This is my first year using kanuma for this azalea, and I’m noticing something very strange. We had rain the last few days, and today got below freezing. The water freezing in the pot appears to be lifting the kanuma up - at least on the top layer, but perhaps all throughout the pot.
I’ve never seen something like this before. My theory is that it has to do with the lightness of this particular substrate, but it’s not SO much lighter than other substrates I’m using that I’d expect to see this degree of effect here and NOTHING on other trees in similar conditions (as is the case). Anyone have experience, tips, or thoughts? My gut says this level of soil disturbance cannot be good for the tree, regardless of what’s causing it.
Its not a bad line of thought but I immediately wonder how much heavier is pumice or lava in relation to expanding ice in a container? I could imagine this happening with either of those particles as well but purely a thought experiment. Perhaps its lack of weight doesn’t allow it to fall back into the spaces once taken by the ice during expansion? I wish i had some clue but I dont, figured I would toss this up as a way to encourage a better/accurate line of thought?
I did some more research and apparently it’s quite normal, even with other substrates…?.. at least going by some old Bonsai Nut threads I found. In that case, I’m just surprised I haven’t seen it before now. And I’m still not seeing it in my other trees, even the ones in pots.
Maybe you’re right about substrate weights, and it’s more to do with the size of the container or the amount / percentage of water in it at time of freezing?
Mixed thoughts in those threads on how bad it is for the roots though, which is the important question.
I would imagine the difference of how bad it was for the roots has nothing to do with particles moving but rather the “bad ones” were actually situations where the roots where left in conditions to freeze. Obviously its not ideal but If you keep the roots from freezing i dont think its a big deal and i could even spin it into a horticultural positive…increases Oxygen in a typical wet season
