Just realized most people are using the wrong soil in their closed terrariums...

I've seen three builds this week where folks used regular potting mix with perlite and it's gonna turn into a moldy swamp within 2 weeks, has anyone else had luck with a simple sand and peat mix instead?

2 comments

2 Comments

the_julia16d ago

Wait, you're telling me people are putting perlite in closed terrariums? That's literally asking for root rot, perlite holds way too much moisture in an enclosed system like that. I've had way better luck with a sand and peat mix too, actually, I tried a 50/50 blend last year and it stayed aerated but still kept enough moisture for my ferns without going moldy on me. You think sealing regular potting soil with all that organic matter in a glass box is just gonna work out fine? That's like putting a wet sponge in a sealed jar and hoping it stays fresh.

the_phoenix16d ago

Hang on, is root rot really that automatic with perlite in a closed system though? I've seen plenty of people use it successfully for years with things like ferns and moss, seems like it just depends on how much you water and what plants you pick. Your 50/50 sand and peat mix sounds interesting for sure, but calling perlite a guaranteed rot fest feels a bit extreme to me. Regular potting soil in a sealed jar is definitely a bad idea, but perlite isn't the same as that - it's mostly just aeration. I think the whole thing about terrariums is more about trial and error anyway, not some hard and fast rule.