Re: no-till gardening

I think I can say with all honestly that Santa Clara clay is
far worse that any found in Berkeley, having gardened in both
places!  Our local clays are the best worst soils you can get
'stuck' with (pun intended!).  They are naturally very rich in
nutrients (since they don't leach out!).  It is just the
texture and lack of drainage that are the problem.

If you have a real drainage problem - i.e. you have standing
water for days after a rain or spots which almost never dry out,
then investigating some simple drainage technology would be
advisable.  This should be done first, before developing and
planting an area.  The winter rains should have already
brought out whatever problems you might have.

One of the problem with clay is that it really resents
being tilled.  You have to catch it at exactly the correct
time - not too wet, not too dry.  Otherwise, you can do more
damage to the soil texture that good.  I have seen it over
and over again - test plots adjacent to each other, one
heavily tilled and amended, the other merely mulched on
top.  The former gets off to a better start, but the latter
often does far better over the long run, if the other is not
mulched as well.

One of the best methods I've seen is to start with a top-
dressing of compost directly on top of the soil.  If the
soil in question is already very compacted from foot traffic
or some other use, it should be gently spaded to open it up
a bit.  The put about 2-3 (or more) compost on top.  Put
about the same amount (or more) mulch on top of this.  Mulch
should be a good mixture of material - leaves, lawn clippings,
shedding trimmings, chippings from a tree company, etc.
Whatever you can get in quantity and the more types the better.

After a season of this settling in and rotting down, the clay
will have opened up quite a bit and should be more routinely
moist due to the effects of the mulch.  You can now pull back
some of the mulch and till in the compost.  Apply more
compost and they reapply and refresh the mulch.  Keep a
permanent mulch of 2-3 inches (or more) on the soil at all
times.  You can add gypsum to our clays to help bond the small
individual particles of clay into larger particles, making for
a more loamy texture.  This will take a number of years to see
any effect, but an effect you will see is you apply the gypsum
every 3-6 months during that time.  You cannot really put too
much on.  It is not toxic.  But it works slowly.

If your pesticide and herbicide use is minimal or absent, you
will notice a florishing of microbial life in your layers of
mulch and compost.  As things balance out, there may be flushes
of some type of fungus or some other type of organizm - these
will pass over time.  Ultimately, all of this activity will help
your plants grow better and keep pathogens at bay.  A good mix
of soil life helps prevent diseases before they start.

You may notice some chlorosis at the beginning of this process.
This is due to iron being temporary lost to the composting
process.  It is later returned and this effect will balance out.
You may also notice snails and slug might abound - this will also
be more dramatic at first, but you will likely need to still
investigate ways to deal with these mollusks.  Interestingly, a
new iron sulfate spray for snails/slugs can help eliminate both
of the mollusk and iron problem.  Clay soils left to their own
will also tend to be clorotic due to iron being locked onto the
clay particles.  The technique being described here helps
prevent this phenomenon.

The point here is to create a statified soil structure (the
'lazagna' effect) that is rich in soil life.  This microbial
world is a natural system that benefits the plants growing in the
soil.  Merely amending soil, applying fertilizers, etc. does not
create this effect.  It takes time to create it but it takes
care of itself more and more over time (and you and your plants).
It works.  It is natural.  It is what plants have evolved to
grow in.  Not using this method means YOU have to play God and
make sure your plants always have everything they might need,
even though they need more things that scientists have been able
to figure out to date.  This is an example of using appropriate
unnatural means (our cultivation of the plants we wish to grow
on the spot we wish to grow them) to harness a natural process
to work for us.  We unnaturally provide the raw materials for the
natural process to take place.

Sean O.

Sean A. O'Hara                       sean.ohara@groupmail.com
h o r t u l u s   a p t u s          710 Jean Street
'a garden suited to its purpose'     Oakland, CA 94610-1459, U.S.A.
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