How To Use a Post-Hole Digger

When installing a new fence or deck, you’ll likely need to dig holes for the posts. This task is much easier with a post-hole digger, which helps to create accurate and deep holes for secure installation. In the video above, This Old House landscaping contractor Roger Cook explains how to use a manual post-hole digger to create a strong foundation for your outdoor builds.

Types of Post-Hole Diggers

Post-hole diggers are specialized tools designed to create narrow, deep holes for setting posts. They come in manual and powered varieties, each with its advantages and specific uses.

Manual Post-Hole Diggers

Manual post-hole diggers are suitable for most residential use cases. They consist of two long handles connected to a pair of curved blades that close together to grab and lift soil. These tools are good for smaller jobs and allow the user to control the digging process.

Powered Post-Hole Diggers

For larger projects or harder soil, powered post-hole diggers can save time. These tools use a motor to drive an auger into the ground, quickly creating deep holes without the physical effort required by manual diggers. They’re particularly useful for professional landscapers or contractors who need to dig multiple holes quickly. They also work well for extensive fencing or deck installations.

For this guide, we’ll focus on manual post-hole diggers. Ensure the blades of your post-hole digger are sharp and designed for the soil type you’ll be working in. Narrow blades are good for digging in hard or rocky soil, while wider blades are better for soft or loamy soil. Longer handles provide better leverage, making it easier to dig deep holes with less effort.

Prepare to Dig Your Post

First, get your materials ready. In addition to your post-hole digger, you’ll need these tools:

• Bucket for removing loose soil
• Level
• Shovel
• String line
• Tape measure

Mark the Holes

Use stakes and string to outline the fence or deck perimeter to ensure straight lines and consistent spacing. Mark each post location with spray paint or a small flag. Proper marking helps avoid mistakes during digging. Double-check measurements for proper spacing between posts to maintain structural integrity.

Safety Precautions

Before you start digging, take the following precautions:

• Check for underground utilities before digging to avoid damaging pipes or cables.
• Use safety glasses to shield your eyes from flying debris.
• Wear closed-toe shoes with good traction.
• Wear sturdy work gloves to protect your hands.
• Keep children and pets away from where you’re working.

Using a Manual Post-Hole Digger

First, remove any rocks or debris where you’ll be digging to avoid damaging your tools or having objects fly up. Then, use these tips when operating the manual post-hole digger to make the process easier and more accurate.

Proper Stance and Grip

Stand with your feet shoulder-width apart, straddling the marked hole location. Grip the handles on the outside to avoid pinching your hands. Keep your back straight, and use your legs for power.

Maintaining this stance and grip reduces strain on your back and arms, allowing you to work more efficiently.

Digging Technique

The following techniques guarantee that the hole remains narrow, preventing unnecessary work and saving you time and effort:

1. Raise the digger above your head.
2. Drive the blades straight down into the soil.
3. Spread the handles apart to close the blades around the soil.
4. Lift the digger and deposit the soil on one side of the hole.
5. Repeat the process, gradually working your way deeper.

Let your body weight assist in pushing the blades into the ground, especially in hard soil. This reduces strain on your arms and shoulders.

Tips for Efficient Digging

• Start with shallow scoops and gradually go deeper as the hole forms. 
• Rotate the digger slightly between plunges to break up the soil. 
• If you hit a rock or root, turn the blades to work around the obstruction. Persistent clogs can be resolved with a digging bar.
• Keep the hole as narrow as possible to minimize unnecessary digging. Narrow holes require less concrete and provide better post stability.

Achieve the Proper Depth

As Cook mentions, a general rule is to dig to half the height of the fence above ground.

Measuring Hole Depth

Use these methods to maintain consistent depth, which is essential for structural integrity:

• Mark your desired depth on the post-hole digger handle.
• Use a tape measure to check the hole depth periodically.
• Consider using a post-hole digger with depth markings on the handles.

Adjusting for Different Soil Types

Different soil conditions may require adjustments to your digging technique:

• In sandy soil, you may need to dig deeper for stability.
• Clay soil can be challenging and may require clearing blades frequently.
• Rocky soil might require using a digging bar or powered auger.

Post Hole Finishing Touches

Once you’ve reached the desired depth, follow the below steps to finalize the project.

Clean Out the Hole

Remove any loose soil from the bottom of the hole. This creates a solid base for your post or concrete footing. You can use a trowel or small shovel for this task.

Make It Level

Use a level to make sure the sides of the hole are plumb, maintaining the vertical alignment of your posts. 

Prepare for Post Installation

If you’re setting posts in concrete, take these steps:

1. Add a thin layer of gravel at the bottom of the hole for drainage. This prevents water from pooling around the base, which can cause rot.
2. Center the post in the hole. 
3. Use temporary braces to hold the post in place while the concrete sets. Bracing prevents the post from shifting as the concrete hardens.

Tips for Concrete Setting

When working with concrete, follow these tips:

1. Mix your concrete to a thick, consistent texture. This helps it cure properly and provides a strong hold.
2. Pour concrete slowly to avoid air pockets, which can weaken the base.
3. Allow the concrete to set for at least 24 hours before attaching any fence panels or structure.