Green/white mold on phalaenopsis roots

[estación seca]

Give yourself 1 repot per plant per year. No more. You've used it up on this plant.

Mold like that grows on dead tissue. It won't hurt living tissue. Just ignore it.

You might need to wait over a month to see new root growth.

Phals carry leaves in proportion to their water balance. Healthy plants with a good root system typically carry 3-6 leaves on a windowsill, and 6-10 in a warm, humid space. If anything disrupts water balance they drop leaves. Bringing a greenhouse plant into a home, cutting off roots or having roots die often results in leaf drop.

Various people here have mentioned Phals make 1-3 leaves per year in their homes.

[Shadeflower]

Originally Posted by WaterWitchin

ShadeFlower likely missed the part about your RH being 30-45%.

mold doesn't grow in 30-40%. People say stuff online all the time. I don't want to nit pick but mold does not grow in 30-40% so I am sure with a calibrated hygrometer the humidity is rising over 60% every night otherwise mold would not be growing. I haven't got any mold and the only time I get mold is when I get it in substrate from a new purchase, ie I bring it into my home.
It can then be eliminated easily by keeping a home at 30-40% for 2 weeks. The substrate needs to be let to dry thoroughly too.

One of the best fixes for mold is to keep a plant bareroot for 2 weeks in a vase and spray the roots a little bit daily , that way they stay hydrated and dry out enough for mold to have a tough time growing.

How long it should take to see improvements? Months. The aim is to watch out nothing declines.

From experience you lean what plants respond well to and what they don't, you then apply that to future plants, everyone loses orchids along the way learning what they like or dislike but it is very hard to see instant results. you need to look back and see what has worked well for you in the past and provide that again in future.

[Phalaenoptics]

Thank you both for your wisdom and input!

@Estacion I like this rule of giving myself 1 repot per year per plant - since so much of the advice out there is too "unpot, look at the roots etc" it's tempting to do it... all the time, whenever there's a sign of decline. I just haven't had them long enough to know what's normal (even if it doesn't look perfect).

Originally Posted by Shadeflower

One of the best fixes for mold is to keep a plant bareroot for 2 weeks in a vase and spray the roots a little bit daily , that way they stay hydrated and dry out enough for mold to have a tough time growing.

How long it should take to see improvements? Months. The aim is to watch out nothing declines.

From experience you learn what plants respond well to and what they don't, you then apply that to future plants, everyone loses orchids along the way learning what they like or dislike but it is very hard to see instant results. you need to look back and see what has worked well for you in the past and provide that again in future.

@Shadeflower - I've never heard of this bare-root vase method before and I really like it! I think I will definitely have to consider trying this next time I have an orchid with issues. I suppose it could help struggling orchids as well with root rot issues?

I think my problem (and a common newbie problem from reading posts on this board) has been to overcorrect when I see declines. That dangerous stage when you know more than someone who knows nothing, but you lack all sorts of practical experience. It's like that saying goes, "a little knowledge is a dangerous thing!"

I really like your advice about experience and that it's okay to lose some plants along the way. It's very reassuring. I am going to keep that in mind going forward!

[mvmgems]

Originally Posted by Shadeflower

mold doesn't grow in 30-40%. People say stuff online all the time. I don't want to nit pick but mold does not grow in 30-40% so I am sure with a calibrated hygrometer the humidity is rising over 60% every night otherwise mold would not be growing. I haven't got any mold and the only time I get mold is when I get it in substrate from a new purchase, ie I bring it into my home.
It can then be eliminated easily by keeping a home at 30-40% for 2 weeks. The substrate needs to be let to dry thoroughly too.

One of the best fixes for mold is to keep a plant bareroot for 2 weeks in a vase and spray the roots a little bit daily , that way they stay hydrated and dry out enough for mold to have a tough time growing.

How long it should take to see improvements? Months. The aim is to watch out nothing declines.

This is not the case. I have four independent hygrometers from two different brands, and they consistently match. One of them has max/min recording features, and the absolute max that ambient humidity gets when temps drop to ~65F at night is mid 50s.

I do have most of my orchids in cache pots and it appears that the humidity in the pot is high enough to promote mold growth. I've since removed that particular plant from the cache pot, and healthy plants with mold growing on the bamboo skewers or bottom bark I've left alone.

We also get bread and pastries molding over very quickly when left in the pantry cupboards instead of the refrigerator. I reside in east San Jose on a sunny hillside. It's definitely warm and dry.

[WaterWitchin]

Originally Posted by Shadeflower

mold doesn't grow in 30-40%. People say stuff online all the time. ...

As mvmgems points out, not true. People DO say stuff online all the time, accurate.

Totally missed my point ShadeFlower. You told the OP to get a dehumidifier. My point was with 30-45% humidity as the OP indicated was their norm, it wasn't necessary.

[katsucats]

Don't quote me on it, but I've seen a little bit of hairy white mold here and there and I don't consider it a problem unless it is accompanied with massive die back of roots. If there are still good roots, then we're okay. The mold might be an indication of a moist medium or lack of air circulation. Air circulation is good, but if I'm growing indoors in a dry climate, I need to compensate by keeping the medium moist. I don't think the mold itself is harmful to the plant, although it might be unsightly. On the other hand, if I see black water-soaked roots, it's time to take action.

Digging the plant out of the medium once in a while isn't necessarily a bad thing, but it shouldn't be taken lightly. Plants require an adjustment period when it changes media, and overreaction too often would kill it. If you're the type to freak out over little problems in the medium, then provided you have a way to keep the humidity up, growing mounted, bare root, or semi water culture are probably the only to go.

