Thoughts on re-using bark and sphagnum ?

[orchidsarefun]

Has anyone tried to re-use bark and sphagnum ?
Some orchids ( like catasetums ) are potted up annually. I spread any "old" bark and moss that I have after repotting, on the garden as a top-dressing, but wondered if I washed it/left it in the rain to leach out salts etc, if it would be good for re-use ? Especially with longer-lasting bark like orchiata ? I have noticed too that a lot of the regular bark from last year that I spread on my veggie beds still looks OK.....
I might try it this year, wouldn't do it more than 2x but in theory you should be able to do so until you see visible deterioration in the bark. If sphagnum can spend years in the "wild", then surely the same principle would apply ?

[Ray]

Keep up with the "garden addition" mode. An extended exposure to rain and sun will not sufficiently remove absorbed minerals and plant wastes, will harbor even more pathogens than they had previously, including new ones your orchids have not seen, but worst off all, the exposure will hasten its decomposition, meaning that it will become a root-suffocating sludge much sooner in that second cycle.

[MattWoelfsen]

This is a concern I have about re-using potting material. When I repot, I place the old media in my garden, like you have done for your old media. I did think that I could re-use old media in my new pot, after I washed it out--like I do with pots. But then I got to thinking, how much time do I want to spend washing and leaching the old stuff? Would I be 100% confident that I've eliminated chemical residue, pests, and other maladies that I might transfer to the new plant?

My conclusion: not worth my time and certainly not worth the effort I would go through trying to eradicate any pests that my new plant would experience as a result of re-using old potting media. I spend too much money on orchids to take that kind of risk. Ironically, my garden plants seem to be doing okay with the old stuff.

[Brooke]

Reusing old media would be a great way to spread a virus. Would it be worth it if you contaminated another plant?

Sphag in the wild is growing and not dehydrated.

Brooke

[quiltergal]

Why bother repotting at all?

[AnonYMouse]

S'why I use as much straight inorganic material (LECA, lava rocks) as I can

[BettyE]

Originally Posted by AnonYMouse

S'why I use as much straight inorganic material (LECA, lava rocks) as I can

I do exactly the same thing! I would NEVER even think of re-using bark or moss...too much risk of spreading something bad...BettyE

---------- Post added at 09:32 AM ---------- Previous post was at 09:26 AM ----------

Originally Posted by Fairorchids

I do not think that is hot enough to kill virus. I believe that you need to go 400-450 deg F for that.

I agree with the above statement...I heat up the bar-b-que, and let the well rinsed LECA roast for about four hrs. at about 450 degrees. No problems, so far...BettyE

[galgoa]

What is your opinion about sterilizing with microwave oven?

[Orchid Whisperer]

Originally Posted by galgoa

What is your opinion about sterilizing with microwave oven?

If you are 100% certain that a material has never contacted plant material that could transmit a virus, you could try a microwave to deal with some bacteria and fungi only. Some fungi and bacteria may not be killed by microwave temperatures. I can really see this as an option for only non-porous, non-metal tools that will not melt (and there are few of those that I use with orchids). Growing medium would probably dry out and catch fire before it stayed at high enough temperature to be sterile.

For viruses, you need to keep what you are sterilizing at high temperature (I have heard 300F) for an extended time to achieve sterilization.

You can use bleach to sterilize non-porous tools. Sodium hypochlorite in bleach is a powerful oxidizing agent, and oxidizes organic material that it reacts with, presumably including fungal and bacterial cells an viruses. It will not fully penetrate into porous growing medium, or fully leach back out, so I would avoid using bleach to sterilize organic growing media.

[katrina]

Why do you think you need to repot your Ctsm every year? Or any orchid for that matter?

Ctsm (like most orchids) will do better if you pot them in a pot large enough to accommodate 2-3yrs worth of growth and then just let them grow on until the medium is questionable or until they could use a larger pot.