evtubbergh
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Joined: Sun Jan 13, 2013 6:52 am
Location: South Africa

Identify perlite

Hi all

We don't produce perlite here on any large scale so I cant just go out and buy it but I have seen white balls in the potting soil that I buy. At the time I thought it was styrofoam because it is soft. However it looks like the pictures of perlite that I have seen.

Should perlite be soft like styrofoam or is it hard? I know it would be light but I imagined it to be fairly hard, like pumice.

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vinyl217
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Location: East Central Illinois

Re: Identify perlite

should be hard, wouldn't surprise me if companies cut corners and use Styrofoam though.
"Real tomato ketchup, Eddie?" - Clark W. Griswold

imafan26
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Re: Identify perlite

Perlite is not as hard as pumice, you can still crush it with your fingers. It is porous and light. If you are buying the product in a bag, the bag should list the ingredients.

BTW we do use styrofoam cubes (not the dissolving kind) for orchids. They are loosely put in the bottom of the orchid pots to take up space to use less of the orchid media and provide drainage. Orchids are air plants and would prefer to just hang out in trees with their roots grabbing on to whatever is available. Only people insist that they live in pots.
Happy gardening in Hawaii. Gardens are where people grow.

evtubbergh
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Posts: 532
Joined: Sun Jan 13, 2013 6:52 am
Location: South Africa

Re: Identify perlite

Thanks. I think there is confusion here as South Africa might not even produce it. We would not have any notable deposit of obsidian to use and we already are one of, if not the, highest producer of vermiculite in the world.

I did find styrofoam in the bottom of orchid pots but oddly I was not so bothered by that as it does make sense given the air nature of their roots. On the other hand it bothers me that they use it in potting soil mixes, which by the way do not list ingredients as they do not have to.

Oh well, thanks. I know we import or make some perlite so I am going to buy it for use over seeds when I germinate. That soil will make it into the final mix for pots anyway when I pot up but I definitely won't be able to mix large quantities of perlite and peat for my large pots. (We also import the peat)

I will be trying vermiculite in the near future as a lightening agent although I have always been bothered by the fact that vermiculite breaks down into other clays and that it is a clay itself. Maybe because I have clay soil and I have a horror of clay. (Don't worry, this is for pots, I'm not adding it to clay soil).

evtubbergh
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Posts: 532
Joined: Sun Jan 13, 2013 6:52 am
Location: South Africa

Re: Identify perlite

I found a plant that expands perlite so I bought some but I didn't expect the perlite to be so friable. It reminds me of rice crispies and it crushes into powder the same way.

Is this right?

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