# Sampling rocky soil



## TravisT (Oct 20, 2019)

Quick question - my soil is so rocky, it has been impossible for me to get a 4" soil sample with my soil probe. I can get about 2" max before I start hitting clay and gravel.

Should I only prove this deep, is is there another way to get a good sample in these conditions?


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## g-man (Jun 15, 2017)

Use a shovel. But if it is so much rock, it is will hard to grow anything.


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## TravisT (Oct 20, 2019)

g-man said:


> Use a shovel. But if it is so much rock, it is will hard to grow anything.


Tell me about it! While the best way is probably to strip everything out and bring in good soil, unfortunately it's just not practical. I've brought in a bunch of soil (probably ~20 yards) so far and I'm trying to build up as much "good" soil as possible through leveling and top dressing. In the meantime, I'm also trying to supplement the existing soil to improve growth.

The other problem is that my property is very hilly and sloped - nothing crazy, but there are almost no flat areas on my property because of how everything was graded. I can only add so much before hardscapes (sidewalks, driveways, etc.) are the limiting factor.

My question is, if the rock will limit the growth down, does it even matter what the soil composition is in the rocky layer? Should I only sample the top 2" and continue to add to it through topdressing/leveling?


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## g-man (Jun 15, 2017)

Maybe take a picture of the rock layer. In my experience, you need at least 6in of soil otherwise the rocks get hot/dry in the summer and fry the roots.


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## TravisT (Oct 20, 2019)

I'll see what I can do on pictures. While I have unearthed some pretty massive rocks (natural) in my lawn, I think most of what I'm hitting is a mixture of heavy clay and smaller rocks (like paver base/crush-n-run size).


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## TravisT (Oct 20, 2019)

Here are a couple of pictures from my sampling today. Had to break out the shovel - the soil sampler was not getting past maybe an inch or two at best.





As you can see in the first picture, my first attempt hit a rock about fist sized at about 2" sub-surface. Heavy packed clay riddled with rocks is everywhere here!


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## San (Jun 21, 2021)

My yard has lots of rocks as well.

I ended up getting a ProPlugger, and used that as a soil prob, after some good rainfall.

As it's a lot larger, you can put a lot more force on it, and I only got stuck on a couple of places with really big rocks.


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## TravisT (Oct 20, 2019)

I have one of those, and have used it in the past. I envy the people that can use a soil probe and pull an 8" sample. I'm not in that camp… maybe one day!


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