Using an Auger in Rocky Soil

Do Augers Work in Rocky Soil?

The fact is that most soil will have rocks in it.  Can you use an auger in rocky soil?  Will an auger work in rocky soil? Of course. That doesn’t mean you can’t drill a hole.  It just means you will need to use some extra tools when using an auger in rocky soil.  It will take more time to do it by yourself than if you were using a 2 person auger.  

What is the Best Post Hole Digger for Rocky Soil? 

The best type of post hole digger to use in rocky ground is going to have a ton of torque.  Gas and propane powered augers are known for having the most power.

2 person augers are also packed with a ton of power to handle tough soil situations like rocks and roots.   

Another kind of auger to use is a 3 point post auger that you attach to a tractor or backhoe.

Augers in Rocky Soil: Before Your Dig 

Make sure you know before digging about any utility lines on your property.  Also, you should know what type of soil you’re dealing with.  Is it all rocky?  What about tons of roots?  Is it topsoil for a foot or two and then solid bedrock?   

And, this advice is gold: get a new tetanus shot before playing around in the dirt.  They need to be renewed every 10 years or so, check with your doctor.  

Knowing these essentials before digging will steer your project in the right direction and keep you safe. 

Using an Auger in Rocky Soil: Tools for Digging in Rocky Soil 

Once you’ve got the all clear to go ahead and drill, digging with an auger in rocky soil requires a few extra tools on hand to help you deal with when your auger is hitting rocks (or roots).  The best way to dig through rocky ground is to be prepared with some tools.

How do you get through rocky soil? Here is our short list of supplies you’ll need to have so you can handle any rocks or roots that come across your path.  Full details of these tools below can be found in our tools for digging hard ground post.

• Digging bar 
• Shovel and/or clam shell digger 
• Wheelbarrow 
• Root Slayer Shovel
• Picks
• Jack hammer
• Spade
• Trenching Spade

Digging Bar 

A digging bar is an essential tool here.  When you are drilling a post hole in rocky ground and you get to the rocky part, you use the bar to loosen and pry the rocks from the ground. 

Shovel and/or Clam Shell Digger 

Taking your shovel or clamshell digger, remove the extra soil from the hole.  Take your digging bar and stab and pry at the hard ground and rocks to loosen them.   Your shovel and/or clam shell digger is used to remove extra soil and rocks from your post hole. 

Wheelbarrow 

Use your wheelbarrow to store and cart away extra dirt and any post hole rock you remove.  I save any extra soil and rock for later: it might have a use down the road. 

Root Slayer Shovel

A Root Slayer Shovel is a shovel, but it’s modified with a point blade and sharp edges on the side to really dig into the soil and break up roots.

Picks

Picks (otherwise known as mattocks) are manually operated and you can use elbow grease to dig in hard ground. Digging in any sort of ground with a pick is going to be super hard work.

I would use one to start a hole, or maybe if the going gets really tough. But I have no plans to dig an entire hole with a pick.

Jackhammer 

Using a jack hammer to break up hard ground can save wear and tear on your body and save a ton of time.

Spade

Using a spade is almost like using a shovel, but its designed to slice through thick turf and soil for digging.

Trenching Spade

Trenching Spades are especially effective at digging post holes in rough soils due to the V angled head.

How Do You Dig Holes in Rocky Soil 

Using an auger in rocky soil means a lot of starting, stopping and removing rocks from each hole as you drill.  Digging post holes in rocky ground is not the best situation to be working in, but it might be your only choice. 

How do you dig holes in rocky ground? Follow our directions below to dig holes and footings in rocky soil and remove post hole rock. 

Using an Auger in Rocky Soil: How to Break Up Rock in a Post Hole 

Once you’ve started drilling, how do you know if you’ve hit a rock?  You know you’ve hit a rock if your auger stop rotating and/or starts bogging down and slowing while drilling.  Use your reverse function or pull your auger out of the hole and turn it off.  Dig out any loose dirt that is in your hole.  

Look into your hole and check for rocks.  If they are stuck in the soil, use your digging bar to loosen them up.  Grab them out with your clam shell digger, shovel or hands and put it in your wheelbarrow.   

Loosen all the soil at the bottom of your hole to make sure you’ve gotten all the rocks.  Another way is to flood the hole with water to loosen up any rocks that are in your way, let the water soak up and then pry out the rocks with a digging bar.  

Place your auger back in the hole and start drilling again.  Repeat this process with each rock you hit until you’ve drilled your hole as deep as you want. 

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How to Get a Big Rock out of a Post Hole 

Rocks are heavy.  Not only that, you might hit a rock that is larger than the post hole you are trying to drill.  What then?  You might need to bring out the big guns here and use a gas powered jack hammer to break up the large rock that’s in your way. 

Other methods include heating up the rock and then dropping very cold water onto it to split it, and hammering a few holes into the rock and using a tapered punch and a hammer to split the rock.  

If it’s just not possible to get that rock out of your way, you may have to anchor your structure to it somehow.  Check with your local codes and see what methods are allowed in your area. 

Will an Earth Auger go Through Rock

Earth augers will tackle smaller rocks and roots, depending on the auger. Some are more powerful, like those with gas engines or two man augers. They are built to deal with less than ideal soil conditions, mostly because of their increased torque, bit design, and RPMs compared to their lesser powered competitors. We review some of the best augers for rocky soil in our Best Post Hole Augers and Two Man augers posts.

Using an Auger in Rocky Soil and Your Fence Posts

If you have a ton of rock and difficult soil conditions, you may have to find an alternative to installing fence posts the traditional way. You may have to use steel rod anchors or rock cages above ground to securely anchor your posts.

Conclusion

Using an auger in rocky soil can be done.  There will be a few extra steps to getting that post hole dug in rocky ground, but following the tips above, you’ll get it done without issue.

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