Help! Persisting Mold in All repotted Phalaenopsis and Cattleya

[WaterWitchin]

Has anyone said anything about not watering? I thought my question was don't they drop leaves, and Roberta confirmed that and said don't fertilize.

This is confusing me. And it's my understanding nobiles do drop most or all leaves in winter... some of the more hybridized not so much.

[Roberta]

Of the Den nobile type, they tend to drop some leaves but not all. It does depend on the hybrid. Just to confuse the picture some more... I have a Den. that I got at a society auction about 4 years ago, that turned out to be mis-labeled. Based on the tag, I had been growing it in the GH... warm and humid. Didn't dry it out at all. Then, just a few weeks ago it bloomed... looked a lot like the species Den. nobile - not what it said it was. It was lush, never lost a leaf, grew like a weed, and bloomed about 6 months later than a Den. nobile "should" ... but I contacted the vendor who had donated it, and based on the picture, diagnosis was Den. nobile. The hybrids grown in Hawai'i are often in bloom at "unnatural" times.

So...in short, it is a continuum, not absolute, very dependent on conditions. If they get cold and dry, they lose more leaves. They survive and bloom just fine under a wide range of conditions. What I HAVE found is that following the "no water between Halloween and Valentine's Day" advice is a good way to kill them... I water them a lot less in winter, but not zero. In a dry climate (little or no morning dew during the "dry season") that's just too severe.

I do think that night temperature drop helps the blooming, with or without water reduction. I go back to what I have observed at Andy's Orchids... mostly mounted orchids so they dry out fast. But the deciduous ones (and some of the Den species go completely deciduous) get watered with the rest of the population (but do get a night temperature drop) and bloom very well. So... anybody who thinks they have the one and only formula doesn't know what they are talking about.

[estación seca]

Recall the Den nobile hybrids sold in flower have luxurious, full sets of spotless leaves on every cane. The growers water them all winter.

Growers manipulate temperatures to induce budding at any time desired. The commercial growing section of the Yamamato Dendrobiums Web page, now gone, explained this in detail. The Wayback Machine (archive.org) may have takenna snapshot.

[WaterWitchin]

I had never heard much about not watering in winter months. All I knew was when I first attempted growing a couple, they lost their leaves, I thought they were dead and pitched. And avoided dendrobium, period, for years.

I just looked upstairs and have two nobile dens. They get same treatment as everything else, and have bloomed for me. One loses most of its leaves every year, but keeps on chugging along. Somewhere along the line I just started growing dens again, but never paid attention to soft vs hard cane, etc.

My original main intent was to let a new grower not to be overly excited if his den started dropping leaves.

[nuriko1set]

Thank you for the more specific details! I will get a plant heating pad for when it gets a big colder and I guess wrap up a little tent for the Phal. Equestris to create more humidity. Its great to know that it likes 70%-80% humidity, it's a bit harder to create in my area, but at least that's a goal I should aim for.

I have another small orchid that I need to repot, it's a Phal. Dragon Tree Eagle AM/AOS. It's roots look ok so far, and has much more roots than the Equestris. It came in spike and started to form the bud here, but had a case of bud blast, and the little bud has dried up. I feel that I should repot it, since it's also in a squashed pot of moss and the moss look to be full of green algae. Now that I will not be using hydrogen peroxide to disinfect the roots, should I use Physan 20? Are there better products to use to clean roots before I repot into new mix? I am terrified of having pests or snails staying on the roots, so I've put it off until I have time to consult you awesome people! I've attached a photo of it and the roots. The first photo is the bud it started to develope, and the last one is the bud blasting.






Also, it is a dendrobium nobile, thank you Roberta for the advise on it. The grower I got it from said it is supposed to lose it's leaves in the fall, form the buds then bloom around early spring. She did mention that I should not water it until the canes look a bit shriveled. However I should've taken into consideration that she is from FL, where it's much more humid than my area. So I have noticed the aerial roots start to shrivel and dry. I have been watering it once every 3 weeks or so. I'll up the frequency to every week? I do spray the dried up roots with water a couple of times a week so they don't dry up completely.

OMG, I've finally finished writing this email, it's taken me 3 days ...

[Roberta]

I don't think that you need to do anything to disinfect the Phal roots... just get it out of that soggy mess and into something fresh. Don't worry about getting every last fragment of the old moss, won't hurt anything. Rinse well under the faucet, that will get it clean enough. I don't even usually cut roots - if the outer part (the velamin) is rotten and comes off easily, remove that. But the stringy core, if firmly attached to the plant, will help to anchor it in the new mix. I like bark because it stays airy - Phal roots, like most epiphytic orchids, really want "humid air" rather than "wet". Once it can (mostly) dry out between waterings, the algae/fungal stuff will be discouraged naturally.

If you use that you will need to water more often because it will dry out fast. Or fresh sphagnum if you need to water less. But when you water, let it run through the pot which pulls air into the root zone, then let it drain so that it doesn't sit in water.

[nuriko1set]

Just a quick update, I have been watering by showering the plants, and not soaking. The roots seem to be liking it so far. I do think they are drying a bit faster, which is great. I've started to mark down the dates that I water.

Also, I have another cattleya, which I had pretty much given up on. It had the same problem of mold. So I left it alone for a while, I checked up on it today and it seemed to be growing a new cane and new roots!!! So I gave it some water and set it under the grow light. Its been in quarantine, next to Northern window, which gets indirect but weak light throughout the day. Do you think to move it all of a sudden to a fairly strong grow light is too much? Should I move it incrementally, like 4 hours a day, then longer and longer?

Look at these little root nubbins, I can't believe this plant is so resilient, after all the challenges I gave it!

Thank you all for the methods, so far I feel fairly good. It hasn't been very long, but at least no failures so far!!

[estación seca]

I would movenit under the grow light now if it won't cook. What kind of light is it? How hot is the area under the grow light?

[JScott]

I personally love Physan. It's a great everything-cide, and it won't hurt your plants if you needlessly apply it. It may not work if the problem you are having is something the Physan can't treat, but dosing it with Physan won't do any harm. And I think it's just a good thing to keep on hand for when you need it. I'd dose your plants with Physan just because you can. It may help. It may not help.But it won't hurt anything.

[nuriko1set]

I'm glad to hear that about Physan! I wanted it to be on hand for when I repot, to use it.on the roots to disinfect and maybe get rid of unwanted pests, like snails. I know there are some roots that will need to be cut. I will try to keep as much as possible, but those that i cut need somewhat to be disinfected and cleaned right? I still feel uncomfortable leaving them.

Here is the light I have, it doesn't get too hot. I'm not sure about its specifics, not sure if this image will tell much. It was fairly chilly today so it was around 67 degrees under the light.