Clay Soils
John Darlington
I till gardens every Spring for other gardeners (19 years now), as many as
50 in some seasons. About 2/3 of these are on heavy clay soil. In my experi-
ence, the best thing you can do is add peatmoss, with some compost. Peatmoss
is also the most expensive thing you can add to a garden.(Just say-even if you
live in Canada, peat moss ain't cheap). I usually tell my customers that peat
moss is the best thing to add to their garden, if money is not a concern.
So, what do I recommend if money IS a concern? Sand! That's right, sand; & the
coarser the better-builders sand if you can get it.
Why? Well, you have to look at clay particles under a microscope to find out.
(No, I don't know what power). Clay particles,(I've also heard them referred
to as platelets) are like sheets of paper, flat & smooth. Coarse sand is
shaped like balls or rocks or stones and when the two are mixed together(as
with my handy dandy Troy-Bilt rototiller) the shapes of the sand particles
gets in between the flat, paper-like clay particles and forces/keeps them
apart and allows for much better air and water circulation.(read-fluffier
soil, better drainage, less compaction, less standing water after a rainstorm
or watering).
This is based on my experiences in Eastern Ontario and Western Quebec in
gardens tended by different people of different skill levels and it seems to
work. I still recommend that they compost & even add a little peat moss (just
not enough to break the bank).
How long does it take? How much sand should you add? Very hard questions to
answer. I recommend to my customers that they start off adding a 1" layer over
the entire garden and work it into the top 6-8", or spread it just before I
get there & I will do the mixing with my tiller. I then check it before I do
it the following year & if it needs more, I have them do the same thing. They
can also do the mixing as they are planting if they so desire. Two applications
does wonders. YMMV.
Hope this helps. E-mail at the above address is preferred if anyone has further
questions as I don't get into this news group on as regular a basis as I would
like :^(
Regards,
JD
Robert Klebba
that organisms in the soil will consume it and pull it down below the surface.
So you need to add compost every year. But if you do add it every year, you
will see the soil structure improve in about 2 or 4 years, even if you do not
till.
Adding sand does not make sense to me. It seems that the fine clay particles
will just fill all the voids around the coarse sand particles, creating a
better structured "cement." Also too much soil mixing will assist this
soil packing, by making the sand-clay mixture homogenous.
I'm a big fan of no-till cultivation. For seeds, I add compost then plant.
For plugs or potted plants, I plant then add compost as a mulch. As the
compost is consumed during the season, I try to add more or I add mulch.
Remember clay is not necessarily infertile. It probably does have bad
drainage though. You can remedy the drainage issue by making raised beds.
Too many people approach non-ideal soil with the attitude that it has to be
corrected in one season. I have been reasonably successful working with my
patch of clay over time. After 6 years, most of my beds have good tilth, with
a minimum of tilling, and no amendments other than compost.
Bob Klebba, Madison WI
In article <DoF5B...@freenet.carleton.ca> af...@FreeNet.Carleton.CA (John
Darlington) writes:>From: af...@FreeNet.Carleton.CA (John Darlington)
>Subject: Re: Clay Soils
>Date: Sun, 17 Mar 1996 15:49:58 GMT
Dennis Mathiasen
>The best thing for clay soils is compost. The only problem with compost is
>that organisms in the soil will consume it and pull it down below the surface.
> So you need to add compost every year. But if you do add it every year, you
>will see the soil structure improve in about 2 or 4 years, even if you do not
>till.
>Adding sand does not make sense to me. It seems that the fine clay particles
>will just fill all the voids around the coarse sand particles, creating a
>better structured "cement." Also too much soil mixing will assist this
>soil packing, by making the sand-clay mixture homogenous.
Having worked with this alot I mostly agree with you, but not
completely. JD in this thread mentioned using very coarse sand. You
are right that it does fill in the voids and the sand "disappears".
The thing is this takes a few years to happen. If the sand is fine it
happens faster and cement is the result. I use alot of coarse sand -
as much as 1/3 of the soil volume. And alot of coarse compost - up to
1/2 of the soil volume. ( Both in a new bed )
The point I'm trying to make is that adding only a small percentage of
the soil volume may be why so many people have problems with this. It
takes A LOT to make a permanent difference.
The compost is far more important than the sand tho. On that we agree
completely.
DM
Robert R. Harris Stoertz
>The best thing for clay soils is compost.
Compost is good, but you need peat moss especially, to provide more
durable porosity for water and air.
