Re-using kanuma
 

I have a bunch of what I'll just call "seasonal" orchids (i.e. bletillas) potted in kanuma.... Is it possible to sterilize and reuse the kanuma next year? I was thinking baking would be the best option for sterilizing...

Silly question... do they need repotting, since the medium doesn't break down? Or, if you do want to repoit to reposition the plant, you could dump the whole thing out onto a clean surface (like newspaper), reposition the plant, and put the medium back into the pot with the plant. You would certainly not want to use the medium on another plant (at least without sterilizing) but I can't see that there would be any harm using it on the same plant. I have done that with my Mediterranean-climate terrestrials (European and Australian) Tubers tend to head to the bottom of the pot so need repositioning, but still fit in the same pot. Medium is mostly inorganic, so nothing has broken down. I have plenty of newspaper, so can provide a fresh sheet for each plant with no big effort.

I was actually going to store them once they go completely dormant, they can't survive outdoors year round in my environment. The way they came to me they were kept cool and mostly dry (I actually kept them in my fridge for a few weeks before I potted them up). I have a mini fridge in the basement that I am going to keep at 40-45 throughout the winter and store my other non-orchid bulbs in as well and for that reason storing full pots may be difficult and unless I label and bag each potting media individually it would just be easier to sterilize it and start fresh next year

Good point!

what is kanuma?

Kanuma is a clay media, the stuff I have is smaller pieces (not sure if they make big ones). I've seen it used a lot with bonsai and some people are even using it for cymbidiums. I usually go for bark because of the environment I live in, but using it for these particular orchids I have absolutely loved it!

I found a great bulletin from the Houston Bonsai Society that gives good info about a lot of inorganic media components.

Inorganic-Components-Reference-Sheet.pdf

I reuse my hydroton (leca) and while I generally don’t reuse stuff from a sick plant if I want to clean it I fill a roasting pan with leca add a pint of water and cook it in the oven for a few hours at 300

I don’t know if that is hot enough to sterilize it but it makes me feel better

I reuse a lot of inorganic media like pumice, perlite and LECA. I leave it outside in the summer sun for a few months.

Sometimes it's so hot the LECA evaporates.*









*not really

Hehe, it doesn't get nearly hot enough for that here...... Fall is about to hit so hopefully we'll only be in the 70's for the next few weeks, but thanks!

LECA is fired at manufacturing to sinter the clay. The Japanese “soils” are merely baked to dry them and burn out organic matter, so don’t have the same degree of structural integrity.

If you want to be sure of destroying pathogens, and extended soak in a Physan Solution ought to do it.

What about LECA fried eggs? :biggrin: