Circulation vs. Humidity - Orchid Board

dravenxavier · #1 02-01-2009, 09:11 PM

Well, I've got my 75 gallon orchidarium up and running, and everything's doing pretty well. For those who haven't seen the tank itself, you can look at this thread, here:

http://www.orchidboard.com/community...chidarium.html

When I had everything in the Exoterra, I had one fan, and it was turned on as low as I could get it with a Zoo Med rheostat. Now in the larger tank, I added another fan, and have turned them up to near full power. Especially after coming here, and reading how important it is for orchids to dry between waterings (for the most part, and with exceptions). However, with the fans on, the humidity is around 50%, dropping into the 40%'s by morning (I only spray once in the morning, as the lights come on). However, today I meddled with wires, and the fans were off for about 2 hours...this allowed the humidity to climb to the mid-high 80%'s.

So, would a period of this high humidity be preferable? Perhaps turn the fans off during the night to allow nighttime humidity to climb like it would normally? Or should I just keep it going as I have been? If so, what would be the ideal schedule for this raised humidity? Thanks!

tulasi132 · #2 02-04-2009, 02:10 AM

Sorry, I dont have an answer to this question but I found your pic through this thread and had to ask, what do you have in there so far? Im impressed and would like to start a mini viv but dont know of the smallest varieties.

dravenxavier · #3 02-04-2009, 06:51 AM

Ok, here's the current list of what's in there so far. I might be missing something, though.

ORCHIDS:
Ascocentrum miniatum
Bulbophyllum brevistylidium
Cadetia taylori
Cirrhopetalum tingabarinum
Dendrobium dichaeoides
Dendrobium lanyaiae
Dendrobium lichenastrum
Dendrobium prenticeii
Dendrobium wassellii
Epidendrum longirepens
Lepanthes fiskei
Masdevallia "Copper Cherub"
Masdevallia minuta
Maxillaria arbuscula
Oncidium pumilum (needs some TLC)
Platystele ximenae
Pleurothallis grobyi
Pleurothallis microphylla
Pleurothallis stricta
Podochilus cultratus
Schoenorchis fragrans
Tolumnia velutina (just hanging on)
Trichosalpinx pergrata
Tristella cordeliae
Zootrophion serpentinum

CARNIVORES:
Cephalotus follicularis
Drosera aliciae
Drosera rosea
Heliamphora minor
Nepenthes bellii
Nepenthes ephippiata
Nepenthes lowii
Nepenthes rajah
Nepenthes talangensis
Nepenthes (unidentified hybrid)
Pinguicula cyclosecta

OTHERS:
Hydnophytum formicarium
Neoregelia lilliputiana
Neoregelia lilliputiana x fireball

tulasi132 · #4 02-04-2009, 12:58 PM

Wow. Thats an excellent list. That gives me lots to research for my own viv. Thanks a lot.

Becky15349 · #5 02-04-2009, 02:11 PM

Ok, I'm gonna take a vague stab at this, allbeit a very unscientific one..I kinda talk things out:

High humidity is great for orchids, provided that the air is moving around. Without air movement, you run the risk of rot. Now, if the air stops moving and the humidity increases, how long do you have before rot sets in? That's a good question...maybe a few hours? Maybe a day? I'm not certain - some types may be more sensitive than others.

In thinking you could let humidity build during the day, and leave the fan off for max...4-6 hours? You want the humidity to be highest during the time they are transpiring the most, which is during light hours. I don't think humidity needs to be that high when the plants are photosynthesizing sugars, which is at night in the dark hours, since this is an internal process. Plants are always transpiring, but it is greater during the light hours.

Those are just my thoughts...this was like an essay question in plant phys class

Please don't beat me up!!! Although anyone may question my logic, I am not sensistive, LOL...

Tindomul · #6 02-04-2009, 02:47 PM

I have the fans turn on at night, when temps go lower due to absence of light. These two combined give a combined temp drop of about 10-15 degrees which orchids love. Second, I'm always afraid that fungus will grow in the dark if its too humid, so I turn the fans on at night. Third, I find that orchids suffer a lot when they dont have enough water in the daylight hours.
I run my fan intermitently for a few hours at a time every night, and I don't run it in the day.
So I am assuming that your orchidarium is not sealed in sufficiently to trap the humidity, and it is escaping. If you wanted to, you could maybe work on sealing it some more and then when humidity is really high all the time, you could let the fans run 24/7.

dravenxavier · #7 02-04-2009, 04:46 PM

it's definitely not sealed...in one corner, there's a chunk missing out of the plastic backing to the glass top. Perhaps I'll try leaving the fans off during the day, or at least turning them down, since their basically hooked up to a dimmer switch. My worry about turning them off during the day was that the water would sit too long on the mounts without circulation, but perhaps I'll have the fans run for a few hours after lights on, to get rid of anything excessive, and then switch them off. Everything's been growing pretty well, so I don't know if I should mess with it, though. It's hard to say, since this new setup has only been running about a month and a half.

Becca · #8 02-04-2009, 06:33 PM

I leave my fans on 24/7. I had the same problem, my Grand Cayman orchidarium is not completely sealed andthe humidty was excaping but I know I needed air circulation during the day and night, so I bought a misting system from MistKing and it solved my low humidity problem. The misters are on timers that come on during scheduled times for a few seconds every day and then shut off around 5:30PM to allow everything to dry off before the lights shut off. I also have the misting intervals set up so that the leaves will dry off before the next misting interval comes around. It was a tad expensive, but so worth it!

dravenxavier · #9 02-04-2009, 07:18 PM

I have a misting system, actually, I just need a new pump, as the last one ran dry, and that was that. So this time, I'm going with a diaphragm pump so that won't happen again. However, I don't have the $100 to pitch for it just yet. Perhaps after tax returns come in :P

moos · #10 02-06-2009, 11:28 AM

Hello Dravenxavier,

In my vivarium ,which also contains poison dart frogs, humidity goes to 100 % at night and during the day an average of 70 %. The fan is on during the day for a quarter every hour, but it blows rather than sucks.
So far the frogs and the orchids love it, no rot and funghi.

greetings

moos