:
>The compost is far more important than the sand tho. On that we agree
>completely.
>
>DM
>
bed. I will post an article about it when I get a chance. It is way
better than course builders sand, and never gets tied to the clay
particulates. I will explain in the article...
V*
Dennis Mathiasen
Now I'm getting scared. First the SKID guys and now from the other
side the famous V*.
I've read about lavasand. What you say is probably right as far as it
goes. Do you know where in the northeast I can get it for under $10
per ton? I don't need bags of stuff for soil ammendments, I need
truckloads. I suspect that most people have gardens more than 100
square feet or so. When you start comparing cost and effectiveness
the picture starts to change.
A truckload of sand here costs about $100. It's enough to make a
25x25 plot 1/3 sand to a depth of 12". Add the same amount of
compost, beat the clay up with a tiller and double digging and I've a
great start. A raised bed of nearly ideal soil. I'm lucky to have
unlimited compost free for the hauling, so if time permits, I use
more.
I doubt that $100 worth of lava sand on the same plot would have a
noticeable effect . It takes a lot of anything to make a difference
in heavy clay.
Now, don't you agree?
DM
:
>
>ani...@ix.netcom.com(:)) wrote:
>I doubt that $100 worth of lava sand on the same plot would have a
>noticeable effect . It takes a lot of anything to make a difference
>in heavy clay.
>
>Now, don't you agree?
>
>DM
>
No I dont agree! What did you think? Anyway, lava sand is not used
the same way builders sand is used. Yes, it is an additive, but you
only need 40 pounds ($8.00) per 1000 square feet (which means you can
use over 10 times the recommended rate for under 100 dollars) for it to
benefit the soil. I have heavy clay in Texas, and after two
applications of lava sand two years in a row, the soil is friable and
loam. Of course I also add humates (11.99 40 lbs per 1,000 feet), 1
yard of compost ($15.00 picked up) to my beds, approximately the same
area as you, I also use cotton burrs (free from a farmer friend). You
cannot get the burrs up north, but if you could! It is the organic
matter which loosens the clay, not the sand. Like it or not. Believe
it or not. Try making a bed with just sand, no compost, you will get
cement in a years time, down here anyway.
Victoria*
Robert R. Harris Stoertz
Brown clay is likely to drain reasonably well, while gray clay is
likely to be a real problem. I understand the factor that affects
drainage as much as anything is the presence of iron (which can give
brown clay its colour). Gray *sand* (with little iron) can be
surprisingly impervious to water.
Dark brown clay may not need the addition of anything at all, though
compost is always good.
Regards, Robert
Anthony Wallis
> Clay in itself is not as bad as many people think.
> Brown clay is likely to drain reasonably well, while gray clay is
> likely to be a real problem. I understand the factor that affects
> drainage as much as anything is the presence of iron (which can give
> brown clay its colour). Gray *sand* (with little iron) can be
Drainage is a vague term in this context; the word is more
accurately used in the context of drains and ditches, rather
than soil structure and composition.
The soil-science terms for the movement of water into,
vertically down, and sideways within a soil are infiltration,
percolation, and permeability. These depend on many factors
including organic matter content, water content, and
temperature, but the _dominant_ factor, (not surprisingly, since
it is completely in accord with common experience !) is the
_size_of_the_soil_particles_.
"Clay", "silt", "sand" (and "gravel" is you want to
extropolate beyond conventional soils) are terms describing
ranges of particle sizes. The (U.S.) scientific definition is
clay: < .002 mm
silt: .002 - .05 mm
sand: .05 - 1.00 mm
gravel: > 1.00 mm
In short, water runs into (and through) sand (with particles .05 - 1.00 mm)
much faster than it does with clay (with particles <.002 mm).
The idea of water infiltration/percolation/permeability being in any
significant way dependent on iron content of the particles is strange.
Can you back that claim up with a reference or two ?
--
to...@nexus.yorku.ca = Tony Wallis, York University, North York, Canada.
:
takes us back to soil health. Soil needs air. If clay particles are
held to eachother as tightly as they are, there is no room for air.
The compost or other additives gives clay or heavy soils some room for
air space. Percolation depends on soil tension and air. Some shallow
clay soils are laying only one foot on top of bedrock. Most likely it
is limestone, causing the clay have a high pH. If soil pH is
unbalanced or out of neutral range, there will be elements of toxic
nature available to the root hairs which can, by the way, uptake whole
molecules as done in a study by Bargyla Rateaver...Look her up, she is
in Who's Who and has written a garden primer in organics. OY, whole
molecules! Will the whole garden newsgroup now self-destruct!
