Help! Persisting Mold in All repotted Phalaenopsis and Cattleya

[WaterWitchin]

Here's the deal about growing orchids. It's sort of like raising children, training dogs, breaking horses. Everyone is going to give you a little bit different idea about the way to do it. And you can't do it all or your orchids won't thrive and your dog won't come when called. You have to look at your own environment, then figure out what works best for you within reason. There is no one size fits all.

After growing for awhile, you come to learn certain things that are fairly constant. These particular orchids like to be potted or mounted so their roots can breath or have air flow.

The Den and the Catt will be okay with 70F in the winter. I'm sure you will have a way in warmer months to bump up the temperature on the Catt.

The Phal equestris is a species, so will be less tolerant of not receiving what it requires. Growing at 70F is at the very low end of winter nighttime temperatures. Figure out how you're going to get it warmer. There are lots of ways to do that: seedling heat mat, coil up a small rope light and put under it boxed, etc. Ask if you need help with picking a way then choose one that works for you.

The equestris needs more humidity. It's a species, and is used to 70-80% humidity and higher temps. Get the humidifier and get it going. All three plants plus yourself will appreciate it. Or get a tall wide vase, throw a layer of that bark mix at bottom with water to top of mix, put the phal in there on top of something so it's not touching the mix and partially cover the top.

It appears you have three orchids, so taking each to the kitchen sink and letting water flow through shouldn't be much hassle. Watering through like that helps bring more airflow into the medium and down to the roots. Water like you mean it. Then feel the weight of the pot. When you lift it up, it's heavier. When it starts feeling lighter again, water again... that's one way.

The mix from Repot me is a good mix. Just pricey. I would soak it overnight prior to potting up your plants.

Get some Kelpmax, and use it once a month. Maybe for that Phal a couple of times in the first month.

Roberta, ES, anyone... is that a Den nobile? I only have one, so can't tell. If so, some words about Den nobile winter behavior/care would be helpful....

[Ray]

Seeing the phalaenopsis makes me think the mold you have been so frustrated with has been the result of the death and decomposition of the roots. There may be several things going on there, so let me describe some scenarios that might apply.

The “Number 1” thing orchid growers must learn is how to provide adequate water while maintaining adequate air flow to the roots. Unlike terrestrial plants that do their gas exchange through their leaves, epiphytic orchids have shifted much of that to their roots, an adaptation to conserve water.

The “watering and potting medium” connection relates to the size of the voids in the mix. When we water (drenching is better than soaking, in my opinion), most of the water pours right through. Some of it is immediately absorbed by the plant and the medium, but there is a third portion that’s critical - that held by surface tension in the void spaces. If those voids are small - too fine of a mix, or one that had gotten old and is decomposing and compressing - then water can fill them completely, cutting off air flow to the roots and suffocating them. (I am convinced that the myth that “orchids must dry out between waterings” is a misinterpretation of that. If you have a suffocating medium when watered, letting it dry out opens up the voids, letting the roots “breathe” again.). If the voids are large - usually from using a coarser mix - they cannot be blocked by water, so there is no problem.

Lastly is root system adaptation.

As roots grow, their entire cell morphology “tailors” itself to function optimally in that environment. Once they have grown, they cannot change. Move those roots to a different environment by repotting, and they are instantly sub-optimal and will start to fail. That’s why it is always best to repot a plant just as new roots are emerging; they will support the plant as the old roots fade away and decompose.

However, sometimes you just can’t wait, as the state of the current potting medium could threaten the life of the plant. In that case, go ahead and repot, then “baby” the plant until it recovers:

• Keep the plant very warm and shady. A heat mat under the pot can’t hurt.
• Invert a clear plastic bag over the plant and pot to trap the humidity. No roots means no water uptake, but the plant can still lose it through leaf transpiration.
• Keep the medium moist.

If you soak the plant in a KelpMax solution beforehand and water it with that solution, it’ll accelerate the process greatly, but it is not essential.

[Roberta]

That does look like a nobile-type Den. Temperature is no problem for that one. This type of Dendrobium does like to be drier (and cooler) in winter. My experience is that in a dry environment, you do still need to give it some water. And in that basket it will dry out fast. So that one, maybe water maybe once or twice a week. But still water thoroughly. We're fighting a fungal problem so keeping the root zone clean is very important - even if the water during (relative) dormancy keeps it from blooming, getting the environment cleaned up is #1, #2, and #3. It is a high-light plant (near a window would be good, will get both light and a bit of a chill)

So, that one can go dry between waterings in winter but still benefits from water after it does so.