I have a couple plants hanging over my shower. Or you could simulate an open terrarium with a vase. However, the downsides to vase culture in my opinion are the expense of a suitable vase, the watering maintenance due to the weight of the vase and lack of medium.

Note though that just because the visible portions of mold are inactive in the two weeks that you throw it in a vase doesn't mean it's permanently gone. I would think it is inadvisable to pull plants out for 2 weeks unless there is a serious concern like fast spreading rot that requires drastic action.

[Phalaenoptics]

Thank you for your post, Katsucats! I really appreciate it. I'm learning to be okay with a little bit of fuzzy white mold here and there, especially when it would be more of an issue to unpot and repot! It's definitely part of my growing pains as a new plant parent, figuring out the nuances of orchid care. Overall, my orchids are doing great, but I lack the experience of time and knowing when to chill.

I suspect the one orchid I killed was a result of my newbie mistakes and overcorrecting. At that point, I'd had several successes, so I was overconfident in thinking that I had this whole orchid thing down. So in my enthusiasm, I watered a "just add ice" phal before repotting, not thinking about the nursery plug that I knew was inside. My well-meaning partner placed it into a bathroom with poor ventilation, in order to quarantine it since I spotted an unidentified buggy crawling on its bark. The next day, when I unpotted it, the roots were soggy, although most were still firm to the touch. Following a MissOrchidGirl video, I trimmed away the completely sad parts, sprayed everything with hydrogen peroxide, and generously sprinkled with cinnamon. I let it dry for a few hours, then potted it up again in new mix. Within a few days, green and white mold was growing all over the roots, even the green parts. The rest of this story is a sad tale of unpotting and continuous overcorrecting as the mold returned again and again until I had a sad, rootless phal.

In the postmortem I can say that I probably could have just let it dry out after the first overwatering and let it recover before potting it up again. I also think the hydrogen peroxide and cinnamon probably damaged living tissue, which was what allowed the mold to grow.

But for the purposes of learning, what would have you guys done in this case study?

[WaterWitchin]

Watering a "just add ice" phal and leaving it overnight in a bathroom was not the problem. It probably already had some crappy roots going on in that pot. And depending on the "buggy" you saw, could have already had some rot going on.

If I get a grocery store phal, they're usually packed tight with sphag. I soak it for about 10 minutes, take out all the old sphag and anything else. If it has any black mushy roots I see if the outer velamen can be easily stripped off, and do so, leaving behind that wiry inner root. Then soak in Kelpmax for awhile, then repot with your medium of choice.

I've never gotten mold on orchids or the medium. Even back when I grew in a bark mix. Not sure why you're getting mold developing so quickly, unless it was already present. Again, see mold, use a fungicide. Lots of repotting doesn't get one anywhere and annoys the plant.

Peroxide can destroy the velamen. Cinnamon is a fungicide by way of being a desiccant. Not really for use on roots. It has it's place in the toolbox to dab on the end of a leaf cut, etc, but not for roots. That was likely the kiss of death for the phal to begin with.

Much better to learn with a just add ice phal, than an expensive hard-to-find orchid. I understand exquisitely thinking you have a few sucessful plants, then deciding you got 'er all knowed up. Have worn that holey Tshirt many a time.

[Dusty Ol' Man]

Reading through this thread I see one point that, while touched on briefly, should be considered more: air movement. If the affected plant(s) is in the house, air movement can help prevent, or at least limit, mold growth. It doesn't take much. A ceiling fan on low (or the equivalent) would be fine. As long as the air is moving, molds and mildews have a hard time staying humid enough to grow.

[katsucats]

You called it over watering because there's a nursery plug and it had soggy but firm roots. But I don't think you over watered at all. Firm roots are healthy roots, and of course they'd be moist after watering.

A lot of people freak out over rockwool plugs or packed moss, but the orchid survived in that medium for at least a year or two before it landed on the store shelf for you to buy. There isn't a huge difference between the greenhouse tray and the spot by your window or table. So why is the rockwool that kept the plant alive all this time suddenly a bad thing after taking it home? It's really not. Rockwool is an inert medium meant to retain dampness but drain excess water. Commercial operations water exactly as you would, by dunking the plant in water (individually) or watering until the medium is saturated.

What I would have done after your partner placed it in the bathroom is simply to put it in a place with indirect light until the medium becomes slightly damp to touch and water again.

I've never heard of hydrogen peroxide killing any plants, especially when some people use it routinely. A quick Google search turned up a bunch of people repeating the same mantra, but no specific examples or scientific evidence. Cinnamon has weak fungicidal properties and is a desiccant that absorbs water and dries things out. It's not good for roots, but sprinkling some is not going to kill the whole thing.

As a side note, I try to remove as much of the old medium as I can when I repot to my preferred medium (LECA) nowadays, but I still have a Dendrobium that I've bought and sometimes neglected since nearly a decade ago. It's partially died and revived a number of times before I decided to get back into orchids again, so unfortunately it's not a stately specimen. But it also isn't dead. Back then, I took the plant, the plug and some of the remaining bark/moss and dropped it directly into LECA for semi-hydro.

These plants don't die that easily. Besides disease, improper water schedule or technique kills orchids, and all the repotting and root cutting probably exacerbates that. If the advice is to not water the orchid for a few days after repotting or sprinkling the cinnamon, then that makes it even worse.