Personally, I really hate to use harsh chemicals, and would be especially hesitant to do so in a terrarium or on plants destined for a terrarium, regardless of whether I wanted animals in that terrarium or not, because any chemical residue will just sit there forever, unable to be flushed out. Also, unless you can purify the air in your terrarium as well as the soil, you are pretty much guaranteed to get mold. I don't know why this is, but have found it to be so. Interestingly, my bark substrate has never shown any signs of mold. Perhaps you could grow these sinns. in a finely shredded cedar bark mix? Moss all over the substrate also seems to help prevent mold, though this is not a guarantee, and it would also eventually grow all over your plants, possibly overwhelming them (unless you picked it off regularly). Another option is to leave a small crack in the top of your terrarium to allow some fresh air in. I have found that if the crack is small enough, the humidity still stays nice and high, but you do also get some fresh air in there. I really don't know how to get the mold off the plants though. Air circulation is the best way to get rid of mold, but it could kill the plants, since they are used to (and need) more humidity. And even then, fungus isn't ever really 'dead', just dormant. I would try a bark substrate. I don't have a single spot of mold on mine. Hope it works out for you!

I agree with sahoyaref. I used to leave mine a crack open till I got 2small computer fans in it, but, unless you have air circulation, you will have mold.
I would use peroxide on your plants, is non chemical and does the job for me. Do not dilute, just put it in a spray bottle and spray them.
Ana :)

Hi Ana,
When you mentioned peroxide, are you talking about Hydrogen Peroxide? Theresa