Brand new and struggling

[kheftling]

Hi folks!

So I'm the newest of the new. I absolutely love orchids in all their forms and designs, but so far I've proven to have a brown thumb with them. I bought several at Longwood Gardens near where I live and managed to kill them with kindness. I think the problem is that my house is fairly dry and I can't just humidify it for the plants. I tried putting humidity trays beneath them but didn't seem to have much of an improvement.

I've been putting a lot of research into terrariums as it seems a better way of being able to control the environment on their behalf. There seems to be a big movement (which I find cute and attractive) of making mini terrariums out of old glass apothecary jars and putting layers of substrate in with tiny ferns, moss, orchids, begonias, and varieties of other co-habitators.

So I bought a large glass jar, a tiny maidenhair fern, and a miniature oncidium twinkle 'pink profusion'. So...now I'm a little hesitant if this is the right combination, will the oncidium have too much humidity in a small container? Should I leave the top off? top on? pot the plant in the bark material or sphagnum moss or a combination? I would love to fill my home with orchids in happy little terrariums both potted and mounted, but I hate to invest money in lovely plants only to unintentionally kill them all. Any help would be much appreciated!