How to Dig Post Holes

Step 1. Measure and Mark

The first step for creating a post hole is to measure and mark where you want the post to go. Find a place that is safe and mark exactly where you want the posts will go. When you’re measuring out the hole, you should keep in mind that the hole should be twice the diameter of the post, so make sure you allow enough room between each hole for that space. A handy tip for if you’re using a post hole borer, is to make sure to mark the auger with something temporary and removable like tape or chalk to the depth you’re wanting the hole to be, so that you know where to stop. If boring holes for a fence or retaining wall and following a line, setting up a string line or guide will help keep your posts in line and vertical. 

By selecting a safe place to create the hole, you can know the exact area that the post needs to go and you won’t lose sight of it in the process of digging, which can happen very easily.

Step 2. Dig and Clear the Pilot Hole

After you’ve marked the spot, you can start digging and clearing the hole. If the ground is particularly stony or tough, you can loosen the ground with a round mouth shovel by slicing the earth at the top of the hole.  To do this you should stick the blade of the shovel vertically on the side of the hole, aiming the handle away from your body. Then you need to jump straight on the blade of the spade with two feet to cut the walls of the hole. Repeat this about 4 times to strike each side of the hole. If the ground is soft this step may not be necessary.

Step 3. Prep your Post Hole Borer

Before you operate the post hole borer, you need to make sure you have the appropriate safety equipment on to avoid any injuries, including eye protection, hearing protection, gloves and safety shoes. Pull start the post hole borer by using the cord and you’re good to go from there.

Step 4. Use your Post Borer

Once you’ve created the pilot hole, you can switch equipment to either the one man post hole borer if it’s a smaller hole or the two person post hole borer with the help of a friend to get the bulk of the hole dug up. This tool can make the job much easier than if you were to continue using the shovel as it will create flat walls in the hole and it will make it barrel shaped, which is perfect for a post hole. If you don’t own a post hole borer - don’t fret! You can easily hire post hole borers from Hirepool.

If you’re using the two person post hole borer, have each person on either side of the borer, holding the handles firmly. Let’s start digging: 

• Starting out slow, advance the throttle of the post hole borer and let the machine start digging into the hole.
  
  
  
• By thrusting the blades into the earth, they will slice into the gravel more easily. Make sure you have a tight grip of the handles with two hands at all times when operating the borer and keep steady pressure.  As you make the hole wider, you may begin to feel roots and other material in the way of the post hole borer.
  
  
  
• Just rotate the blades to cut through these and you’ll be free to dig the rest of the hole.
  
  
  
• Once you’ve reached 6 inches or so into the earth, bring the post hole borer back up and remove the dirt off the blade so that the blade is clear of any dirt and will clear the hole more easily.
  
  
  
• Place the dirt in a pile next to the dirt so that it’ll make it easier to backfill the hole later.

Step 5. Set Post in the Hole with Concrete

Once the holes have been created for each post, you can start setting the post with concrete:

• Start by pre-soaking the hole with the water so that it's drained into the soil. 
  
  
• Afterwards, you need to layer the gravel at the bottom of each hole to increase the drainage, otherwise the wood of the posts will be prone to rot and the metal may rust. 
  
  
• Set the pole in the middle of the hole on top of the gravel, ensuring the pole is vertical and posts are in line with your string guides. Use wood or clamps to support the posts and keep in place as you pour and set concrete around them. 
  
  
• A key step from here is to make sure that you’ve mixed your concrete well enough as a weakened concrete mix can cause the posts to be weak too. Make sure you have mixed your concrete perfectly and its ready to go. For projects where you’re setting multiple posts, hire a concrete mixer to speed the job up and save yourself some effort.
  
  
• Grab the round mouth shovel again and start transferring your mixed concrete into the hole, filling the hole evenly to just below ground surface, ensuring posts remain in their vertical position as the concrete sets.

Step 6. Cut Post to Height

The last step is to cut the posts to make them an even height to improve the overall appearance of the posts. While this step can be done before it’s set in the concrete, it makes more sense to do it afterwards to account for things like uneven terrain and unequal hole depths. 

To do this, you need to:

• First measure the height you want each post to be at and mark the post on each side, making sure they’re even on each side. A stringline can be used between the first post and last post to mark the height for multiple posts in between and will ensure your posts are marked at the desired height.
  
  
  
• Once that’s done, get your cutting equipment out, whether that’s a reciprocating saw, circular saw or any other cutting tool. If you’re hiring the equipment from Hirepool you can ask one of our helpful staff members for advice on which tool to use, and they’ll be able to advise you based on your situation.
  
  
  
• Line up your cutting tool with the mark you’ve made on each post and once you’re ready to start cutting, pull the trigger and let the blade run up to full speed. 
  
  
  
• Push the blade slowly through the post with both hands, using the marked line as a guide to cut cleanly through the post.
  
  
  
• To avoid any accidents, you should keep your finger away from the trigger when the saw isn’t being used so that you don’t accidentally activate the saw.