ROBERT POGSON
RR> kle...@nicolet.com (Robert Klebba) wrote:
RR>
RR> >The best thing for clay soils is compost.
RR>
RR> Compost is good, but you need peat moss especially, to provide more
RR> durable porosity for water and air.
RR>
I heat with wood and have a pile of sawdust available every spring. It
takes time to decay, adds nutrients, breaks up lumps,
feeds desirable microbes, and is cheap. Some wood working plants will
actually PAY to have sawdust hauled away, so you may be able to get a
load for free. Check that they work in real wood not that glued together
stuff. Who knows what's in the glue.
---
ю NFX v1.3 [000] Exercise, eat right, stay fit, die anyway...
Stavros Macrakis
> Brown clay is likely to drain reasonably well, while gray clay is
> likely to be a real problem. I understand the factor that affects
> drainage as much as anything is the presence of iron....
In article <4j48ep$q...@sunburst.ccs.yorku.ca> to...@nexus.yorku.ca (Anthony Wallis) writes:
Drainage is a vague term in this context.... The soil-science
terms for the movement of water into, vertically down, and sideways
within a soil are infiltration, percolation, and permeability....
True, but "drainage" in a horticultural context often refers as much
to the oxygen content of the soil as its water content. The two are
of course (inversely) related in many cases.
...The idea of water...dependent on iron content of the particles
is strange....
Grey/blue clays are _symptoms_ (not causes) of poor aeration, while
brown clays are symptoms of good aeration. You get different bound
forms of iron depending on the aerobicity of the chemical environment.
-s
Jerry Roush
>RR> ÿ@FROM :rsto...@cycor.ca N
>RR> kle...@nicolet.com (Robert Klebba) wrote:
>RR>
>RR> >The best thing for clay soils is compost.
>RR>
>RR> Compost is good, but you need peat moss especially, to provide more
>RR> durable porosity for water and air.
>RR>
> I heat with wood and have a pile of sawdust available every spring. It
>takes time to decay, adds nutrients, breaks up lumps,
>feeds desirable microbes, and is cheap. Some wood working plants will
>actually PAY to have sawdust hauled away, so you may be able to get a
>load for free.
I heard that sawdust robs the soil of nitrogen, is this true? I have put it
in my compost pile, with other stuff, and it seems to be OK, but is it OK to
put it in the soil "raw"?
..jerry <><
Dennis Mathiasen
>I heard that sawdust robs the soil of nitrogen, is this true? I have put it
>in my compost pile, with other stuff, and it seems to be OK, but is it OK to
>put it in the soil "raw"?
>..jerry <><
Jerry,
Yes it will rob nitrogen, but it will give it back later in the decay
process. It's best to use it with combined with high nitrogen
materials. The process in the soil is the same as in your compost, it
just takes longer. It's a great source of cheap humus, but the payoff
will be next year not this year. Depends what shape your soil is in
to start and how much you add wether it will be a problem or not.
Common sense should be used.
DM
Doug Nelson
with a few different things:
1) sand - added to clay alone, it makes adobe, but added in addition to
the other things I list, it improves drainage and is overall pretty
cheap
2) gypsum - helps clay stay broken up once you do the hard work. It's a
white mineral available in 40lb bags for 7 to 10 dollars a bag, which
goes a long way. Adds sulfur and calcium to the soil, and helps
neutralize pH.
3) Organic Matter - several options exist: peat moss - I don't use
this, since it's expensive and it breaks down too fast. Manure - the
better, cheaper option. Wood mulch - darn near free from many cities
such as mine - its not composted yet which means these little nuggets
of wood will take several years to break down, which is good. Don't use
it alone, without manure (and some nitrogen-containing fertilizer)
because the microbes that will be breaking this stuff down over time
will tie up some of the nitrogen your plants need...
My final recipie is about half clay soil, 1/4 sand, and 1/4 organic
matter, with a handful or two of gypsum thrown in.
Oh - be sure to mulch over the top of your plantings with lots of mulch
or wood chips (I use the abovementioned mulch- it breaks down faster).
Strong sun baking on clay soil makes for a hard suface crust
impermiable to nutrients, oxygen, and water. If you have such a crust,
break it up a little before applying the mulch.
Doug Nelson