I thought the 'activated charcoal layer' was just a fad for way too long

For my first ten builds, I skipped it completely. I figured a good drainage layer of pebbles was enough, and adding charcoal was just extra work for no reason. Then I tried a sealed jar build with some moss and ferns I collected near my place in Portland. After about two months, it started smelling like a swamp, and the water at the bottom looked murky. I opened it up and the soil felt slimy. I rebuilt it with a half-inch layer of horticultural charcoal between the rocks and the dirt, using a brand called Mosser Lee. That was eight months ago, and the same jar is still crystal clear with zero bad smells. It really does stop that rot from setting in. Has anyone else had a sealed setup fail without it, or am I just late to the party?

2 comments

2 Comments

the_mia1mo ago

My first closed terrarium turned into a science experiment gone wrong after three weeks. I finally caved and added the charcoal layer, and now my little fern has been happy for almost a year.

lewis.charlie1mo ago

Watched my friend's terrarium mold over until she added charcoal too.