# Humidity trays; Algae



## masaccio (Dec 13, 2020)

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.


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## Ozpaph (Dec 13, 2020)

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


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## masaccio (Dec 13, 2020)

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.


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## CarlG (Dec 13, 2020)

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


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## eds (Dec 14, 2020)

Have you got this sort of stuff in the States?








EcoPond Water Feature Clear


Prevents and removes algae blooms in your water feature Made from natural organic products Can be used on features made from any material




www.swelluk.com





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.


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## musa (Dec 14, 2020)

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.


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## terryros (Dec 14, 2020)

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.


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## Duck Slipper (Dec 14, 2020)

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.


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## masaccio (Dec 14, 2020)

CarlG said:


> 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. 



eds said:


> Have you got this sort of stuff in the States?
> 
> 
> 
> ...


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....



terryros said:


> 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. 



Duck Slipper said:


> 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.


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## TyroneGenade (Dec 14, 2020)

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.


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## masaccio (Dec 14, 2020)

Really? Awesome!


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## kitfox (Dec 14, 2020)

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!


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## masaccio (Dec 14, 2020)

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.


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## kitfox (Dec 14, 2020)

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


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## masaccio (Dec 14, 2020)

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!


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## kitfox (Dec 14, 2020)

Latitude? Looks like a white Christmas!


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## masaccio (Dec 14, 2020)

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.


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## SouthPark (Dec 14, 2020)

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


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## Phred (Dec 14, 2020)

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.


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## masaccio (Dec 14, 2020)

Phred said:


> 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?


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## masaccio (Dec 14, 2020)

SouthPark said:


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


Thanks, Southpark. Simple and elegant "solution" for me.


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## SouthPark (Dec 14, 2020)

Most welcome masaccio! Beautiful photo of the snow forest in the background. Beautiful.


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## Phred (Dec 14, 2020)

masaccio said:


> 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?


You're welcome masaccio,
I have 90 humidity trays set up like this and they work great.


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## masaccio (Dec 14, 2020)

Phred said:


> You're welcome masaccio,
> I have 90 humidity trays set up like this and they work great.



Whoa!!! That's amazing!


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## TyroneGenade (Dec 15, 2020)

masaccio said:


> Really? Awesome!


Yes. It is how I control algae issues around the orchids and in my aquariums.


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## Duck Slipper (Dec 15, 2020)

Phred said:


> You're welcome masaccio,
> I have 90 humidity trays set up like this and they work great.
> 
> View attachment 23961


Phred,
I’m guessing you water your plants in these trays? But, don’t have to remove water from trays due to evaporation? Or, do you somehow remove excess water?


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## masaccio (Dec 15, 2020)

Phred said:


> You're welcome masaccio,
> I have 90 humidity trays set up like this and they work great.


Hey, Phred. Have you posted pictures of your setup? I'm very curious about your light source and where you grow. Thanks!


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## Phred (Dec 15, 2020)

masaccio said:


> Hey, Phred. Have you posted pictures of your setup? I'm very curious about your light source and where you grow. Thanks!


Hello masaccio
I grow in the house in a 10'x14' room on metal shelves. I have HO t5 florescent bulbs and cheap LED shop lights... both are daylight 5000K-6500K. A couple fans on while the lights are on. This is one wall of plants... there are two more.


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## NYEric (Dec 15, 2020)

What's the matter with algae?
Nice set-ups. Thanks for sharing.


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## Phred (Dec 15, 2020)

NYEric said:


> What's the matter with algae?
> Nice set-ups. Thanks for sharing.


Hey NYEric
In my experience algae... especially in gravel humidity trays or pots, can attract fungus gnats.


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## NYEric (Dec 15, 2020)

Hmmmmm, I am lucky I guess.


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## masaccio (Dec 15, 2020)

Phred said:


> Hello masaccio
> I grow in the house in a 10'x14' room on metal shelves. I have HO t5 florescent bulbs and cheap LED shop lights... both are daylight 5000K-6500K. A couple fans on while the lights are on. This is one wall of plants... there are two more.



Now let me see, what is the first word that comes to mind. LUST!! I admit, I want to copy that setup exactly.


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## Ozpaph (Dec 16, 2020)

i want to live on your windowsill!


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## masaccio (Dec 16, 2020)

Ozpaph said:


> i want to live on your windowsill!


Well I’ve been thinking about getting rid of the Cattleyas anyway. Just bring along a Paph or two.


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## masaccio (Jan 1, 2021)

Phred said:


> Hello masaccio
> I grow in the house in a 10'x14' room on metal shelves. I have HO t5 florescent bulbs and cheap LED shop lights... both are daylight 5000K-6500K. A couple fans on while the lights are on. This is one wall of plants... there are two more.View attachment 23976


Phred, are these baker racks 36" or 48"? I like the black. Home Depot seems only to have 5-tier black ones in 36". Thanks!


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## Duck Slipper (Jan 1, 2021)

Phred said:


> Hello masaccio
> I grow in the house in a 10'x14' room on metal shelves. I have HO t5 florescent bulbs and cheap LED shop lights... both are daylight 5000K-6500K. A couple fans on while the lights are on. This is one wall of plants... there are two more.View attachment 23976





masaccio said:


> Phred, are these baker racks 36" or 48"? I like the black. Home Depot seems only to have 5-tier black ones in 36". Thanks!


Looks absolutely stunning...I don’t see how you water. Where does your waste water go? How does it drain?


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## Phred (Jan 1, 2021)

masaccio said:


> Phred, are these baker racks 36" or 48"? I like the black. Home Depot seems only to have 5-tier black ones in 36". Thanks!


Hey masaccio
48" x 18" from Lowe's... cheaper than HD.


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## Phred (Jan 1, 2021)

Duck Slipper said:


> Looks absolutely stunning...I don’t see how you water. Where does your waste water go? How does it drain?


Hey Duck Slipper
I carry each tray to the sink and water with a sprayer from a 5/gal bucket over the sink... one plant at a time..


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## Duck Slipper (Jan 2, 2021)

Wow...that’s impressiv...


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## cnycharles (Jan 2, 2021)

Phred said:


> Hey Duck Slipper
> I carry each tray to the sink and water with a sprayer from a 5/gal bucket over the sink... one plant at a time..



If watering from a five gallon bucket always, could use an aquarium pump with water hose attached, might be able to water more quickly


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## Phred (Jan 2, 2021)

cnycharles said:


> If watering from a five gallon bucket always, could use an aquarium pump with water hose attached, might be able to water more quickly


Exactly what I do. I mix 5 gallons of fertigation water and water with a sink sprayer setup on a small fountain pump.


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## cnycharles (Jan 2, 2021)

Oh; I just leave the hose end open


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