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Amending Soil that is Mostly Clay

St. Phatty

Active member
I have had a chance to try growing corn, peanuts etc. in soil that is mostly clay in the form of de-composed granite.
Work in >>> Food out.
Lots of work in, very little food out.

I got some idea of the soil consistency by planting trees in the mix. When some of them die, I throw the root-balls in a pile.
When I come back to look at the root-balls, they are like concrete.

My chickens like to peck at the dirt. When they peck the root-balls, it hurts their beaks ! (OK, well, just kidding about that part.)

I have a neighbor who is normally very can-do. Everything I've ever asked him is "can do".

We were talking about amending the clay-ish soil. He said he wouldn't try. He would literally rather pay to have soil trucked in, than to amend our local soil.

That leaves me thinking -
A/ There's got to be a way, and
B/ It will require patience.

I was talking with another lady gardener who had some experience with similar clay soils.

She suggested, raised container beds <== I like that idea !

That made me think of a previous encounter with tightly packed soil, and the use of root crops to break it up. In that case we had wild radishes to work with. The lady gardener said she used beets, which grew big, 6 to 9 inches diameter.

Anyway, I was going to try a 2-pronged approach for this year -
A/ smaller quantities of imported dirt in raised containers or just plopped over the clay.
B/ LOTS of radishes (the big kind) and beets and whatever root crops make sense.
C/ maybe spread manure over it, & see what happens.


I'm still curious about the labor intensive approach - to dig up a foot deep with a roto-tiller and mix in mixers like co-co and perlite and peat.

Anybody ever tried that ?

I suspect that buried rocks would be a problem. Ever roto-tilled soil that had enough rocks to build a rock wall ?


Anyway, I don't like to have 2 acres of potential garden land and to give up and just garden 1/4 acre.
 

Mate Dave

Propagator
ICMag Donor
Veteran
Clay is the best soil to start with. It's got certain benefits once it's been tilled and you have some OM
 

aridbud

automeister
ICMag Donor
Veteran
Rototilling or turning soil repeatedly is not enough. Sand, mulch, perlite needed in layers, sawdust. more coffee grounds (I put out a collection bucket near the pot at work, some people hit their local coffee cafés up for their grounds) perlite. buckwheat hulls. rice hulls. peatmoss. triple ground mulch....

A few articles:
https://peakgardening.wordpress.com/2010/05/25/dealing-with-clay-soils-part-2/

http://www.ces.ncsu.edu/depts/agecon/WECO/documents/NCSU.amending.clay.soils.pdf

http://www.bachmans.com/Garden-Care...pageIndex=_pageIndexToken_workingWithClaySoil
 

Mate Dave

Propagator
ICMag Donor
Veteran
Ideally you need a compact tractor and some attachments. Then grow a few crops of mustard or whatever perhaps grass and turn it in 4 times in a year @ a loss..

Buy in a whole cowshed worth of muck and have it spread.. Grow green manures turn it in..

Plough, harrow roll and so on..

It will be worth it. Make drainage around the plot.

Grow crops suited to the soil type. Deep rooted ones. Don't fight it, work with it.

Get some animals to help feed the soil. Pigs taste great. Good workers too..
 

Bud Green

I dig dirt
Veteran
clay soil contains many macro and micro nutrients, but they are locked in because hard clay is difficult for roots to penetrate.

My native soil is mostly a hard, sandy, red clay, with lots of rocks.(sandstone and some limestone)...
It's hard work, but when I prepare a new hole, I sift the native soil thru a screen made of 1/2 inch hardware cloth, that fits over my wheelbarrow..
I use a block of wood to break the clay up thru the screen..
It breaks up all the hard clay and separates out the rocks.. This sifted clay now makes up a little less than 50% of my finished soil.

To 4 parts of this sifted, sandy clay soil, I mix in 1 part peat moss, 1 part perlite, 1 part topsoil, 2 parts fully composted cow manure and 1 part of my homemade compost...
These measurements do not need to be exact...
The whole purpose is to end up with something that, when all mixed up, cannot be compressed with your hand into a tight, hard ball of dirt.

I mix it all up well and put it in the hole...I have to just toss away a lot of the native clay soil, so the hole is big enough to hold my homemade mixture....

I make my holes approx. 36 to 42 inches across and about 16 to 18 inches deep, so they hold about 60 to 85 gallons of my garden soil mixture..

About 2 months before planting, I mix in cottonseed meal, bone meal, wood fire ashes, coffee grounds, crushed eggshell, a cup of diatomaceous earth, a cup of Epsom salts and many other organic debris,
which I easily find in the woods surrounding my gardens...

I am able to easily grow 1 to 2 pounders in these holes, and each year after harvest, I chop the plant but leave the root ball in the hole so it decays over the winter and adds more organic material to the soil....

Hope this helps...:dance013:
Bud G.
 

Limeygreen

Well-known member
Veteran
How much magnesium do you have in the soil? You may need to add sulfur via powdered sulphur or gypsum, it will bind with some magnesium and help leach it out. Magnesium will always bind soil particles together tightly.