[WaterWitchin]

Originally Posted by Roberta

That does look like a nobile-type Den. Temperature is no problem for that one. This type of Dendrobium does like to be drier (and cooler) in winter. My experience is that in a dry environment, you do still need to give it some water. And in that basket it will dry out fast. So that one, maybe water maybe once or twice a week. But still water thoroughly. We're fighting a fungal problem so keeping the root zone clean is very important - even if the water during (relative) dormancy keeps it from blooming, getting the environment cleaned up is #1, #2, and #3. It is a high-light plant (near a window would be good, will get both light and a bit of a chill)

So, that one can go dry between waterings in winter but still benefits from water after it does so.

And most leaves fall off, which is not of concern, correct? I remember when I first had one, all the leaves fell off and I thought it was a goner and trashed it.

[Roberta]

Originally Posted by WaterWitchin

And most leaves fall off, which is not of concern, correct?

Correct. And for those Dendrobiums, don't expect root growth until spring. And don't fertilize at all until spring when it shows signs of waking up. Basicallly, it should just sit there, probably until February-ish or thereabouts.

[SouthPark]

WW, Ray and Roberta pretty much mentioned all the execellent tips and points already.

Once a grower satisfies (pretty much permanently, and not just sometimes) conditions on a checklist, then the chance of issues like mold, fungus, mildrew, root drowning etc become small, or even eliminated. Naturally there are other things to watch out for too - such as insects/mites and maybe snails and things.

Somebody from another forum recently had a case of virus ----- but some things can be beyond our control, so just need to go with the flow, and still apply measures to minimise impacts from that sort of thing.

The orchid grower will usually need to assess their environment, and then see what they need to do to address holes and gaps that haven't been addressed. And of course, to have an understanding of the general growing requirements (temperature etc etc) of the orchids to be grown. Once done ----- it will be or can be smooth sailing for very very long periods of time. That's the goal ----- to achieve smooth sailing.

[estación seca]

Nobile types don't need to be dried out to the point of dropping all their leaves. If they get a cool winter and are watered they will flower.

[early]

As new grower after reading all the experts above, I look at my growing phalsc onc. and zygos. and realize even in dry new mexico, I am doing ok. I lost one phal early in the year, and one of my oncs, is not doing well, but does have some short new roots, but otherwise my 25+ all look healthy and happy. Have one short stem on a mini phal and getting all of them ready for winter. of my two seedling vandas, one is doing will, the other is surviving. My yearly vanda is doing well with root soaks 15 min once or twice a day, other wise in a vase. I appreciate all of you oldies but goodies, oldies in experience anyway, and Orchid Board has given me great advice always. ty ty ty

[SouthPark]

Originally Posted by early

Orchid Board has given me great advice always. ty ty ty

early - it's members like you that mention how you've been going, and finding the information useful toward successful long term orchid growing ----- that makes this forum really good, aside from the good personalities and also the general nice running of this forum.

That's pretty much it ------ the ability of us people to gather the information and techniques, then filter, pick/choose what information and method could work nicely for our growing area. Eventually, with enough time and experience and getting things together nicely ------ great results come, such as in your case.

The way I always see things is ----- if all those thousands or hundreds of thousands or million orchids in orchid nurseries all do really well ----- and are grown with automated systems, such as sprinklers etc, then we can know that they're doing the right things ----- and we just have to know more or less what they're getting right, and achieve good growing conditions all the time in our own growing areas.

On this forum, there are mix of growers - such as those that run/ran orchid nurseries, and those that have been involved with orchids really long times, and people that are starting up and reporting on what is working nicely for them. All the information from everybody contributing is very nice. There will be times when we encounter approaches or aspects that we hadn't yet seen of heard of, that may be helpful. This is the power in pooling and sharing information and knowledge. A nicely run forum like OrchidBoard is really good for this.

[Ray]

Originally Posted by estación seca

Nobile types don't need to be dried out to the point of dropping all their leaves. If they get a cool winter and are watered they will flower.

Correct. What the need is cool and NO FERTILIZER , not “no water”.