perlite question

[rcb]

I have gotten ahold of a large bag of perlite. Size is a little bigger than the stuff sold in garden centers. But it's not sold for horticulture. It does state on the bag food chemical grade.

My question is, do you all think it would be ok to use in mixes for my Hoyas and orchids. It would be mixed either with coconut coir for the hoyas, or with spag for my Catasetums, or with CHC for some various other orchids.

Is there any difference between horticultural and industrial grades, not size, but impurities? If so, would washing/soaking it a few times with MgSO4 help and make it usable?

[janet_a]

food grade perlite?? -scratching head- i guess my concern would be that it might dissolve...

[edgy]

This is a good site to check out.... Perlite Filter Aids by looking at it, it would appear to me that it should be fine for horticultural purposes.

[edgy]

It appears that the make up all cases is the same. What distinguishes it as different grade is the density and the porousness of the material. It is a form of natural glass, it is classified as chemically inert.

[orchids4me]

Originally Posted by janet_a

food grade perlite?? -scratching head- i guess my concern would be that it might dissolve...

Lol that is exactly what I did when I first read this thread this morning before anyone replied (scratching head) lol. I had an appointment so I didn't respond yet lol
I'm glad edgy found that link : )

[JLu]

Perlite is essentially popped sand. It is mined and heated to vaporize its water content resulting in a popcorn type structure. It's about 3/4 sand (silicon dioxide) with several other metallic oxides as naturally occurring contaminants. It's virtually insoluble (that's why it was solid in a wet mixture in the first place). It's a high volume, mined material with many, usually low cost, low grade, uses like filter aids or horticultural diluents to prevent compaction. Food grade or medicinal grade materials may have been approved as free of pathogens, but the very process of heating the material to pop it should take care of that.

Use it.

War Eagle!!

[berniep]

G'Day Renee

I'D use it, but please be careful of the air born dust (carcinogenic).

Cheers
Bernie

[rcb]

Thanks everyone. Will go ahead and use it. Bernie, yes I'm aware of the dust hazards, thanks will be careful.

The bag is large, it's probably a few years worth.

[edgy]

hey...the question had me curious for whatever reason.....so I made a call to the Shundler Company.....manufacturer of Perlite. I was told that the difference in grade is related to the size of the particle or coarseness......food grade used for filtration is a finer particle....horticultural perlite is usually very coarse. You'll be fine.....

[janet_a]

is perlite carcinogenic (other than the physical issue of inhaling dust)? i thought it was vermiculite than was the problem... (or does vermiculite have asbestos in it?)

[JLu]

Janet, the answer is basically no, perlite is not a carcinogen in the sense of a chemical that can cause long term cell damage and change. However, neither is asbestos. Asbestos is a needle like crystal that is essentially insoluble and not chemically harmful, but it gets in the lungs and stays. It irritates the sensitive inner layers of the lungs and can often cause lung cancer usually from long-term, chronic exposure.

Silica (silicon dioxide) is sand and glass and perlite. It can be dangerous from chronic exposure resulting in silicosis which is similar to black lung. Coal miners suffer from either or both conditions which reduce the lungs ability to absorb oxygen. This is largely a mechanical effect. Apparently it can also cause the same mechanically induced cancer as asbestos in some cases.

If you have ever stuck your head in a bag of perlite and inhaled dust it can set off a mighty coughing fit, but you are not likely to suffer long term consequences from it. It should be avoided because when you breathe it, it stays with you from then on. There is no getting rid of it. You certainly would not want to do it continually. You also should not be afraid of it. Just avoid the dust. It won't jump out and attack you at night or anything.

[edgy]

perlite is inert....

[janet_a]

thx all; i have a small bag of #3; it was well washed when i got it and i use it very minimally. dealing with large volumes every day could clearly be a problem though.

i think this is what i remembered seeing about vermiculite (non-agricultural use)

Vermiculite | Asbestos | US EPA

[Stitz]

Originally Posted by janet_a

thx all; i have a small bag of #3; it was well washed when i got it and i use it very minimally. dealing with large volumes every day could clearly be a problem though.

i think this is what i remembered seeing about vermiculite (non-agricultural use)

Vermiculite | Asbestos | US EPA

Janet, I don't worry about the bagged contamination. We have enough common sense to protect ourselves. I purchased two different sizes of perlite in boxed, 2 cu ft quantities.

My concern is with the "floating" asbestos from the Rockville Crushed Stone "mine" nr Rte 28 & Shady Grove Rd. I have read that the "strands" are hundreds of yards long -- floating in the wind!!!

--Stitz--

[Bolero]

Yes be careful not to breath in the dust. I would rinse it using a sieve of some kind. I use a rice food sieve to wrong off the perlite.

It will be fine, I user a larger grade one and it works great. I am using a lot of it with my Catt's and just smaller amounts mixed with barks for all my other plants. It is working well even though it's more coarse than some of the agrictultural ones.