[permaculture] rock dust, need help filtering the hype from the facts

nepal nepal.roade at googlemail.com
Wed Feb 18 17:39:57 EST 2009

On Thu, 12 Feb 2009 22:56:53 -0500
Keith Johnson <keithdj at mindspring.com> wrote:

> Wendy,
> Depending on the fineness of the material you are working with, the 
> relative abundance of soil organisms, and the preexisting health of
> your soil, the material you apply will have varying amounts of
> availability to plants. I've learned that the best way to use rock
> powders is to apply them more often, every couple weeks or monthly,
> in smaller doses rather than one big annual meal. 

My lessons have been different. 

> You wouldn't sit
> your kids down to a table with a year's supply of food and tell them
> to have at it. You shouldn't do it with the garden either.

Have to voice disagreement with this statement. Firstly we are not
talking about children, but feeding the soil. They are entirely
different and have entirely different requirements/needs.

Rockdust is something we do to the soil, not to the plants. The health
and robust nature of the plants growing in such soils is merely (and
happily) a side effect!!

If we look to Nature for insight on this, one of Her ways is through
such natural methods as volcanic eruptions which tends to be a massive
loading of the soil with rock minerals. Or flood and inundation. These
tend to be very long term mineralisations lasting centuries.

I wonder Keith if you have done any controlled trials of growing
plants using bit and piece applications of rockdust as you suggest,
alongside crops grown in a thorough remineralisation of the soil and
then run those crops over a number of years for comparison?

(now back to quietly lurking)

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