Organic potting soil "white pebbles" question

[DreamWeaver8]

Well im starting to gather up my supplies for my vivarium and while i was looking at all natural/no additives potting soil, since im adding living plants, i noticed some small (around 2-3mm in size) white pebble like things. I think these are some sort of fertilizer or something along those lines for plants but im not sure so my question is will they harm my centipede when i put him in there or should i find something else to use?

 

[xhexdx]

If it's an all-natural soil, then it's probably just perlite. It shouldn't be a problem for your arachnids.

 

[DreamWeaver8]

Wow I feel really dumb, I always thought those were some sort of water activated "fertilizer beads" anyways thanks for the help.