Medium problem killing Phals; B4 I repot knowing cause will help - Orchid Board

Skippersmom · #1 03-10-2021, 11:11 PM

Greetings all wise and all knowing 'orchidistas'!
I live in Nebraska, so 'All My Children' are living indoors, sitting on humidity trays and with occasional warm mist humidity. Watered weekly with about 20 minute dunks in the sink with 3 of their closest friends. Alternate fertilizer, kelp or probiotic.

So,... meet the 4 members of the Aquatics 101 program. Fresh out of their pots as of last night. 'Look Ma! No roots!" [insert favorite explicative].

Back story - they are part of a group of about 11 Phals I rescued from my Dad's place after he went to long term care. They were in various states of too dry, too wet, never been repotted, etc. Some with poor roots. They all got repotted. Some right away. Some I cleaned up the bottoms, put in water [cuz I didn't know better]. Most of them sprouted some baby roots. Last fall, everyone got potted, [you may have seen my catt question in the fall - it got potted at the same time, same medium, etc. it's doing great!] I used a phal mix from 'RePotMe' and I often pull in just a little moss because in the winter it gets so dry, I like a few little pieces of something that capture a little moisture.

So all these newly potted babies are doing great from October until about a month ago! Plump leaves!New growth! I was getting ready to give a few to my siblings as a memento! Suddenly leaves are yellowing, dropping or shriveling. The medium starts looking like its dusted with charcoal. The moss is no longer yellow but has turned bluish gray. FREAK OUT.

I dumped 2 pots last night and discovered what I feared, roots are gone, the stem is blackish. Carefully gave a long tepid rinse and then spritzed w/ 3% H2O2. Each got plopped into separate glass of water while I reconnoiter. Then I took a couple plants that still looked good but had sketch looking medium. Underneath it all, the medium looked bad and the roots can be salvaged.

So far nothing like this in other Phals that are sitting in pure moss. [Potted the year before - spent the summer outside and were heavily watered but still happy! ] Nothing like this in my other pots. The medium was new and had been in sealed bags but in my garage [temp changes in the summer]. It smelled fine and looked fine when I potted. I am wondering if mold or schmutz from the humidity trays got up into these pots? Has this happened to other people? This is the first year I've used the humidity trays.

Should I consider spraying down the mediums of all remaining orchids with my antifungal [I have the good one ya'all recommend], several times to treat? Was this an overwatering issue only?[miscalculation of having humidity now after wintering orchids in my own personal Sahara for years?]

Your wisdom appreciated.
Pictures are of the swim class, medium of one of my pots that is still intact with a still healthy looking Phal and moss from another Phal pot] I think I should yank and re-pot before things progress 'underground'.

estación seca · #2 03-10-2021, 11:59 PM

What are your temperatures day/night? They are wrinkled, indicating insuffcient watering. They have a good number of leaves so this is a recent problem.

I can't see the medium photo well enough to advise.

Skippersmom · #3 03-11-2021, 12:40 AM

Prob 72 degrees day and night. No real change. Since the 2 shelving units sit right next to the windows and it was 10 degrees for a high and -20 for lows in Febr, the interior temps right next to the windows may have been as low as 68 degrees. A heat vent sits right between the 2 sets of shelves to keep it at 68.

As mentioned, they get a soaking once a week. They sit over humidity, get humidity mist and are sprayed at least once a week in between. We are careful to let them dry out in between but they are amply watered in between.

The roots appear rotted off rather than dried up.

---------- Post added at 11:40 PM ---------- Previous post was at 11:38 PM ----------

On the middle photo, the pink pot, the chunks of medium that appear to have black staining,....that black was not there before.

estación seca · #4 03-11-2021, 10:48 AM

I don't know what caused the bark blackening. It's possible it is fungal. Powdery mildew fungus likes cool temperatures and low humidity. Being right next to a vent means the humidity is probably very low. Water trays with pebbles don't raise the ambient humidity despite thousands of sources claiming they do. Misting isn't useful because it evaporates so fast, and during cool weather it can predispose to rots. Using a humidifier intermittently isn't useful; the ambient humidity drops as soon as you shut it off. Most people who use them run them constantly. In such low humidity and near a heat vent watering once a week probably isn't enough. The roots shouldn't get bone dry between watering. There should be some moisture in the pot between waterings.

I'm not sure what happened to your Phals. If I had to guess it would be powdery mildew and/or not enough water. The prevention for powdery mildew is higher humidity and/or warmer temperatures. I would try to keep them warm and humid until they begin new root growth.

Skippersmom · #5 03-11-2021, 11:14 AM

Thank you for your feedback.

Our misting was mostly constant but stopped for a bit ( a week or so) while we waited for these little demineralization capsules to arrive, as filling our unit with 2 gall of distilled water QOD was going to be a non-starter in the long run. The trays we have are about 1 1/2 inches deep and are full of water with no pebbles. A grid sits on top separating the pots from the water. But open water creates it's own environment for problems too. Prophylactic additives?

A hygrometer sitting on the shelf would typically read about 45% sometimes up to 50% with all trays full and the vaporizer cranking. Otherwise the humidity will be at best 30%. That's really the best 'All My Children' have ever had it since we started on this adventure.

I realized at the outset that these orchids from Dad were quite challenged, but I thought they were over the 'hump'. They certainly live to teach.

Appreciate the feedback.

estación seca · #6 03-11-2021, 04:17 PM

I'm not clear what you mean by misting - do you mean you had an ultrasonic humidifier that emitted a visible cloud pointed at the plants? If so, that's likely your problem. In cool situations Phals shouldn't be misted, especially for long periods of time.

Phals are mostly hot growing plants. They usually survive between the 60s and 70s F all winter but they don't like it. Most people don't know any other way to grow them so they think this is normal.

Growers in cooler houses eventually learn how to keep the plants alive with just enough water not to shrivel, until more reasonable temperatures arrive.

aliceinwl · #7 03-11-2021, 11:55 PM

Often if Phalaenopsis have poor roots to begin with they won’t survive long after repotting, but if the plant is happy they’re usually replaced by new roots as they die.

Misting at cool temperatures (70s) can be counterproductive. At this temperature water can linger in the crown and leaf axils and lead to rot.

Avoid hydrogen peroxide on the roots. Direct application of undiluted 3% hydrogen peroxide can cause tissue damage: it will kill fungus and bacteria but will also kill plant tissue.

What kelp supplement are you using? For Kelpmax use is recommended monthly. If overdosed or used more frequently than directed, I’ve seen some root death.

Are you monitoring moisture in the media? If your Phalaenopsis are allowed to get bone dry between waterings, this can lead to root death or damage. If the roots die and then things get really wet, there will be an explosion of opportunistic fungi feeding on the dead tissue: the trick is to water when the media/roots are almost dry but not completely dry.

I’d repot. If the media is really fungus ridden, new/fresh media is best. Give them a soak in the kelp product and then water when the media approaches dryness. I’d suspend fertilizing until new roots grow in and the plants have a means to take it in. I wouldn’t use the kelp more than monthly. Watering with straight water periodically is helpful because it flushes out fertilizer residues and prevents these from building up.