You can buy a much better quality perlite which has been further heat treated and has virtually no dust or fines. it costs about double the regular stuff, and is available at 'grow shops' that cater to the cannabis industry. Diana > I can tell you for perlite with fine particles, it was bad news in the way I used it. The stuff coming from the big box stores here in New Jersey, USA, is loaded with dust and fines, the brand M******Gro has really gone to sh*t. > > I had used it primarily for Cypripediums, mixed with other inorganic material or cactus,palm,citrus potting mix. Even after being sprayed down and washed through a sieve outdoors, whereupon it loses half of its volume, I found that its addition turned the mix late in the season to a solid concrete like consistency, completely unfriable in one thick clump with no air spaces. > > Bonaventure Magrys > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >