My dad swore by putting gravel in the bottom of terrariums, wasted 2 months proving him wrong

So my dad told me I had to put a thick layer of gravel at the bottom of every terrarium for drainage. Said he'd been doing it since the 80s and it was foolproof. I followed his advice on my first 3 builds, and all of them got moldy and nasty within 3 weeks. I finally got pissed off and tried skipping the gravel entirely on my next one, just using charcoal and a good soil mix. That was 4 months ago and that terrarium is still thriving with zero mold. Turns out the gravel just creates a water table that soaks the roots anyway. Has anyone else gotten bad advice from family members that you had to unlearn the hard way?

2 comments

2 Comments

faithbaker1mo ago

The gravel layer does create a perched water table if you don't get the math right. But I've been using it for years and never had mold issues. You have to make sure the drainage layer is at least 2 inches deep and separate from the soil with mesh or filter fabric. My dad taught me the same method and my terrariums go 6+ months without problems. Sounds like you might have had too thin of a gravel layer or the soil got mixed into it.

parker_bailey1mo ago

Yeah same here! Switching to a thicker layer of the big pebbles fixed it for me.