Rodger Whitlock totototo@telus.net
Tue, 02 Jul 2013 16:46:05 PDT
On 2 Jul 2013, at 15:33, Ina Crossley wrote:

> I am using pumice in my mixes, but only recently.  I bought the 7mm one 
> which seems to have a lot of dust and small stuff in it.  Does it still 
> do it's job of drainage with all the small stuff filling any gaps.

If you intend to pot up a plant in nothing but pumice, be sure to wash it. I 
have found that otherwise, the fines are washed down to the drainhole, pile up 
against the piece of fly screening I customarily put over the hole, and block 

Pumice by itself is a very good potting medium for certain plants. I use it for 
Weldenia candida (which happens to grow natively near the tops of Central 
American volcanoes, according to the literature), and a few honest-to-God high 

Pumice is actually quite nutritious in a limited sense, containing a lot of 

You are justified in your unhappiness with this supposedly-washed pumice you've 
been sold. Even when it's going into a potting mix, I wash it first over a It's 
shocking how much fine material comes out.

Rodger Whitlock
Victoria, British Columbia, Canada
Z. 7-8, cool Mediterranean climate

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