Have you considered just not growing them in there? The conditions are not going to be conducive to good growth and I also believe you need to learn a bit more about terrariums (if you had to ask the question about humidity). Egg crates?

Hi
What type of orchids do you want to grow?? How far do you want to go to make it suitable. ? Most of the usual types need drying periods and of course you wouldn't want seasonal species. That leaves low light warm growers.
Even with these types, most, benefit from day night differential as well as good air circulation.
That's why you're having trouble with specifics. Give us some more info . gary

And just how am I supposed to be an instant expert Lucy, so that I don't have to ask questions?

And yes, people grow orchids in terrariums all the time and they are VERY conductive to growing them and I DO want to make one.

Gary,

I want to grow small Bulbos in there. Like my Bulbo. medusae.

So sorry.

Hi!

This is my first time posting here as a person who can give advice and I am completely excited. I hope I can help. I TOTALLY agree with putting bulbos in a case since they dig the high, high humidity and keeping up that humidity out of a case is tough to say the least. I am still an amateur compared to the other people on this forum, but here goes!

There are a couple of websites that I have found that have been the most helpful. You might LOVE this one since he made an orchidarium out of an aquarium:
http://www.tallyorchid.org/orcharium/orcharium.htm

These guys make beautiful orchidariums and I got some hints there: http://www.orchidarium.com/

I utterly understand your confusion. There is so much information out there that it is really hard to pick a direction to go. By the way, the easy answer to your "egg crate" question/dilemna is that you just want to make your shelves out of something that allows for air circulation. "Egg crate" is the name for the open-work plastic material that you sometimes see under lights in a corporate setting. It is so open that air goes through it and can get to your orchid roots and help prevent fungus, root rot, insect infestations, etc.

So, that brings us to our air circulation question. The fan is a great way to go. I have seen them mounted on the top of the orchidarium and blowing down on plants, I have seen them mounted on the side. I dont think it matters, though I have been wondering about putting one near the bottom to get the humid air that sinks on up to the top of the case. I do think that, since you are setting this up yourself, you could give yourself options. Start with it mounted somewhere easy and, if it works, great, otherwise find another place to put the fan OR simply move your plants around till you find a configuration that works.

I dont know what grow light you are using - so who knows if it will work for your bulbos - but my local hydroponics guy (and lots of information on the internet) says that T5 flourescents (there is a very nifty fixture on their website that might be useable for you if you decide to one day switch to flourescents: http://www.growny.com/index.php?main_page=index&cPath=22_85) are MORE than enough for orchids in particular and give great penetration. (Also, this is what they use in the commercial Orchidariums in the link I included above). They also tell me that the LED technology is close to working, and may find LEDs to endorse within the next year or two.

As for humidity, my bulbos seem to be loving the 70% I get in my 2' case. I assume your aquarium is going to be very air-tight and keep your humidity high/stable so the ultrasonic fogger should be great. My case isnt that airtight, so I went crazy and invested in a misting system. I bought the Rainmaker Junior system off of ebay and I am very happy with it, though I then went a step further and bought nozzles from MistKing because they rotate and are not just cool, they totally make me happy.

I hope all that info helps!

Hi Minnie!

Been a bit since I last popped in here.

1st yes, as you know, you can indeed do orchid in a terr. How big a tank do you have?

A false bottom can be handy but isn't necessary unless you are planning on having a water feature [river, waterfall, pond, etc.] You can still use something like that for a drainage layer if you wish.

For a substrate, it really depends on what all you decide to grow. You can use lava rock or Hydroton/Primagra (puffed clay balls used a lot in hydroponics) for a drainage layer then top with a layer of sphag.

That's pretty much what I've done with my terrariums

To maintain humidity you can do as Julie mentioned and get a misting system, or simply give the sphag and walls a good misting once or twice a day. If you tank has a glass lid, that will help contain the humidity.

PC fans are great for providing air circulation -- & no you don't have to drill a hole through the glass.

Lights ..... you will likely need more than that one light will provide. This will likey call for some trial and error until you find the right balance. I use cfl's in mine.

Hope this helps!

Paul