Saturday, April 18, 2009

Have I Got the Dirt

Pardon my weeds. I'm being soil-ly tested.

When I blogged about Tim Wheeler's free Irrigation Workshop last week (sponsored by Pasadena Water and Power), I mentioned I'd learned how to test my soil type. Some of you asked how it's done. It's called the jar test. Let's play along.

In the first photo, we put two cups of dirt into a common jar.

Well--it's kind of a nice jar, but if yours is common don't worry.

The next thing we do is fill the jar most of the way with water. Then we shake it all up. Shake it real good. Don't be shy, you gotta mix that dirt and water like it's a mud margarita.

Then leave it. Yes. Just leave it alone for a whole 24 hours. I said so, don't mess with it. Let the dirt settle. It's not an actual margarita.

What's supposedly going to happen is your dirt's going to stratify into three layers. That's what they told me, anyway. It's going to layer itself according to particle size. The biggest particles, sand, will form the bottom layer. The middle layer will be silt (medium-sized particles). On top will be your lightest particles, or clay. When you see what percentages you have of each of these soil types, you can compare your soil to a soil triangle and figure out your soil type.

What do you think? How many layers do you see? Is that sand on the bottom or silt? Is that silt on the top? Clay? What kind of soil have I got in my back yard?

22 comments:

Ted Thompson said...

The dirty kind....

Honestly, I don't see any stratification. Maybe it need to sit longer? Though I don't know how that would create a contrast between the layers (if any exist)

Very educational BTW.

Dina said...

All I know is that this sounds like the right project for my grandsons to do in my dirt.
Anyway, nice jar ya got.

USelaine said...

It looks fabulous. Like Ted, I'm not seeing strata. But then, I never learned about this stuff. I always thought the soil in the valleys down there was considered excellent quality because it has so much rich, fertile alluvial deposition. I still remember the lush, dark color, and the easy to work with texture, from my kid days playing in it. That's all I got.

Shell Sherree said...

Sorry, Petrea, I have no clue. That's what I get for going to the movies instead. I do like your chairs, though.

Shadow said...

I'm seeing a whole two layers here, dirt and...not dirt, but maybe I'm tired!

Susan C said...

Is it possible that your dirt is 100% silt?

marley said...

I can see three levels - mud at the bottom, dirty water in the middle and scum floating on the top! Lol :)

Jilly said...

Fascinating. Something I should do too although I'm sure the result would come back - no good, too chalky and sandy. It always interests me that Americans use the word dirt. Dirt to me is just that, dirt, filth, something not clean. Soil is alive, the magic substance that grows our food. I see tho you did use the word soil in your penultimate and final paragraph.

When I lived in America I got into all sorts of trouble using the wrong word...don't even ask! We all speak English but sometimes it's a different language. Vive la difference, I suppose.

Petrea said...

Jilly, I know what you mean. I caused such offense in an Oxford store when I asked the clerk for a "fanny pack." We call it English, but it's not the same language!

I think I see two strata here. At the very top (if you increase the bottom picture) you might see a teeny layer of smaller, darker particles. I just don't know which is which. Sand and silt, or silt and clay? Either way it's at least 90% of the first.

Jean Spitzer said...

This is giving me not so happy flashbacks to college chemistry lab and trying to force my experimental results into the predicted result.

altadenahiker said...

I'll tell you what -- it don't look good. Better start laying out those raised beds.

1916home.net said...

Excellent blog post. These are my fave types of blogs, where I learn something new.

I'll try this out today or tomorrow and see what I get. My dirt is strange. Its like a fine dust, I cant even call it dirt! My dirt repels water when I get it wet, so this will be quite interesting.

Once we know what our soil composition is, then what? I guess we can use the info for planting fruits and vegetables to get the right mix.

Virginia said...

All I can tell you is if I did that my entire jar would be CLAY. That is why everything in my yard struggles. This was very informative however, and i'll take it under advisement. Yikes, I've been on AH's blog too much.
V

Vanda said...

Looks like coffee grounds to me, just lighter. Chicory maybe?

maria said...

wow! your dirt is dirty...hee..heee.heee. I did this test once at a gardening class and my soil - was super acidy. there were traces of chemicles - the previous owners sprayed any chance they had rather than using a little elbow grease and a shovel.

Petrea said...

But Hiker, isn't it good if I have a lot of silt? No? It soaks up water. The weeds are very healthy.

1916, you got it. You can know from the type of soil what to grow and how to water it.

I haven't been on Karin's blog enough, V.

If it were Chickory I could use it for compost at least, right Vanda?

I haven't done a chemical test, Maria. I'm not sure how that's done but I think I can pick up something at the hardware store. I ought to do that next.

Ted Thompson said...

On the issue of linguistics, it is said that the US and UK are 2 countries separated by a common language.

Cafe Pasadena said...

They're looking for you on the set, P!!!

Christie said...

Good dark growing dirt. Looks like you can grow a lot there, but the pH would be helpful to know as well.

pasadenapio said...

Your dirt looks way better than my dirt.

J+P said...

I see two layers:

- top is fine silt of smoother, more uniform particles;

- bottom is rougher, more differentiated chunks separated by small spaces.

Thus, not a lot of variety, but some information.

(Never mind the fact that I live here and saw the layers in person.)

Miss Havisham's Tea Party said...

I am mad for science. Mud chutney!