Thoughts on re-using bark and sphagnum ?
 

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 ?

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.

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.

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

Why bother repotting at all?

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

What is your opinion about sterilizing with microwave oven?

Some orchids I have are overwintered bare root....

Surely a bleach wash will kill any viruses in the bark ? Works for pots. I think I may just experiment if the bark seems as good as new. I have had people tell me that some orchids they have haven't been repotted in years, me using bark 1x, after due disinfecting is not going to be the end of the world.

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when you only have a few plants, repotting every year is fine, but when you have a greenhouse full, you repot some everyday and STILL never catch up, lol....a lot of my greenhouse plants go a couple years in the same media...I tried to be more regular with the ones in fine media like paphs...but cattleyas usually go 2 years for me....only buy really good hard fir bark and you will be fine.....leftovers after repotting ONLY go in the garden....I do not recommend trying to reuse it!

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.

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.

Steve Male, the owner of Fishing Creek Orchids in Harrisburg PA, is one of the best growers I have ever met. He repots EVERYTHING, including his catasetums, annually, without fail.

Keeping a good, healthy root system is the key to successful growing. Over time, media decompose and/or build up minerals and waste products, making the environment less perfect.

Certainly, there are things you can do to extend the period between repotting sessions - use pure water, light fertilizer loading, water frequently and thoroughly, and use media components that don't decompose so rapidly - but if you think for a moment that your plants are immune to the degradation of the root zone environment, think again.

Over-watering and/or over fertilizing are death sentences in their own rights. If you do either (worse yet, both) your plant likely won't be around a year to bother w/repotting.

On the other hand, if those two things are not an issue AND if one is using a good quality bark then a plant will not only do OK for 2 or 3 years...they can and do thrive.

I don't use bark a lot but what I do use is orchiata and it would be utterly ridiculous to think that stuff needs to be replaced yearly. Hell, it takes nearly a year before water isn't just rolling off it as if it were rock rather than bark.

I've heard good things about Fishing Creek. I don't know why he switches everything out each year...wouldn't even begin to understand or know why he chooses to do that...but, I'm sure he has his reasons. Maybe he uses a lesser grade of medium? I don't know. Regardless, I don't think repotting annually is necessary on most orchids. Paphs and/or anything in sphag only...could/might be the exception here. Maybe? I understand that paphs do quite well (maybe even best) when repotted annually. However, most other orchids are going to do better w/less root disturbance. Some, in fact, will sulk for a couple of years after a repot. Even w/out the sulking...it isn't necessary to repot every year. A good quality medium is not going to break down in a year...unless something exceptional is going on. Miami + lots of rain could be included in that exceptional type thing but someone growing in our area of the country doesn't experience what someone in Miami would. All of this is moot anyway because the OP is talking about reusing old medium to do the repotting. If that's the case...it's absolutely a better option to simply leave the plant in the pot and wait a couple of years rather than potting it up in medium that was used previously on other plants.

Mine goes to the compost heap/ garden. I might feel differently if I used Orchiata. I feel that the plant will be in it for one to two years. I also have many plants in lava and they are doing well.
I thought it was 2 to 3 years too. Get a bigger pot?

I've met with Tim Maye, the US distributor for Orchiata. He claims that this product lasts 8 years. Based on that fact, you may wish to re-think the annual repotting.

I too am stingy with the orchiata. I just collect it up, and when I have enough, I put it in a large baking pan, and let it go in the oven for 2 to 3 hours at about 200 degrees. Any bugs left after that, are more than welcome to my orchids.

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

My question is why do you repot every year? Unless the orchid is actually out growing it's pot, I would just leave it. Most media should be good for a few years. With bark like orchiata it should last 3 or 4 years. I have cats in orchiata that have gone 5 years. I use the 1/2 inch medium size bark. I also have charcoal and sponge rock in the mix.

The are a few orchids that fall in this category of potting every year. Pleione is one and many do Catasetums so I understand what the OP's dilemma is, do you reuse orchiata or not? Do you reuse one year old bark? This is kind of where the longivety of orchiata which they quote as an advantage kind of fails for me, build up of nasties, mineral build up etc and the gradual reduction of the very benefits orchiata have surely reduce with age. 2-3 years at the most and I would want to repot with fresh. If orchiata is as good as stated on the breakdown front then you should be able to sterilize and freshen it up by adding lime. But what about mineral, pest, fungal and bacterial build up, is orchiata immune to that?

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I don't reuse media. I have invested quite a bit of time and money in my collection, I won't take the risk of spreading disease, pest or virus. In fact, any plant that looks questionable is removed from the greenhouse until it is cleared of possible issue. If it's not cleared, it's destroyed.
I won't risk the entire collection to save a couple of bucks or keep a bad plant. It's just not worth it.

I don't necessarily repot every orchid every year, but I will repot if the material does show decomposition.

If the potting media is mostly inorganic materials, then I only change out the organic constituents and save the inorganic stuff if I feel they're still usable. Usually if this is the case, repotting these orchids are very infrequent.

If they are in highly organic potting media that stay moist or wet a large proportion of the time, then these are the ones that get the potting media changed out as soon as the first signs of decomposition occur.

Dracula spp. are notorious for going downhill quick if they are not repotted into fresh moss often. Many Masdevallias, certain Stelis, certain Platystele, many in the Pleurothallis complex, and many other Pleurothallids that can be grown in traditional pots or net pots are the same way. I'd probably say these orchids would need the moss changed out every 8 months to 1 year, however soon the moss starts to look grungy.

I wouldn't really reuse organic potting materials because if it was showing signs of decomposition, then it could rapidly start breaking down when reused; but if it was inorganic and cleaned before use, then I'd feel safer doing it.

If throwing the old organic potting material seems like a waste, then composting could be the way to go, or just continue to dump the organic stuff under the trees or in the flower beds of your yard.

---------- Post added at 11:53 PM ---------- Previous post was at 11:39 PM ----------

Btw, I don't grow a whole lot of Catasetinae, and of those I do grow, I haven't had them for a long time, so I wouldn't be able to say whether they need to be repotted every year or not with great confidence, but so far, I haven't seen the need to.

I've also had the experience of having failed to have a Catasetum thrive if they were grown in a pot that was far too large and if they were grown in moss.

So far, I've found growing a Catasetum in a pot that was just large enough to fit the roots in should be good enough to accommodate just enough subsequent growths for at least 1 growing season.

This thread illustrates why I am not a fan of orchiata.

Most orchids outgrow their pot in 2-3 years.
Terry Root repotted his stud plants (Paphs) annually.

Even if the material lasts 8-10 years, what's the point?

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 ----------

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

I just throw the old pot in with the new stuff (assuming the media is still good), so media that lasts 8-10 years works great for me.