Hi Sharon,

If you haven't already done so, I'd recommend using the "Search" function on this forum. There's a great deal of good info and inspiration to be found.

Vermiculite is an inert material and should pose no health risks to you or your kitties.

Media options are legion -- depends mainly on what type of plants you have in mind. Just avoid anything with fertilizer already added. You can even use sphagnum moss as your media -- again, depending on the plants chosen.

forgot to add ............

Stagnant environments tend to be very good breeding grounds for fungi and some bacteria. Therefore, good air circulation can help minimize issues with these organisms.

Also good air circulation tends to prevent condensation build up/fogging on the glass msking it easier to see the plants therein.

Paul, thanks for the info. I have searched around a bit on the forums.

So when you note that the media shouldn't have fertilizer added, I assume you mean that things like Miracle Gro potting mix would be out. Generally I've used that for other plants I've grown (houseplants, outdoor potted plants, etc.) so anything else is new territory for me. I honestly don't know what I would put a maidenhair fern and moss in other than a standard potting mix. That's the sort of information I'm trying to find, as I realize that giant thick layers of potting mix are going to lead to the fungi you mention.

I should note that when I first started experimenting with terrariums, I got directions from interior design websites - which apparently did not have the best tips strictly from a plant care point of view.