Humidity trays; Algae

[masaccio]

I'm not a humidity tray person usually. In this case I'm using them to deflect heat waves from a radiant heating strip under the window away from the ridiculous numbers of aerial roots my cattleyas are producing. The trays extend a few inches beyond the window ledge; it should work reasonably well. So as long as I had the trays I added some river rocks mixed with Aliflor (expanded clay pellets). About the water: algae will be a problem. I'm wondering if it would help to add, like a teaspoon of Clorox per gallon of water I use in the trays? Any thoughts? Thanks! I should say that all of the plants are in saucers or lifted away from contact, but some of the aerial roots will be straggling down into the pebbles.

 

[Ozpaph]

just wash them out or let them dry out intermittently.
I wouldnt use bleach.

 

[masaccio]

Thanks. Yes, I could keep it just wet enough that the trays would dry every two or three days. No pool swimming. Just a little shallow wading.

 

[CarlG]

Swimming pool algicide, or Physan/Consan (pretty much the same thing), perhaps a ml per tray.

 

[eds]

Have you got this sort of stuff in the States?
https://www.swelluk.com/aquahydrote...A3vTFsK2UiEzozUP3KHrGLDQX1VZ7a6hoCD_EQAvD_BwE
Made from barley straw extract so shouldn't cause any harm, even to roots that may grow down into the water.

Forgot to say I do use humidity tray during the winter when my orchids are on a windowsill. I don't find algae is an issue but then the clay balls dry out pretty quickly as the trays are heated.

 

[musa]

I don't like the idea of putting anything but water in my trays while orchids are standing on them. I clean them once a year and don't care for algae in between.
BTW for cleaning the grids I don't use a toothbrush, I just soak them over night in an overdose of chloride for swimming pools. In the morning they are clean as new without moving a finger.

 

[terryros]

I agree with being careful. I recently put a little too much concentrated Zerotol HC, which is a combination of hydrogen peroxide and acetic acid, into my trays to suppress organic growth. I am sure it worked for that, but it also generated too much gas (probably peracetic acid) that gave brown splotches on tender-leaved orchids like Phrags and Miltoniopsis. Putting in a more dilute solution doesn’t do this. A fine line between what you are trying to kill.

 

[Duck Slipper]

I went to a local heat/air retailer and had them make custom drain pans that fit on 3 different sized tables. Catts., Paphs. and Phrags. all sit on brick supported grids. All the water drains. This saved a HUGE amount of time watering.
It also helped with the indoor humidity problem. Yes, algae grows in the trays. Periodically I pour a five gallon bucket of water with about 1/2 cup bleach in to the trays and the water clears up in a few hours.

 

[masaccio]

Swimming pool algicide, or Physan/Consan (pretty much the same thing), perhaps a ml per tray.

Great, Thanks! This is definitely on the right track. I may even have some Physan.

Have you got this sort of stuff in the States?
https://www.swelluk.com/aquahydrote...A3vTFsK2UiEzozUP3KHrGLDQX1VZ7a6hoCD_EQAvD_BwE
Made from barley straw extract so shouldn't cause any harm, even to roots that may grow down into the water.

Forgot to say I do use humidity tray during the winter when my orchids are on a windowsill. I don't find algae is an issue but then the clay balls dry out pretty quickly as the trays are heated.

We don't seem to have this particular product. I wonder if there are restrictions against shipping it across borders. I've been wanting an outside water feature....

I agree with being careful. I recently put a little too much concentrated Zerotol HC, which is a combination of hydrogen peroxide and acetic acid, into my trays to suppress organic growth. I am sure it worked for that, but it also generated too much gas (probably peracetic acid) that gave brown splotches on tender-leaved orchids like Phrags and Miltoniopsis. Putting in a more dilute solution doesn’t do this. A fine line between what you are trying to kill.

Good point! I would never have thought about additives making harmful gas.

I went to a local heat/air retailer and had them make custom drain pans that fit on 3 different sized tables. Catts., Paphs. and Phrags. all sit on brick supported grids. All the water drains. This saved a HUGE amount of time watering.
It also helped with the indoor humidity problem. Yes, algae grows in the trays. Periodically I pour a five gallon bucket of water with about 1/2 cup bleach in to the trays and the water clears up in a few hours.

Oh good! So I'm not crazy!

Thanks for giving me lots to think about. Options always make life a little easier.

 

[TyroneGenade]

Hello,
You can use plain hydrogen peroxide from the pharmacy. Just pour or mist with it on a regular basis. That will deal with the algae etc... If you have real problems, add a drop of Dawn detergent to break surface tension to wet everything more thoroughly.

 

[masaccio]

Really? Awesome!

 

[kitfox]

Just go to an aquarium store and get some black aquarium gravel. Algae won't show, even if its there. And you will look like a cool and trendy orchidista!

 

[masaccio]

Ha! I really was going to do that. But I had polished river rocks and aliflor already, which I mixed together. I guess I'd call it "reasonably attractive." The "humidity trays" aren't the bona fide ones, they're just half-sheet pans. So hopes for a trendy look went by the wayside fairly early-on.

 

[kitfox]

Now that is a cool (!) picture! And a beautiful setup...what direction is that?

 

[masaccio]

Thank you! It's about due northwest. During the longer days there's a fair amount of mid-to-late afternoon sun. Annoying if I want a nap!

 

[kitfox]

Latitude? Looks like a white Christmas!

 

[masaccio]

About 41 degress N. It was a gentle snow with little accumulation, although it lasted most of the day. A little early for the heavy duty storms; weather has been a little wonky so far. Big storm heading our direction on Wednesday but it might stay coastal and miss us. I have my trusty generator ready to hook up tomorrow just in case.

 

[SouthPark]

Not sure if it will work for you, but could also consider Ray's method - see this link here.

 

[Phred]

Cut lighting egg crate the size of your trays... no pebbles. No need for any chemicals and if you want you can clean them once in a while. If you had an extra one on hand you could change one out and clean the dirty one when convenient.
I have used either peroxide, physan-20, bleach or Zerotol 3.0 (1 tbsp/gal) in trays with no I'll effects. BTW - Zerotol 3.0 is peroxide that is stabilized with peroxacetic acid. I've watered compots with 1tbsp/gal with no I'll effects. The dose for orchids is 1-2 tbsp/gal. It does lower the pH pretty good so do some testing before you use it.

 

[masaccio]

Cut lighting egg crate the size of your trays... no pebbles. No need for any chemicals and if you want you can clean them once in a while. If you had an extra one on hand you could change one out and clean the dirty one when convenient.

Thanks, Phred! Beautiful Cyp. you have in your ID photo, by the way. I like the egg crate idea. I'm okay with the humidity trays for now - until maybe I go "custom" one day - but the egg crate would be grate to place over my sink so I can rest orchids on it while watering/draining. It looks very sturdy. I've been hearing about it forever but had forgotten about it, and never did know where people got it. Where can this stuff be had?