Gardening: Remove Problem Stones

Facebooktwittergoogle_plusredditpinterestlinkedinmailFacebooktwittergoogle_plusredditpinterestlinkedinmail© 2013   by Raymond Alexander Kukkee

Get the Stones Out

 
A problematic rock removed from a trench

A problematic rock weighing at least a ton

Very fortunate gardeners have deep, rich soil without any pebbles, stones or boulders. The rest of us dig around in the garden and regularly run into stones, varying from marble size all the way  to hidden boulders that weigh thousands of pounds. Unless you wish to move your garden, import stone-free garden soil, or simply give up, you have to learn how to remove problem stones.  
A Collection of Garden Rocks Successfully Sidelined

A Collection of Garden Rocks Successfully Dug out and  Sidelined

 

Here's how to do it.

   Evaluate the problem. How big is YOUR rock?  It is not especially important to know which kind of rock you have discovered, but rock is heavy. Granite weighs 168 lbs for each cubic foot, sandstone is not far behind at 155lbs/cubic foot.   That is a piece of rock  only  12"x12"x12".  If your rock is about a foot long, and as wide, you can be sure it will weigh in 150 lbs or more.

Is the rock loose as it sits in the soil?  Can you move it with a pry bar even a bit?       If the rock will not move or vibrate even when struck with a heavy bar or hammer, it may be bedrock;   if so, it may be attached directly to the nearest mountain or wedged tightly between other rocks.  If it moves the tiniest bit, it may just be sitting firmly  in hard soil like clay.

Can the rock be easily broken?  Is it mudstone, sandstone, or another bedded (layered) rock that can be easily split? (Does it look like it has 'layers'?)  If so, you can remove it systematically by removing manageable pieces with  a rock chisel and heavy hammer.  Smacking it with a sledge hammer will tell you in a hurry. If it rings like a bell, it's not likely you're going to break it at all.

Two NEW garden rocks

Two NEWLY dug  garden rocks--Clearly hard on the Cultivator !

Let's hope the rock breaks or, if not, at least  moves a bit when you whack it.           It is simple to remove a problem stone of even three hundred pounds or more  by using the following technique.

For the record, this process imitates some aspects of nature. In the winter, water  in the soil around the  rocks  freezes solid.  Water expands when it freezes, pushing in all directions,  so the extreme pressure from the expansion  tends to displace the rock upwards, after many years, moving it to the surface of the soil until movement by the  freeze/thaw  cycle comes to a balance.  You can  mimic this natural process to your benefit when trying to remove problem stones. How?

Use sand or garden dirt to remove problem stones.

Instead of water and ice, we will be using sand, or garden dirt. Locate that garden nuisance, and dig a wedge-shaped hole beside the rock with a shovel. Hopefully you'll find the bottom, or an edge of the stone in the process, and the rock can be moved a little where it sits.

Use a liner bar, (typically pointed like a wedge) or other heavy steel bar,   and drive it into the soil under or beside the rock. Support the bar at the surface to achieve the necessary support which will  prevent the bar cutting down into soft dirt. Use a log, brick, or stone to support the bar. Use leverage to your advantage. Pry the rock sideways and up--as much as possible.  Have a helper quickly push as much  sand or dirt into the hole around the rock as possible. Dry sand is beneficial because it pours and slides. Fill all of the space you have created.

Now you can relax;  did you notice how the rock sits higher? It cannot settle right back down into the hole, because you have already filled that space--hopefully under the rock.

Repeat the same process three or four times, and the rock will be loosened and extracted from the deepest part of the original hole. Make sure you add as much sand or dirt as possible each time you pry the rock up, even adding small stones to the cavity as necessary. The object is to fill in the hole, so it is impossible for  the rock to settle back down into position.   Easy isn't it?

When your new pet rock is raised enough and the bottom of the rock is reasonably close  to the surface, simply roll the rock out by hand if it is not too heavy or too slippery. For large boulders, it can be helpful to dig out an appropriately shaped, ramp in the side of the hole to make it easier to roll the stone up onto level ground.  Get help if necessary, a boulder rolling back into a hole can break your leg.   Be sure to  wedge the rock  it if necessary and fill in behind it to ensure it doesn't  roll back in the hole.   When the rock is out of the hole completely, fill in the hole completely with garden soil or sand.

Roll the beast off of the garden with pry bars,  --or use a machine to move it if necessary.  Work carefully, rock is very heavy!  Don't even try to lift it unless it's small enough to do so. If you do lift it, lift correctly to avoid back injury.

Use the same technique for gigantic boulders that are 'submerged' in the soil.  If they are over a thousand pounds, get a machine and a qualified operator to do the digging and prying, but use the same basic technique, why do it the hard way and bust a hydraulic hose?

 

Other techniques to remove problem stones

Some boulders are so firmly embedded in the soil, or so large they cannot be easily moved without excavating around them.

Very large boulder firmly embedded.  It has to go!

Another very large boulder firmly embedded. It has to go one way or the other!

 

  • For  large boulders, drill a line of holes in the rock, follow the layers if possible,  and split the boulder with feather wedges, which are a specially designed rod with two wedge-shaped attachments.
  • Blasting with explosives:  Blasting is not permitted in urban environments unless performed by specially trained individuals using blasting mats and special safety protocol.  Permits are now required to obtain any explosive materials or supplies.
  • Pour special slow-expanding proprietary liquid mixes into holes, plug the holes securely and wait.   The rock will split as the compound expands.
  • Drill a series of holes in the rock, fill them with water, plug the hole tightly with a wooden plug, and let nature take it's course; nature can also freeze  and split the rock.
  • Rent a portable rock saw with a suitable diamond blade and saw pieces off systematically.
  • Softer rocks like sandstone may be  easily split  along fracture lines and removed piece by piece.
  • Hire a mechanical backhoe to dig the biggest rocks out or rent jackhammers. Note that If the rock is too hard,  jackhammers may be completely  ineffective.

There you have it; the easy way to remove problem stones from your garden -and a few extra options if you are faced with large boulders. Maybe you'll find gold nugget or diamond while you get the stones out of your garden, lawn-- or even the back forty.

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   Is that Incoming I hear?

Tags: #gardening #home&garden, #garden problems, #stone removal

Photographs  © by rakukkee  all rights reserved +    Facebooktwittergoogle_plusredditpinterestlinkedinmailFacebooktwittergoogle_plusredditpinterestlinkedinmail

2 Responses to Gardening: Remove Problem Stones

  1. So much helpful advice here, Raymond! The problem is one that readers will no longer have once they get to the end of the post. Well written too, that is the part I (no green thumb) appreciate most 🙂

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