It's often used as insulation. Perlite is 'closed-cell' and doesn't absorb water like vermiculite (also used as insulation), so there is probably less chance it would have been treated with something to make it water-repellent, but I would still ck it out to be sure.

Al

I found that this perlite is very fine, similar to sand.
Will this work or do I need the course perlite. Seems like everything in mixes I've seen is course.

Thanks

I prefer coarse in the 5:1:1 mix and consider it a requirement if it's substituted for the granite in the gritty mix.

Al

Okay, I'll keep looking.

Thanks

is horticultural perlite different than something labeled coarse perlite (and sold at a garden center)? only reason i ask is that the first was about $12 more than the second (maybe that nursery was just that much more expensive)?
Thanks

Anything you buy at a garden center or plant-related operation is probably going to be fine. I know they treat vermiculite with water repellents when it's going to be used as insulation, but I don't know about perlite. The price of perlite varies A LOT. I buy from a wholesaler that repackages 60 cu ft bags on pallets into 4 cu ft bags for $10/4 cu ft ...... and I have to believe the bags are worth at least a buck/ea??

Al

it was $30 for 2cu ft of labeled horticultural perlite at a garden center. That seemed really high (and it was in a seemingly rural area of MD)

That does seem quite high. I saw it last year for $17/3 cu ft @ a local greenhouse operation.

Al

Horticultural grade perlite in large bag 10kg (approx. 22 lb)-no idea how many cu ft & it costs $30 in Toronto (large garden centre)...

{{gwi:9204}}