also known as red clay, is a naturally occurring, granular clay like material which also provides very good drainage yet retains water, all good things for bonsai growing. Often, the two are mixed, maybe with some loam (think John Innes composts) to make an optimum growing medium for bonsai plants. Bonsai plants are usually wired into place inside their container, then the planting medium is poured around the roots - there is no expectation that the roots will be solidly retained by the planting medium, rather, that they can root into it if they want to (and they do, to an extent) but it provides a medium which carries water and nutrients (which you need to add from time to time) to enable the plant to survive and grow. So I'm saying it might be that the 'green sand' you've got there is a substitute for 'top dollar' bonsai soil, or meant to be mixed with, say, multi purpose compost to make it coarser, more open to air, and suitable for bonsai growing.

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  • Thanks for your answer. I'll be honest, I understand almost none of what you said. Since I'm new to bonsai, I'm new to the terminology also. – James Hill Dec 13 '14 at 12:38
  • @JamesHill - see updated answer – Bamboo Dec 13 '14 at 13:06
  • I wonder (based on this) if it might be sand, coated with some green polymer to help it hold a bit more water in order to mimic the behavior of the described materials. – Ecnerwal Dec 13 '14 at 21:27
  • If I told you both that the tree was pre-potted when I purchased it, would you still think it was for potting? The kit came with the tree, already potted, the bag of green sand and three small stones :-) – James Hill Dec 13 '14 at 21:39
  • Ah well, there you go - you didn't describe the contents of the kit, and I did say at the start of my answer 'it depends what else came with the kit'... so perhaps its simply meant as a kind of decorative topping for the existing potting medium. I could have saved myself all that typing! But perhaps it was of interest anyway... – Bamboo Dec 14 '14 at 11:39

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