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Are you sure Perlite is anything to do with polystyrene ? After using it  broken up  in my compost for drainage I was told that these two products couldnt be more opposit . I was told polystyrene is a man made product where as pearlite is a natural volcanic discovery product ?

Now I'm confused! 


Interesting, seems I need to check more, thank you - I thought vermiculite was, is, the natural one and is volcanic - better information need methinks. 

Hi Bookertoo, Ithink I'm going to go with - '' If it does the job then use it '' - none of us can get wrong if we go along with that !  or can we !?


I reckon you are right there lucky3, I'll stick to vermiculite as I have been using it for years and am used to it - seems the best way to go about anything really!

Perlite is made from a naturally occuring volcanic glass which is heated to about 800 degrees when the moisture in the rock causes it to expand rather like popcorn forming little air bubbbles.  It is completely inert but good for both aeration and holding moisture I find it to be superior to the flaked silica of vermiculite as it is much longer lasting in heavy soils



gerrya -  isn't it interesting how different people have different experiences with the same thing?  I have always found that, for me, perlite is the one that deteriorates and goes to powder inthe compost, wheras vermiculite remains inert for donkeys years!!  Guess it doesn't really matter, neither appears to be made in a chemical laboratory and that will do for me, meanwhile we will stick to the product we know best.  Happy, albeit very wet, gardening to all - with perlite or vermiulite as the fancy takes you. 

HI folk,  interesting discussion with reference to vermiculite containing asbestos there cases of vermiculates that do contain traces of asbestos (tremolite) which is mined in Libby Montana and has been subject to a lot of debate in America.

However, generally vermiculite is an inert substance which has been processed to ensure it is safe to use.  If you are concerned I suggest that you check the manufacturers safety data sheet which will clarify the contents and aspects of the material.  This will be free available on the manufactures web-site and should put your minds at rest.


Sorry but free availability is absolutely no guarantee of safety e.g. CFCs, thalidomide and many other medicines, plus trans fats. These are but a few and the list is endless of things being unleashed on an unwary public and subsequently banned and/or withdrawn. A good rule of thumb might be that if you don't know what it is, don't use it. X


In which case Victoria, we would or would not use coffee, tomatoes, and many other things we currently regard as OK - as these and many others have been declared either deadly or carcinogenic over the years - just use carefully and with alot of common sense as we said earlier in this discussion.

Vermiculite is great for the plant roots, for the tiny seeds that need a little light, reducing weight in huge pots - I've been using it for over 25 years and so far it has done me no harm - at least, no harm of which I am currently aware. 

Breathing in any fine dust is never a good idea, use your vermiculite in well ventilated areas, damp it down soon as you've made up the pots and just be a normal, sensible person as the vast majority of us are - enjoy your gardening.  

I think Bookertoo is absolutely right. 

Free availability is, as Victoria says, no guarantee of safety. Yes there certainly are products which were said to be harmless and then have proved otherwise. 

A modicum of sense and careful usage tho should do away with most people's worries. There is no 100% guarantee to life and limb and nor should we expect it.The number of posters worried about growing plants with a reputation for toxicity are increasing - we all seem to be frightened to do or use anything these days and rely on "Government" to tell us what is good, or not so good, for us.

Yes, there are dangers lurking - a walk in the countryside, crossing a busy road, 

If you applied the "if you don't know what it is, don't use it " I can see most processed/fast food going down the toilet - before consumption I should add.......... not a bad thing overall


Isn't that why many of us are gardeners?  So we don't eat quite so many processed foods?

I do so agree about the nanny state telling us how to live, my parents, grandparents etc. never needed a date on some food to tell if it was safe, they applied experience and common sense - something that seems to be a dirty word these days.  Keep us all quiet and under the thumb, much easier to control that way!! Guess what, too many of us won't be 'controlled' for that to work - than goodness.

Regarding vermiculite again, I'm off to sow seeds, with the use of vermiculite to aid the process - the sun is shining, that can be fatal too, but it is too lovely to ignore.


