Soil Additives: Perlite
Regular potting soil is far too rich to use by itself in transplanting office plants. It’s overly dense, loamy, and if you don’t use a soil additive, your plants are highly likely to develop root rot.
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial mineral and a commercial product useful for its low density after processing.
It’s extremely useful in transplanting interior plants, because it will allow the roots to grow and expand without being inhibited by clumps of wet soil. Potting soil naturally retains water and perlite, vermiculite, or some other additive is imperative to keep it aerated properly.
We usually do a 80/20 or even 70/30 mix soil to perlite–we don’t actually scientifically measure it, our way of mixing it is “cookies and cream–more cookie than cream”–meaning perlite is snowy white when mixed in with dark potting soil and resembles cookies and cream ice cream and if you go to mix it yourself, you’ll see exactly what I mean.