There are a few plants called "Irish moss" .... what is the real (scientific) name?

It's scientific name is SAGINA SUBULATA

I don't see this doing well in a terr but can't hurt for you to give it a try.

Your terr wall would have to have pockets of soil capable of remaining moist but not sopping wet. Sagina, as I recall, does not like to dry out but doesn't like soggy soil either. (This is especially true at the seedling stage.) You will have to provide very good lighting while avoiding excessive heat as well as good air circulation.

Hi
I grow them in winter in drip trays but find them to be annual. They won't tolerate my summer heat, humidity.
Would think they'd be a poor terrarium plant but have never tried them. Definitely not epiphytic they need the soil.
Good luck gary

I am growing it in a greenhouse, i just couldnt find greenhouse forum . sorry :(

It's a very nice ground cover. It looks nice between stepping stones. I'd plant a bunch of seeds at once if you have enough. You could always thin them out.