Make Your Own Soil Sampler


In quite a few of my posts, including my last one in how to water your lawn, I mentioned a soil probe sometimes called a soil sampler. It's a device used to pull a round section (core) out of your soil for examination.

It can give you a lot of information about your soil and comes in very handy if you need to see how deep your roots are, take samples to send to a lab, see how moist your soil is, etc. The design is pretty simple, just a tube with a cut out on one side. You push it down into the soil, twist it and pull it out. In the opening you can see your soil profile and grass roots. Or dump out the contents and play around with it. Mush it around, feel the texture. Whatever you need to get a good sense of your soil. Pull a few more cores, remove the thatch and grass and send it to the lab to find out even more.

The hole it leaves is very clean and hardly noticeable compared to sticking a shovel in the ground. Once you have one, you'll find you use it frequently, especially if you're having problems with your lawn.
A good soil sampler can seem a little expensive to some. Good obscure tools usually are unfortunately. The materials are likely to be chosen to both provide long life and lack and to prevent contamination of the soil and corrosion of the material.

So I started to think of how someone might easily make their own soil sampler. It's a pretty easy design but you'll need to have some tools to make one. You can pick up the materials you need at any hardware store.
Materials Needed:
  • 12-16" of 3/4" copper pipe (stainless is better but harder to find and more expensive)
  • 1 1"x1"x3/4" copper reducing T fitting
  • around 12" of 1" hardwood dowel for the handle
  • 1 1/4" bolt and nut
Step 1: Cut the copper pipe to length. Around 14" should give you a good depth but if you don't have to go very deep, if you have shallow roots for example, you can make it smaller.

Step 2: Make marks to define the cut area. Make two lines perpendicular to the pipe. One is 3/4" up from the bottom, the other about 1 1/2" - 1 3/4" down from the top. Next draw a guideline parallel with the pipe (straight up and down) connecting to two perpendicular lines. The pipe is cylindrical so it doesn't matter where on the pipe you draw it, just make it fairly straight. This will define the area of the pipe that will be removed so you can see the core.

Step 3: Make the cut. This can be a difficult cut to make and there are a number of ways to do it. Pick the tool you are comfortable using and know will work safely. Cutting metal like this isn't always easy so use your best judgment here. The safest way is to hold the piece of pipe in a bench vise and use a hack saw but it will take some time. Make sure the parallel line (the long one) is facing straight up. This will remove about 1/2 of the pipe where the cut is made. The radius for the corners doesn't really matter, just pick a radius that will work well with the tool you are using. A fatter blade needs a bigger radius.

Step 4: Attach the T fitting to the top of the pipe. If you're using copper you can solder the joint to help hold it in place. Then drill a hole wide enough to accommodate your bolt. Try and center the hole in the area where the pipe and the fitting overlap. The hole should go all the way through both sides of the soil probe. A drill press makes this easier. Once you have the hole, insert the bolt and tighten the nut.

Step 5: Insert the down into the 1" portion of the T to use as a handle.
That's it, it should be pretty easy to use. If you have the parts laying around and the tools and know how to do it, you get something decent. If not, you might be better off just buying one. I'm normally someone that likes to make things when I can, but I'm torn on weather making it yourself will be worth the effort. Click on the pick on the right to see current prices.

Because of the connection and the type of material, this one won't stand up to the same amount of use and stress that a purpose made soil probe but should hold up to occasional use in decent soil.
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3 comments:

  1. In your description "making the cut" I think you are leaving out some important part of the explanation. I can't figure out what you were talking about...is this one scoop cut make with a hacksaw, that cuts both sides of the hole at the same time. Or do you go down one side and then up the other side. How wide is the hole, are the bevels at the upper and lower edges important? Is it necessary to smooth/sand the cut edges, or is it best to leave them fresh and slightly jagged? Some detail would be really helpful.

    John

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  2. I made this using 2' of copper pipe. I cut off 4" of pipe for each side of the T handle. The 3/4" T junction is cheaper than a 1"-3/4 reducing T.

    To cut the big opening in the pipe, I used a Dremel tool with cutting wheel. Once I got the hang of it, it took 2 minutes to finish the cut. (Hacksaw and drill were taking too long!)

    Cost: $11

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    Replies
    1. How well is the copper pipe holding up? Is it strong enough to get a soil sample in tough soil without the pipe twisting?

      I tried making a soil sampler using EMT pipe, but it wasn't strong enough and twisted when I tried to force it into the ground. I'm thinking of using 3/4" or 1" galvanized pipe, but it would be harder to cut the opening than with the copper pipe. SO I hope you can give us a report on the copper pipe.

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