This TedTalk is about the dangers of vermiculite (and the psychology of us humans) It really shocked me because I have been using vermiculite in my raised bed vegetable garden, since I saw Monty use it. What should I do? Get rid of all the soil? And true, I don't have much earthworms in that soil. Is it dangerous for my families health...?

Margaret Heffernan:


==Typical analysis of perlite==[2]

70–75% silicon dioxide: SiO212–15% aluminium oxide: Al2O33–4% sodium oxide: Na2O3–5% potassium oxide: K2O0.5-2% iron oxide: Fe2O30.2–0.7% magnesium oxide: MgO0.5–1.5% calcium oxide: CaO3–5% loss on ignition (chemical / combined water)

All these minerals are naturally occuring in our garden soil. From the break down of what were originally igneous rocks .

There are warnings about not breathing in the dust  when you use it in a commercial setting but in domestic useage it is not likey to cause major issues .

Our soil needs all these minerals. 


These are the main minerals in Vermiculite .
Phyllosilicates Formula
(repeating unit) (Mg,Fe+2,Fe+3)3[(Al,Si)4O10](OH)2·4H2O

Magnesium, Iron Aluminium and Silica.

This material is marginly likely to create more fertile soils than the Perlite as they come from a lava with different chemistry with more useful nutrients.

Where on earth did this  scare originate? . It will do you no harm at all unless you are intending to eat or snort it.


What the H*** is a 'TedTalk' ? 


Coming from a time Vermiculite had not been invented or even thought of as being necessary for raising plants vegetables or fruit in a garden that had fed the family for a hundred years before i was born. I often wonder what happened to that modicum of common sense we are all born with, or not as the case may be. Why use it? Drainage? we used grit washed sand shredded paper chopped straw it all worked in a garden that was essential for feedings us and the extended family. No, well why? to make pots lighter? as a ten year old I would slip a Sack barrow under a large pot and move it easily to where it needed to be, I just do not get it. As an Army Engineer and later a Chemical factory Engineer i could go into most houses in the country and make poisonous gas from what you use to clean the house with, make a bomb from ingredients you store in the pantry, all things you use daily and think nothing of yet very dangerous. The point being we live on chemicals of one sort or another from salt and sugar in foods to medication, our gardens are one large chemical plant changing the soils and feeding nutrients in chemical form to all life growing there. If you do not like the make up of something then do not use it. Vermiculite as with all the other chemical additives we eat or use daily will only kill you if you eat it twice a day with custard.


The only link between vermiculite and cancer causing asbestos was caused by a mining company near  Libby, Montana, as another commenter mentioned, that contaminated vermiculite with asbestos which was mined nearby. This one company, per the website, "was the source of over 70 percent of all vermiculite sold in the United States from 1919 to 1990." So asbestos contaminated vermiculite ended up in vermiculite based housing insulation during that period giving innocent vermiculite a bad rap that just keeps giving.  

More info from



Sometimes I wonder about the future of humanity... For anyone who bothers to read this far.... Use Vermiculite and or Perlite based on its size and not necessarily the purpose they sell it for IE: what it says on the packet. ITS INERT. as in... "its safe to use for the purposes of gardening". Its NOT a "chemical" if you use the word like that and has no "chemicals" in it... It is used where you might use grit or sand. it lightens the soil / compost mix and lets roots grow faster. That's it! I use "Builders" vermiculite intended as insulation in chimneys. It is perfect and loads cheaper than the size graded and over priced bags from the garden centre.  Everything everywhere around you is "Chemical" STOP using it like a swearword to needlessly worry people! I regularly put dihydrogen monoxide all over my garden. I can't help getting it all over myself and the kids. Maybe I should take them to the hospital?

I'm intrigued - what the heck is "dihydrogen monoxide" in common language ?  I suspect I'm missing something here in that if you spread it over yourself as well as the garden and are still alive to tell the tale, it can't be all bad

Either enlighten me or at least give me a clue in the form of why you use it in the garden - please ?


otherwise known as H2O = Water ;-)