How much Calcium do you have? Calcium also makes the soil friable, if you don't have enough you may end up with a tighter soil as well.

What I have been reading and been instructed was, on your soil test get the soil saturation levels, aim for 10% Mg and 70% calcium for clay soils. My guess if your potassium is also low.

If you do have high magnesium and low calcium or just high magnesium, add sulfur and work it in to help leach out the magnesium. If you need more calcium as well, not dolomite which contains more magnesium.

You can also run a ripper through your soil and chisel plow as deep as you can manage, this way you can help loosen up the soil, repeated rototilling of the soil will make it more compact as when you rototill it makes the soil more fine and will settle more to a cemet like soil again, at least chisel plows will break up hardpan if not too deep, a ripper should be able to break up a deeper hard pan.

If you're planting root crops, don't forget potatoes, they work not too bad for breaking up new soil.
 

Mikell

Dipshit Know-Nothing
ICMag Donor
Veteran
Dandelions. 2 acres of dandelions.

Kind of miffed you didn't think of me. I grow more dandelions than any other house in town.
 

barnyard

Member
I can't get past, "in soil that is mostly clay in the form of de-composed granite." de-composed granite isn't clay
 

stoned-trout

if it smells like fish
Veteran
sounds like my back yard.......it comes out in bricks and sticks to shovel when wet and you have to pry it off...I trucked in soil.....yeehaw..I should start making pottery
 

St. Phatty

Active member
I can't get past, "in soil that is mostly clay in the form of de-composed granite." de-composed granite isn't clay

my neighbor calls it de-composed granite.

it has the characteristic of clay of drying REALLY HARD.

grain size is small, smaller than sand.
 

corky1968

Active member
Veteran
Add lots of organic matter and turn it under.

A place I lived at about 20 years ago had lot of clay. So in the Fall, I volunteered to picked up
all the leaves that fell off the local trees and added them to a large garden hole I made in the
clay. I finished up by covering the leaves with 4 inches of dark loam.

The next year, I had a nice garden and people were surprised.

I told my neighbors that leaves normally fall and compost to a tiny layer of good soil.
So I explained to them that a 2 foot layer of leaves in the fall is much better than a
tiny layer.

A 4 to 6-inch layer of composting straw also works great. Done that before.
 
compost, compost and more compost.
Grow "fertilizer-crops" you can turn under.
Mix wood chips with your clay-soil. Takes several 3-4 years to break down. After that you can grow.
 

St. Phatty

Active member
I planted a few hundred -

radishes
carrots (the humongous kind)
jicama
turnips
potatoes
onions

and basically all the root crops I could find.

Basically it creates a slow motion process for introducing organic matter into the soil.


I also started manually roto-tilling the area. Basically, digging up a strip 2 feet wide and about 25 feet long, and filling it with leaves. Then raking the dirt back on top.

Far from perfect, but WAY more mixing than what I started with.


In soil science, particle size is pretty important.

When I started, particle size was pretty much infinite - a plane of de-composed granite extending in all directions, with 1 to 6 inches of de-composed oak leaves on top.

Actually some real good humus, but very little natural mixing of organic matter into the heavier sand/clay/ de-composed granite.
 

caljim

I'm on the edge. Of what I'm not sure.
Veteran
Like many others have said...Cover crops tilled back into the eath to create better tilth and more organic matter in the soil.

Deep rooting crops like dicon raddish to break up the soil deep down in bring nutients up.

Legumes to fix nitrogen in the soil.

Wheat or rye grasses and oats to provide, literally, tons of biomass.

Turn it all in and repeat. Your knocking down the weed seed population and creating great soil at the same time.
 

westtexas

Member
personal formula

personal formula

We always mixed humus and vegetable compost with sand and wheat straw and till the into the ground about 12 to 18" deep..
 
Add lots of organic matter and turn it under.

A place I lived at about 20 years ago had lot of clay. So in the Fall, I volunteered to picked up
all the leaves that fell off the local trees and added them to a large garden hole I made in the
clay. I finished up by covering the leaves with 4 inches of dark loam.

The next year, I had a nice garden and people were surprised.

I told my neighbors that leaves normally fall and compost to a tiny layer of good soil.
So I explained to them that a 2 foot layer of leaves in the fall is much better than a
tiny layer.

A 4 to 6-inch layer of composting straw also works great. Done that before.
Good advice right there. Eventually the soil gets good. Im in a similar situation with hard clay ground. After 8 years of adding mulched up leaves plus rabbit poop from raising rabbits, my garden soil is now very loany and rich. I grow a bunch of tomatoes plus green bean, potatoes and several varieties of leaf lettuce. Havent added any other additional fertilizers in 3 or 4 years, just plant and leave them alone. Last year. We had tomato plants so big around that 2 people couldn't hold hands and reach around the tomato plants. Keep adding organic material, and eventually the soil will be good.
 

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