Bulbo (pink roots), A.Punctata (black root tip) and some leave problems - Orchid Board

blurrycollie · #1 08-31-2022, 04:23 PM

Hello Everyone,

First time user here! I posted the same thread under Disease section, but I figured this subforum is more popular. I will delete the other one.

I recently built a Paludarium/Orchidarium with an automated mister and fan.

The first three residents in the tank are:
1. bulbophyllum purpurascens
2. Aerangis Punctata
3. Dendrobium Aberrans

Apparently each of them are having some issues. So I’m posting here to get some advice.

1. Bulbo - I received this one potted and I mounted it on the drift wood. I begin to see some roots turning pinkish color. I thought this could be a. tannin bleach; b. Normal root transition from potted to bare (as also this species is known for their purple color) or c. Fungus/disease

2. Aerangis Punctata - this one is currently in spike. I noticed one root started with active green tip but then turned into this blackened/rotted color. My guess is that this is either an overwatering where it has too much stand water, or tannin bleach.

3. Dendrobium Aberrans - I got this one with black spots and a few rotted roots from the seller (potted). I cut away the rotted roots and gave it a good soak in the Inocucor solution (diluted). But in the last few days, I begin to see some white patches (probably fungi/non mealy bugs). This one does get all the mist, so it is also possible that standing water is causing this.

I have the famous Inocucor which I’m planning to spray and rinse weekly.

Thanks a lot!

Roberta · #2 08-31-2022, 05:32 PM

First, Welcome!

For the Bulbo, change of color of the roots could just be a reaction to light, moving it from a dark pot to the light. If the flowers are dark, there are likely anthocyanins in the roots that are just becoming visible due to exposure to light (think suntan). Actually, any change of medium can adversely affect roots - the new roots will hopefully attach to the mount but existing roots won't. So nurture the exisitng roots but the ones that will be most productive will be the new ones that emerge in their new environment.

What is a tannin bleach? I hope that you aren't putting any sort of treatment other than kelpack/inocucor. What is the airflow like in your tank? Along with moisture, roots need air.

New roots and new growth are going to take time... orchids don't do anything fast, progress is measured in months not days or a few weeks.

blurrycollie · #3 08-31-2022, 05:48 PM

thanks a lot for the reply!

The root color change is also my guess. I will continue to monitor.

In terms of the flow/setup/airflow, I have a mister (similar to a standard home humidifier but with slighter bigger water droplets) running for 15 mins each hour, and with a fan running for 16 mins to get rid of the excess humidity.

overall RH goes up to 92% after the misting, and then drops to 80-81% RH before the next misting. It is high, so thats why I decided to go bare-roots for them.

I have a full spectrum grow light with around 1500-1600 FC, so it shouldn't be anywhere strong, but I get the root transition point.

Tannin bleach - as this specimen is now mounted on a driftwood ( which was supposed to be used for aquariums). I heard the wood might bleach acidic tannins to make roots darker color. Mostly benign.

Roberta · #4 08-31-2022, 06:15 PM

Try increasing the run-time of the fan. A gentle breeze 24/7 can be very beneficial. That RH is rather high... the Bulbo is fine with it (they like "wet") but the other two need to dry out somewhat. You can manage that difference by adding some more water-retentive sphagnum to the Bulbo and leaving the other two bare-root. Think of these plants in the wild, on tree branches - it may rain a lot, but then the rain stops and they get lots of breeze.

blurrycollie · #5 08-31-2022, 06:49 PM

Thanks a lot. I'm still toying around the mist timing, RH and fan timing. But your advise makes a lot of sense.

As for the Dendro. Aberrans, I saw online (Andy's and Travaldo's) saying that this species likes it humid. But I know I need to monitor how my specimen plays out. This one has been rather troubled since its arrival - I think the high RH did not help on the black spots/Fungi spots. I'm taking on this task to cure it back.

Roberta · #6 08-31-2022, 06:54 PM

Good air movement controls a lot of fungal/bacterial problems that thrive in overly-wet situations. Humidity is one thing (mostly good), stagnant air quite another (often bad). Even in the steamiest jungle, there is good air exchange (even without wind, it's the great outdoors).