GardenBanter.co.uk - Serpentine soils?

James wrote:

I just bought a house on some acres on El Dorado County, California.
What are your experiences with Serpentine soils? I am on a ridge with
red soil full of green rocks. I understand Serpentine soils are high
in heavy metals. ..."Food crops and livestock are susceptible to
picking up and even concentrating heavy metals - a factor to consider
especially if grown for consumption..." So, I am considering building
raised beds and bringing in better soil for my vegetable garden. Also
how concerned should I be about asbestos?

Thanks,
James

James,

I wouldn't recommend that you try crushing any of the serpentinite for
gravel, but otherwise I wouldn't worry too much about asbestos. The risk
is in when you realease the fibres from the rock and then breath them.

Red soil is a good sign: you have a lot of iron, so it should be
relatively fertile. At a guess I'd say that you have a clay or clay loam
soil? Either way, you should try to start with green manures to try to
get organic matter into the soil.

Raised beds would be a good way to go, especially if you have a lot of
clay in the soil. You only need raise then 4" or so, which will reduce
the amount of soil and water you need to input. Look into finding
mushroom compost and using that over a layer of newspaper and then one
of hay as opposed to buying soil because that should be a more
economical solution, in addition to providing more fertility than bought
soil.

If you're having trouble thinking where to begin, you may like to try to
find a copy of Rosemary Morrow's Earth User's Guide to Permaculture.
This is a very user-friendly manual that will get you thinking about the
best place to put things such as trees and your pond with regard to the
topography and prevailing winds, and also to maximise water retention.

Tara