Viewing post #459299 by newbiemomgardener

RickCorey said:


The slugs ate three seedlings for every one that survived. Now I have fewer slugs, and more veggies!

>> I think the soil is not sandy nor hard clay, i really don't know how to describe it.

You might be lucky and have soil right in the sweet spot: the golden middle, "loam". Plenty of fine sand and silt, and enough clay that it can form "structure".

sand:
you can push your fingers right into it, wet or dry, easily.
if you try to make a snowball, it falls apart (no stickiness unless it's wet)
if you rub the soil between two fingers, it feels slightly gritty
you can pour it out of your hand in a thin stream of fine particles, like sand in an hourglass.


slightly damp loam:
once you've fluffed it up with a pitchfork, you can push fingers into it easily.
If you make a snowball, it barely holds its shape but will fall apart into small loose clods at a slight touch


clayey-soil: you can't push a finger into it,
it takes a lot of weight to push a shovel it
You can make snowballs that stick together, and hold their shape even if you poke them.
But they are not so firm that you can juggle them.

dry clay: a shovel bounces off, you need a pick or mattock. You can chip off pieces that feel like rocks.

wet clay: soft enough that you might sink a shovel into it slowly, with effort, but then it sticks so tightly that you can't easily pull it back out.
If you can get a handful of wet clay, you can knead it like modeling clay. You can juggle it and probably break a window with it. You might be able to moisten your figners and squeeze out a thin ribbon of pure clay.
- - -

Someone told me that a soil must have at least 50% sand and no more than about 27% clay in order to be called "loam".
Even 'clay loam' and 'silty clay loam' can have no more than 40% clay.

Someone else said that an "ideal" soil would have 50% "pore space", but that sounds VERY open to me.
I hope to get 20% air space if I'm lucky (gauging it by eye and by guess.)

I agree with this, but some other advice in this PDF seems to me focused too much on "landscaping" and not enough on "gardening". A soil with NO clay can't form "structure" because it has no stickiness - it is TOO friable.

"Soils with more clay content, such as the various loams, aggregate into larger chunks called peds. Highly aggregated soils are optimal for root growth and aeration, but can be easily destroyed by any activity that results in soil compaction."
http://puyallup.wsu.edu/~Linda...


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Science experiment: put an inch or so of soil into a clear jar and mostly fill the jar with water.
Shake until the soil "dissolves".
Watch closely as it settles out.

Gravel and Grit will drop "like a rock", in a second. Anything over 1-2 mm is grit. Smaller then 1 mm is sand.

sand will settle within a few seconds (⅛ mm to 1 mm)

very fine sand, like 1/16 mm or down to 0.05 mm, may take a few more seconds - - - > that shows how much sand you have


What remains in suspension for a little while is particles smaller than around 1/16th mm (around 0.0025" or 2.5 mils).

According to the USDA Soil Texture Classification system, the sand-silt boundary is 0.05 mm (50 microns or around 50 times the size of a bacterium).

Silt is supposed to pass through a #200 mesh, which I think is around 5 mils. I think silt will settle within a minute or so.

I read that silt and clay are chemically different. Clay has thin plate-shaped particles held together by electrostatic forces, so it is really sticky unless broken up by organic matter and sand.

I believe that most clay is colloidal in size - mostly smaller than silt particles, and it settles very slowly.

Thanks Rick. This is very educating for me.. i will have to do an experiment with the soil around the house.. The consistency of the soil where you can or can not stick your finger right away, this is when it isn't wet right?