Dying paph

[spujr]

This plant is a goner but checking on diagnosis to avoid future casualties. The brown leaves are a little sticky to the touch,. Disease progression very fast. Warm temperatures (26-32C), I thought I had good air movement but wondering if it is enough? I do have to water overhead but I try to do it in the morning so leaves are dry before night.

Just trying to see what I can do to prevent future losses. It's a sanderianum so I am trying to keep good airmovement but prevent soul from dying out.

 

[big923cattleya]

That looks like one of the 'brown rots' to me. Those I believe are from it being too wet and too warm. It probably is not tied in to it being 80-90F if my math is correct. A day or two at the upper 80's is one thing, but day after day close to 90 degrees is another. The issue could be compounded by night time temperatures also being too warm. What are your night time lows like? 60-65 would be very nice in my experience but 78-80 coupled with 88-90 days may be the issue. Just too warm for days on end.
What is your definition of good air movement? To me good sir movement means a gentle swaying back and forth of the inflorescences throughout the entire collection. But if your air movement is closer to 3 mice blowing air across the plants, that is not nearly enough in my mind. My orchids outdoors seem to be always dealing with air movement of around 5 to 8 to even 12 to 15 miles per hour all day long. It does drop off at night but as soon as the sun comes up, the breezes pick up. Indoors over the winter, I have a 16" oscillating fan blowing on them 24/7. The plants located the farthest away from the fan are always gently swaying in a 3-5 mph breeze. Here is SE Michigan the air is seldom still.

 

[DirGo]

here is my experience with sanders

I see the bark looks very dark/wet, not sure even a bit white moldy spots? It could be staying wet too long. it looks to me that container has very little drainage openings for its volume - I would consider increase drainage at the bottom or even a few holes from the sides so it drains a bit faster.
it looks you have potted rather deep, I pot sanders a bit higher than other slippers to make sure the heart can always drain freely after watering. remember sanderianum is also one of those species in nature growing much more sideways so very free draining from the heart of the shoot. We artificially try to make it grow upwards, creating a bit of an artificial water recipient. I don't mind my sanders being a bit leaning to the sides, which seem to be their preferred growing anyway and creating a free draining flow.
They like minimum 18°C night temperature, they are very sensitive for colder & wet nights.

It is very difficult to give advice on a single plant picture. You need to consider all parameters: room/greenhouse area, water quality/frequency, air movement/temperature, light, fertilizer, pests...
Wishing you good luck and please keep trying sanders. I had lost one too before flowering them, it is still worth it!

 

[Ray]

Considering that all of my slippers stay constantly wet, I don't know that - by itself - is the sole issue.

It does appear to be potted too deeply, though. In my experience, I try to avoid the medium making contact with the base of the leaves.

 

[spujr]

Thanks for all your feedback.

The pot is a rand aircone pot so the center is elevated to provide good drainage near the crown.

I noted the depth, and will watch out to avoid planting too deep in the future. This particular death was quite discouraging because when I got it there was no roots but it grew several nice roots before perishing.

I wondered if my night temps weren't going low enough. During the summer I can barely get it to 25C.

As for air movement, I have 1 small fan facing horizontal to the plants slightly above the foliage. This means some of the leaf tips move slightly but no plant is directly in front of the fan. Below is a picture from my timelapse camera that you can barely see the fan on the left (the dead plant was in the back left side). This shelf is in a tent with 3 other fans moving the air around. I'm pretty sure if I lite a match, the smoke would quickly dissipate in all locations.

RH stays above 85%.

Ps, if the leaves in the photo below appear very light green, it's the same color when I got them, most were rootless but are beginning to darken slowly.

 

[big923cattleya]

Too much humidity, too warm at night and not enough air movement.
It is just my opinion. 25C is 77F right? I grow mine inside at 63-66F over the winter. My summer nights outdoors have a much broader range , 55-70. Daytime highs are 75-85 outdoors. Winter under lights my days run 70-75.

Why were so many plants rootless when you got them?
You could have light green leaves because of too much light. How many hours are they on?

 

[spujr]

Too much humidity, too warm at night and not enough air movement.
It is just my opinion. 25C is 77F right? I grow mine inside at 63-66F over the winter. My summer nights outdoors have a much broader range , 55-70. Daytime highs are 75-85 outdoors. Winter under lights my days run 70-75.

Why were so many plants rootless when you got them?
You could have light green leaves because of too much light. How many hours are they on?

I got them for a good price from the orchid inn, they were in a bad part of the greenhouse and probably went too long before repotting. I checked my light levels using a good quality PPFD reader, can't recall the exact number in memory but believe it was in the 40-50ųmol range, 12 hr light duration. Again, would need to double check the number but I remember it being on the low-med range.

I'll decrease the humidity a little and try to bring down the night temps a little more. I read sands are thermophyles and like (at least daytime) temps of 27-29C.

I'll also see about getting another fan just for insurance.

 

[kc6847]

I think it may have to do with them not having an established root system/genetics too. I've noticed that almost every plant from OI origin recently have had little to very freshly repotted roots despite the broken down media. Also, Sam said that the last P. sanderianums he sold are now within several generations of breeding and I notice a big difference between the world 101 x red delight vs the cross "from over 20 years ago" that got redone by Hilo orchid farm. Also, the unestablished paphs have all managed to establish themselves besides the sanderianum, and with the status of the species right now, I'm suspicious of inbreeding depression.

All to say it might honestly not be entirely your fault.

 

[big923cattleya]

Personally, I would keep it in mind that these sanderianums that you are dealing with are seedlings, babies. To expose them to the extra warmth that you think that they need may in fact be just too warm. An adult plant mat tolerate this temperature range, but babies? I am not so sure about that.
And I do not think that that little fan you are using is insufficient. Air blows from the fan and flows gently towards the opposite end. That fan does not seem strong enough to then circulate air, 180 degrees and have it turn around and provide air movement to those plants nearest the fan, left and right.

As I said, with my indoor setup, I have 2, 16" oscillating fans bowing on to my three plant carts from 8 to 12 feet away. The fan heads go back and forth, gently moving the air around. When I water early in the morning around 9am, most leaves and things are dry by mid afternoon. Small pots are pretty dry by the next day. I am watering small pots like yours every third day. My plants are in a warm buoyant atmosphere. Yours could be living a sauna bath. Air movement could make a huge difference. 90 degrees, 85% humidity and 77-80 at night might just be too much.