Sponge rock, also known as Perlite, is a great ingredient for do it yourself orchid potting mixes. It's light weight and inert, so never breaks down (although it does crush). And while it is non-moisture retentive, it's full of all sorts of little holes and crannies, which hold water that is then released slowly as it evaporates. And
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Everything was perfect when it came to shipping and my plants love it
M
Matthew · May 2, 2026
Great company
I've been super pleased with everything "orchid care" that I have ordered from this company! It's my first choice now!