What type of soil is this? Oh, and Hi!

Ok so Rachio 3 is on it’s way, yay! New here so be gentle. I tried doing the jar test and I’m a bit confused as it seems to me that I only have 2 layers instead of 3. I let it sit about 16 hours and it looks like this. We’ve always assumed it was some type of clay as its slimy when wet and hard as a rock when dry. I’m in Southern NM if that helps and I found an article suggesting that my area has fine sandy loam. Does this jar concur with that?

@wafflesngravy - check out this post for a USDA website that may have your soil type info ->


I think i got it figured out. Thank you!

From this end of the ‘net looks like all silt to mud sized particles with a some organics. Not much, if any, sand. Maybe silt-clay range on the soil texture triangle. But that NRCS web soil survey as suggested in prior post may be the best way to go. Bonus if the results match your seeming lack of sand.


The more I read the more confuse I get lol. That site says I have loam. My jar doesnt look like loam. I also found a county assessment done years ago that says I have fine sandy loam.

Maybe I did the jar wrong? I just took some top soil inch or 2 from an area that had nothing growing on it. Should I have gone deeper? IDK. I have a feeling I wont even use that part of the Rachio anyways. I’m on an un-metered well so really have no reason to conserve water and I already know how many minutes make up a good lawn. We’ll see when it gets here and I start playing.

soil inventories are done at a rather small map scale so they tend to fail at capturing local large map scale variability. It also doesn’t help that properties can be manipulated such as top soil removal by grading, among other things. Then there’s soil variation at different depths. So It’s all a best guess using various DIY methods like the jar and soil ribbon test (does it feel coarsely gritty when wet? May have some sand)short of doing a meticulous soil sample and bringing to your university ag extension. But to add more complexity, can try the soil ribbon test! :wink:

There’s a reason soil scientists are very specialized in education and quite important. I’m a geologist and I’ll never pretend to understand soil.


Doesn’t feel gritty at all. When wet its very slimy and smooth. It sticks to everything. When dry its hard as a rock and you can’t even dig through it. I’ve read this describes clay. It was farmland when I bought the property. They used to grow alphalpha and cotton here. I know the land was leveled for that, but whether or not they brought anything in I have no idea, but I doubt it. They also had cows and horses grazing it for several years before I bought it.

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Sure sounds like clay or very close to it at the depth you’ve sampled. Clay to silty clay, since no sand means loam is likely out of the picture. You may experiment and see how things go with clay and then silty clay. Assuming you want to since if you really have no need to conserve (for long term sustainability of groundwater) then go with what you know works.

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Here’s a seemingly nice resource on soil texture:

Someone more knowledgeable correct me if I’m wrong, but I think soil type controls just two parameters, one less important - percolation rate, one very important - soil carrying capacity.

For percolation rates, start with a guess, and if you get puddling, shift the soil type towards clay, and you’ll get longer “cycle soak” gaps for the water to soak in.

For soil carrying capacity, just fill your jar again with dry soil, packed as it is in your property, and then measure how much water you can add (slowly) before it overflows. If the jar is 24oz, and you can add 2.4oz, then set under advanced: “Available Water” = 0.1 (2.4/24). The best way to do this is to weigh the jar full of dry soil, then soak it for a while to get it completely saturated and weigh it again. The difference is the water you’ve added.

I’m my yard, the soil appears to be Clay Loam, for which Rachio seems to set a default Available Water of 0.17, but my measurements give Available Water more like 0.1, which as others have noted, changes the behavior dramatically.