Paph. sanderianum

[katzenhai2]

This Paph. sanderianum is a left over from a culture of seedlings from 14 years ago. Short windowsill culture, then off to the terrarium. After 2 years it was transferred to the culture of another person who had practically not looked after it over the years. Two years ago I took it over again and it still looked like a seedling.

It has developed quite well since then, the leaves are very firm, they are green and the root system is great. When I took it over it had the same problems as now. I then transplanted it into washed and sterilized Coconut husk chips (CHC) and poured teaspoonfuls of lime powder onto the substrate. Fertilized with Schwerter orchid fertilizer (5ml/L). It recovered quite quickly.

Unfortunately I made a mistake a few weeks ago and accidentally added some really really old Superthrive from the fridge to the water. Exactly 2 days later the drama began: Sunken spots developed on the leaves. When I added pure osmosis water to the pot a few days later the symptoms worsened the next day. The lowest leaf was already old and yellowish and had the most sunken areas. After the osmosis water treatment it was completely infested a day later and was muddy brown. I removed it immediately. My theory on this: Unwanted bacteria have developed in the substrate and on the roots, now also inside the plant, and the osmotic pressure sucked them into the plant.

My first treatment was to replant in new substrate (again CHC, this time with perlite and activated carbon) and watered with calcium nitrate and lime powder, also with orchid fertilizer a day later.

What else can I do? The spots seem to be multiplying very slowly. Biting insects can be ruled out, I can't see anything with a 15x magnifying glass. It seems to be inside of the plant itself.

Culture:
It has been in a terrarium full of living Sphagnum for 2 years. It is permanently wet which doesn't seem to cause any problems with the roots. Temp. is 23°C (73°F), rH 70%. The terrarium (60cm x 30cm x 30cm) never had a fan before. It is closed with glass as a lid but there is a gap of 10 cm wide. I use a LED with 4500K which gives 3000-5000 Lux. For the last 20 days I have installed a 300rpm fan as a test, just to see what it does. I didn't really think it was necessary. My fear was that it would also suck in pathogens from outside the terrarium and spread them inside. I have now switched off the fan again, perhaps it is causing a draught on the sanderianum and it is therefore not recovering well.

P.S.: I once rubbed the spots with charcoal powder and later removed it. This is why some areas may appear slightly black at the edges.

 

[Justin]

I can't imagine the superthrive was the root cause.

Did you remove salts from the CHC before use? CHC has kind of fallen out of favor with many Paph growers.

With the lime ammendment is the pH of your runoff water too high? What are you feeding and at what rate?

The sunken leaf cells do not look too alarming. I am sure the plant will grow out of it.

 

[katzenhai2]

I can't imagine the superthrive was the root cause.

Did you remove salts from the CHC before use? CHC has kind of fallen out of favor with many Paph growers.

With the lime ammendment is the pH of your runoff water too high? What are you feeding and at what rate?

It started immediately after this one watering.

The question is not clear exactly how much nitrogen the fertilizer contains (14-8-7), according to the calculation it would be 1400 ppm N, but according to the EC (560 µS) that can't be right. I also assume 140 ppm, especially as I have been watering the plants with it for 2 years and they don't look like they are getting too much of it. BTW, the manufacturer (Schwerter Orchideenzucht) has not responded to my question regarding the contents. It contains N as nitrate and ammonium as well as P and K and micronutrients.

The pH I measured was 5.2 with the addition of Superthrive (maybe this low pH was the main cause?) - without its pH 6.3. I add the lime powder (Calcium carbonate) to the substrate later and wash it in. From experience I know that the sanderianum reacts always good to lime powder. It's like a cure in some situations. Some users speculate then that the pH of the substrate is too low - but according to the measurement this is not true. I've read there are also bacteria in the lime powder (Calcium carbonate) and perhaps they act like a probiotic? Idk. Only the P. sanderianum reacted like this, all the other Paphs (P. amabile, P. lowii, P. Carol, P. Deperle) didn't seem to have a problem with this irrigation.

This was also the first time I had used this fertilizer combination. Normally I do it differently and irrigate 3 times a week every two weeks: Fertilizer, on another day calcium nitrate and at last magnesium sulphate. I had bought the Superthrive new and wanted to use it for the first time but I grabbed the old bottle. Likewise the urea: I had read that paphs could benefit from it. Perhaps I should have administered these things separately and not together...

The sunken leaf cells do not look too alarming. I am sure the plant will grow out of it.

Thank you very much. I am relieved to hear that. I am very attached to this plant, it is something personal to me.

 

[Justin]

Others can provide some feedback but I would just go back to your normal culture and not worry.

 

[Ricardo Boricua]

Watching this post. My experience with sanderianum has been too dreadful to speak of. Very odd since most other Paphs related to it do well in my conditions with routine care.

