Setting up my first orchid terrarium
 

I've just begun my first orchid terrarium. I wanted to document my progress here and also ask a few questions. I'd be thrilled with any input or suggestions.

First question: I have two 15 Watt tubular fluorescent bulbs (equivalent to two 75 Watt incandescents) and the tank height is 25". I want to be able to bloom Dendrobiums, Tolumnarias and maybe an Slc, so will that be enough light?

Second question: are there any recommendations for a general-purpose substrate in which I could grow paphs, jewel orchids, some ferns, a nepenthes and a begonia? I was thinking of cypress mulch mixed with sphagnum, or I heard of something called jungle mix available at pet stores, but I'm open to suggestions.

Third: I have heard of people having problems with "water walls" or waterfalls flowing down the back wall of the tank. Would I be more advised to go with a mister rather than the small fountain pump I'm intending to get? If I do stick with a fountain pump, will the running water coupled with air circulation create the desired humidity?

My setup is as follows:

5-sided tank (not sure how many gallons, as I purchased it used) 25" tall, longer sides are 22" each

I'm making the cover:
2 fluorescent bulbs
aluminum foil behind the bulbs to reflect the light down
2 computer fans, both mounted at the back of the tank, one facing up and one facing toward the front
Vent holes drilled along the three front sides of the tank and above one fan to create circular air motion and keep the front clear of moisture

The background:
Black silicone
Great Stuff
Oak and cedar pieces of worn wood
Bed-a-beast or similar material to cover the Great Stuff

Substrate:
1" sections of pvc pipe, covered by fine mesh
a thin layer of activated charcoal
some sort of orchid mix

A small fountain pump with a tube up the back wall of the tank to create a waterfall

During the day I'm going to close off the vents and just circulate air within the tank to bring heat and humidity up, and during the night I'll open the vents and create a circulation of air with the room to lower the temperature. I'm hoping to get a nighttime temperature of 65-70 and daytime of 80-85.

Plants I want:
Aerangis biloba
Dracula lotax
Goodyera hispida
Haraella odorata
Ludisia discolor
Macodes petiola
Paphiopedilum delenatii
Phalaenopsis equestris
Phalaenopsis violacea (I've always loved this)
Restrepia striata
some Tolumnia hybrid
Nepenthes bellii
a miniature begonia
a few Tillandsias
a selaginella
a climbing fern
a maidenhair fern

I'm intending to buy plants from Andy's Orchids, Mountain Orchids, Orchids by Hausermann and Black Jungle - has anyone dealt with these places?

I hope my descriptions make sense - once I start putting this all together, I'll post a bunch of pictures.

EDIT: I've changed the plant list to accommodate lower light

I would incorporate a fogger or mister instead of the water wall if it was me. You will also want to have a small fan circulate the air inside. I don;t think your lights are bright enough and especially for Dendrobiums to flower. I have purchased plants from all you mentions and was happy with all except I find Black Jungle's plants to be small, and poorly rooted for the price.

I think your orchid selection may be too broad and some may not like the conditions. But, there will be micro climates in even a terrarium this size so you may be able to site them so they do well. One thing for sure to do is allow for some means to drain excess water from the tank. You will be happy you did so.

A water wall will produce plenty of humidity (especially with a fan circulating air, which you really should have no matter what you do), but a simple "pond" with an ultrasonic fogger in it is probably simpler to set up.

I have a 4'x2'x2'1/2 terrarium in which I grow mostly Draculas and Masdevallias. With a layer of water approx 1" deep in the bottom with a small 12V muffin fan blowing diagonally onto the water and a small blower fan circulating air I was able to maintain humidity upwards of 90%, 90% of the time. The only reason I'm not doing that now is because my DIY tank tore and leaked all over the place.

I look forward to seeing how this pans out for you. Best of luck with your project!

After consideration and given the lights that I have, I'm deciding to go with lower light plants only for this tank - warm-growing Paphs, Phals, Angraecum, etc. I'll modify my plant list when I've solidified a little.