How do I keep humidity trays clean?

[Country Gramma]

Hi All,

I'm sure I saw some info on this in browsing other threads when I was learning how to set up for indoor growing under lights but I can't find the info now.

My humidity trays need to be washed out completely every week. The water in them gets an oily??? looking film on top of it and just looks generaly yucky.

Can I add Physan or something else to it to keep it cleaner?? And if so in what amounts per gallon should I mix it?

Thanks, Karen

[bodaciousbonsai]

Yes physan is the way to go, it will cut down on algae and other nasty stuff from forming. or you can add 10% bleach with the water. Just be sure to keep covers over the humidity trays such as eggcrate, I did that for years before building my own wardian case

[Country Gramma]

Thanks Bodacious,

That's what I was hoping to hear. I just got some Physan and will put it in at the next cleaning (should be soon).

Love OB ~ Such quick answers. Karen

[Sun rm.N.E.]

Hi Karen

I agree, Physan is probably much less toxic to inhale than bleach, which should not be used without good ventilation in the house.

Just to remind everyone, measurements of the benefits of "humidity trays" to raise humidity show that, in most circumstances, they do not raise humidity significantly for the plants.

There was an article in the orchid society magazine years ago about this, but did not seem to make much of a dent on the popularity of this myth. A better name would be drip tray. So the simpler to clean the better. For this reason, I do not put gravel, leca or anything on the bottom, since it would require more harsh poisons or boiling to kill most of the bacteria and fungi hiding in it after a while. An empty tray can be kept clean with simple detergent. You can even get trays that are dishwasher safe. A lot of people use a grid, like the common ones made for fluorescent lights, on top of the trays to keep the pots out of the water.

I hope this helps.

Addendum: I just noticed there are links to previous posts on this topic on the bottom of this page.

[johnblagg]

you do need to be aware that physan can react with strog oxidisers so mixing it wait bleach would not be advise....read the post about the smoking orchids that was posted recently.

The guy soaked the plants in physan and then rinsed with hydrogen peroxide ...he had smoke? Or at least fumes coming off them.

[herfy]

what i do is use copper wire used in house wiring..it does not allow the algae to start growing.Just get a foot long piece from any local hardware store,stripe the rubber coating off,cut it into 6 inch pieces and stick it in tray.Works for me anyways

[Country Gramma]

Thanks Sun rm. I use an empty tray with the egg crate grid on top raised up by plastic pipe rounds. The water doesn't even touch the bottom of the grates. It may not help the humidity at all but it makes me think I'm doing more for the poor humidity in my house.

Thanks for pointing me to the posts at the bottom, I've never looked there before.

John I did read that post when I was researching and knew about that. Thanks for pointing out a potentially hazardous situation.

Herf, that copper wire thing sounds like something I'll try!!! Thanks.

Everyone has been so helpful.
Thanks all, Karen

[stefpix]

I always had doubts about the humidy increase with some water in a tray. I think the evaporation rate at normal temperatures is so negligible that teh overall humidity does not really change much.
a better way i think is to put an old large / wide pan on a radiator nearby in the winter with water in it or use a wet towel.
the water evaporates in a few hours.

[RosieC]

The main problem with humidity trays as I understand it is that the water vapor that forms is heavier than air and so drops to the floor from the edge of the tray, rather than rising up to the plants. As the edge of the tray where the humid air can escape from is lower than the plants it just falls away and is lost in the size of the room or house, or even larger area.

I've just set up a humidity tray with a lid for a couple of my sick Phals and I'm hoping the lid will mean a better raise in humidity because it is a much smaller space and the only exit for the more humid air is above the orchids not below them.

[stefpix]

rosie
i agree with you
I am thinking actually the humidity tray may be something harmful where bacteria, molds, mosquitos can thrive.

I have a small cool mist humidifier and the mist goes down after losing momentum from the humidifier's fan.

I grow some small carnivorous plants that have to sit in distilled water and i see if i put a lid on the clear box where they are sitting then the humidity increases.
Sometimes I do it for a few hours when teh overall humidity is low and then i see some sort of healthy dew on the Pinguiculas' leaves.
so also on the seedling trays.

if you put a metal tray on a radiator with water in it that is for sure an humidity tray and the water evaporates fast enough and it gets warm enough so molds and bacteria will not develop.

anyway probably having a lot of plants close one to another keeps the air less dry