 

[katzenhai2]

Watching this post. My experience with sanderianum has been too dreadful to speak of. Very odd since most other Paphs related to it do well in my conditions with routine care.

I understand that very well. I have mine quite stable, except for these little "gimmicks" that it does when something doesn't work as standard. All the other Paphs are unimpressed but the sanderianum is guaranteed to b*tch around.

 

[richgarrison]

I understand that very well. I have mine quite stable, except for these little "gimmicks" that it does when something doesn't work as standard. All the other Paphs are unimpressed but the sanderianum is guaranteed to b*tch around.

If someone in our society came in with the plant pictured, I’d have diagnosed it with pseudomonas. If they then told me they had been growing it in a terrarium (high humidity, few fresh air changes) I’d be more convinced of that diagnosis. Lookup Sue Bottoms orchid disease writeups on the saint augustine orchid society web site. You’ll see some pictures that match your leaf above. She gives remedial advice as well. I think your treatment with superthrive is coincidental with the arrival of the leaf symptoms.

 

[katzenhai2]

If someone in our society came in with the plant pictured, I’d have diagnosed it with pseudomonas. If they then told me they had been growing it in a terrarium (high humidity, few fresh air changes) I’d be more convinced of that diagnosis. Lookup Sue Bottoms orchid disease writeups on the saint augustine orchid society web site. You’ll see some pictures that match your leaf above. She gives remedial advice as well. I think your treatment with superthrive is coincidental with the arrival of the leaf symptoms.

Thanks for the tip. I'll have a look.

However, a fan was running in the terrarium at the time and the leaves are never wet in that location. But I also sprayed it with the fertilizer solution and waited in the living room at 40% rH until the leaves were dry.

 

[richgarrison]

Thanks for the tip. I'll have a look.

However, a fan was running in the terrarium at the time and the leaves are never wet in that location. But I also sprayed it with the fertilizer solution and waited in the living room at 40% rH until the leaves were dry.

Understood. Relative to the fan, was the terrarium open to allow for fresh air exchange?

 

[katzenhai2]

Thats the setup. Wadding is fitted above on the right as there is a gap because of the power cable for the fan. So air gets through. The top left is open. I assume in this small setup and at 300rpm there is still enough air being sucked in from the outside. Mathematically the fan would have a circulation rate of >200x per hour in this small place even at its lowest setting. However it only feels like a fine breeze. Just wanted to get some moving air even though there were no problems with the setup before.


In this context I wonder whether the plant close to the fan might be getting too much draught? P. sanderianum is on the left side. The plants in the row with the fan between the P. sanderianum are new arrivals and were not present when the problems occurred.

 

[richgarrison]

Thats the setup…….

Cute setup…. I’d certainly be guessing at any suggestions for change. Just be wary of too much humidity. That can be a contributing source of infection, if in fact that is what we’re seeing.

 

[katzenhai2]

Cute setup…. I’d certainly be guessing at any suggestions for change. Just be wary of too much humidity. That can be a contributing source of infection, if in fact that is what we’re seeing.

My experience with this setup goes back up to 10 years. Problems with too much humidity only occurred when the lid was completely closed and the humidity was 100% - but then the roots just shot out of the plants. I've already tried a few things. Otherwise the Sphagnum does its job very well. For example, I have never had any problems with Erwinia.

In this respect I am quite confident about the setup. First and foremost I was concerned with immediate relief measures for this plant. I appreciate your advice though, no disrespect intended. I don't want to come across as resistant to advice. I am therefore reluctant to show the setup as I already know the reactions to it.

I know it's difficult to communicate what I've experienced with this setup so far. I know the criticisms of it and they all go in your direction. But I can't confirm them from experience. I know that I did something wrong with the P. sanderianum, though the main cause is not yet known (low pH of fertilizer solution? Bacteria infected Superthrive? Or both?), and of course the setup is part of it - but not the main cause. It's like someone using rock wool: One person's setup works great, another person's roots rot. You say: "a contributing source", I agree with that! But not much more, and I can say that with a clear conscience. Though I understand its difficult to make remote diagnoses. And such a setup is really not the norm.

Physan is no longer available in Germany - it has either not caught on or is no longer approved.

 

[richgarrison]

My experience with this setup goes back up to ….

Understood to all of that. And no offense taken.. much of this back and forth goes to. ‘What works for you…. Works for you!’ You have a system there. And you have the best view and knowledge of that. The best we can do in conversation is point at our observations and knowledge base.

Good luck. You are certainly on a ‘journey’ with that plant!

 

[BrucherT]

The only thing I’m doing anymore is Ray’s potions. His beneficial bacteria mix is the bomb.

 

[katzenhai2]

The only thing I’m doing anymore is Ray’s potions. His beneficial bacteria mix is the bomb.

You have so many products in the USA. Many are not available here on our market. There don't seem to be any probiotics for plants here.What is available are fertilizers with extra vitamins or amino acids. But that's probably not the same.