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Sustainable Alternative to Vermiculite

Posted by stephankrasner 6 (My Page) on
Fri, May 20, 11 at 16:39

I love the square foot garden model, but I don't like the fact that it uses vermiculite. Vermiculite, while technically organic and non toxic, is a finite resource. It's a byproduct of mining shale and most of it comes from the same era that mos of our crude oil comes from. Like oil, it's running out at an alarming rate, and I'd rather find a local renewable alternative sooner than later.

I've heard that Texas greensand and Volcanic sand are good alternatives, but both of these are difficult to come by near Seattle. Any suggestions for an alternative in that region?


Follow-Up Postings:

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RE: Sustainable Alternative to Vermiculite

Im not sure how fast its running out, but like peat moss(which some maintain is also running out), you are only doing this one time if you make your own compost. Its not the SFG'ers of the world running this out. By using this only once were conserving it pretty good I think.


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RE: Sustainable Alternative to Vermiculite

Thank you for that information! I wasn't aware that vermiculite didn't have to be replaced/added. Definitely good to know.

It is running out though. If I ever wanted to expand, I'm not sure it would be affordable in the future. Alternatives might be a good thing to have in my back pocket.


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RE: Sustainable Alternative to Vermiculite

I just saw something from a guy in CA that is using something made out of coconut shells. It is an alternative to peat. I have not run across a vermiculite alternative but would love to find one. We can't get vermiculite where I live.


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RE: Sustainable Alternative to Vermiculite

The oil comment needs some explaining. Expanders don't purchase ore from any of the main oil producing countries most of us think of. And there are only so so many mines to get it from. Especially the coarse grade everyone loves.

What I would suggest being an expander of Perlite and Vermiculite is finding a way to amend a portion of your verm with perlite. Use a smaller portion of vermiculite for water retention and perlite for porosity. From what I understand the reason coarse verm is called for by the authors of this type of gardening is because it serves two purposes (water retention & porosity) and they don't like the white perlite because of appearance purposes. Plus it doesn't retain moisture like verm does. But can be acclimated to work together just like many of the commercial soil mixes that most gardeners/ growers have been using for over a century.

Perlite is considerably cheaper and yes more sustainable than vermiculite. Although the finer grades of vermiculite, like what come from Virgina and North Carolina, are abundant.

Plus if you use a finer grade perlite you can open up more area for the perlite to adsorb water because you are providing more surface area for water to attach to from a finer particle vs. larger coarse particle, which is what is used in most commercial potting mixes.

Have a good day!


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