Subject: Re. soil testing
From: "Bill Robinson" <roseguy@flash.net>
Organization: Massachvsetts Institvte of Technology
Date: Thu, 23 Apr 1998 08:50:49 -0700
Message-ID: <MOD$980423.29568@rec.gardens.ecosystems>
Tamsin wrote,
> I planted my first vegitable garden last year and everything turned out
> fine . . . My concern is there might be something lurking there from
> previous owners. . .should I get my soil tested ?
I know of one situation in which a gardener was puzzled as to the poor
growth in one part of her garden - had her soil tested and it showed that
the soil in that trouble spot was very high in lead. As long as "everything
turned out fine" in Tamsin's garden, soil testing for all of the various
problems
probably couldn't be justified. It would be righteously expensive and the
good garden production suggests that it is unnecessary.
To the larger issue of testing the soil for levels of conventional
nutrients,
the laboratory answers are going to come out in terms of chemical
additives-
how many pounds of potash, etc. to bring the soil up to some suppossed
standard. A much more realistic way to go is to work at building the organic
content of your soil up to 20-25% by volume in the top foot or so. Put your
soil tresting dollar into finding the organic content of your soil or do it
yourself
as spelled out in our FAQ at http://sunsite.unc.edu/rge
If your organic content tends to be on the shy side of the 20-25% figure,
add a layer of compost or composted manure as a mulch and let the earth
worms take it from there. If your organic content is at 10% or lower, your
mulch layer should be somewhere around 2" thick. If your organic content
is at 10% or higher, the mulch layer should be closer to an inch thick. Feed
your garden once or twice a year with something like fish meal, kelp meal,
fish emulsion and these ocean based materials are rich in both the macro and
micro nutrients.
Rodale made a major point out of feeding the soil organisms as the best way
to feed the plants. See Session #2 on Soils and Session #3 on Composting
and Plant Nutrition in the Organic Gardening Class Series in the FAQ. I
really
believe that Rodale was on target.
Bill