Post Hole Digger vs Auger vs Digging Bar: The Right Tool for Your Soil and Hole Count
Digging a single post hole is a chore. Digging twenty for a fence line is a project, and the wrong tool can turn a weekend into a week. The good news is that the choice comes down to two questions: what's in your soil, and how many holes do you need?
This guide compares the four tools most homeowners choose between, explains why rocky and clay soils change the answer, and covers the safety step that comes before any of them.
- Call 811 (in the US) before you dig, every time. Utility lines can be shallower than you think.
- Clamshell post hole digger: the default for a handful of holes in average soil.
- Hand auger: good in soft, stone-free soil; struggles with rocks and roots.
- Digging bar: the essential partner tool for rocky or compacted soil. Most people who dig more than a few holes end up owning one.
- Power auger: worth renting for long fence lines in reasonably cooperative soil. Treat its torque with respect.
Before you dig: the step that isn't optional
In the United States, 811 is the national call-before-you-dig number. You contact it a few days before digging, and member utilities send someone to mark the approximate location of underground lines in your work area. It's free to the homeowner. Other countries have their own one-call services. Utility lines aren't always buried as deep as people assume, and a post hole is exactly the kind of narrow, deep excavation that finds them.
Also check property lines, any HOA or permit requirements for fences, and private lines that utilities won't mark, such as irrigation, landscape lighting, propane lines or a run to a detached garage.
The four tools at a glance
| Tool | Best soil | Best hole count | Strengths | Weaknesses |
|---|---|---|---|---|
| Clamshell digger | Most soils, moderate rocks | A few to a dozen or so | Simple, affordable, lifts soil out cleanly | Tiring; hard in rocky or very dry clay |
| Hand auger | Soft loam, sand, stone-free | A few | Neat round holes, little disturbance | Stops at rocks and roots; slow in clay |
| Digging bar | Rocky, compacted, rooty | Any (as a helper) | Breaks hardpan, pries rocks, cuts roots | Doesn't remove soil on its own |
| Power auger | Loam, clay without large rocks | Many | Fast on long runs | Kickback risk; rocks and roots can stop it hard |
Clamshell post hole digger
Two long handles hinge to a pair of curved blades. You drive the open blades into the ground, spread the handles to close the blades around the soil, and lift it out. It's the standard tool because it works acceptably in most soils and doesn't need power.
What to look for
- Handle material: fiberglass and wood are common. Fiberglass resists rot; wood can be replaced. Steel handles are strong but heavy.
- Offset handles: some designs angle the handles so your knuckles don't hit each other at the bottom of a deep hole.
- Blade construction: thicker steel blades resist bending when you hit rocks. Sharpened edges cut roots better.
- Handle length: longer handles reach deeper and add leverage. Match it to your planned hole depth.
Hand auger
A hand auger is a T-handle with a cutting bit at the bottom. You twist it into the ground and lift it out periodically to empty the soil. In soft, stone-free soil it's satisfying and neat. In rocky or rooty ground, it stops dead. Hand augers suit planting holes, small posts and soil sampling more than fence lines in difficult ground.
Digging bar: the tool that makes the others work
A digging bar is a long, heavy steel bar, usually with a chisel or wedge point on one end and a flat tamping head on the other. It doesn't lift soil out. What it does is break up compacted layers, pry rocks loose, chop through roots and, with the tamping end, compact backfill around a post.
If you've ever stopped digging because the clamshell bounces off something, the bar is the answer. Loosen a few inches with the bar, remove that soil with the digger, repeat. Heavier bars hit harder and do more of the work for you, but they're tiring to lift. Choose one you can handle safely.
Power auger
Power augers come in one-person, two-person and towable or tractor-mounted versions, powered by gas engines or batteries. They're fast in cooperative soil and turn a long fence line into a manageable job. They're also the tool most likely to hurt you. When a spinning bit catches a root or rock, the torque has to go somewhere, and that can be into your arms and back.
- Rent before buying. Unless you dig many holes every year, renting a power auger is usually more sensible than owning one.
- Two-person models spread the kickback between two people and are often recommended for larger bits.
- Towable and hydraulic augers from rental shops absorb torque through a frame rather than your body, which is a meaningful safety improvement for many holes.
- Bit size should match your post and footing plan. Rental shops can advise.
Choosing by soil type
Sandy or loamy, few rocks
Clamshell or hand auger for a few holes; power auger for many.
Clay
Clamshell plus a digging bar. Slightly moist clay is easier than bone-dry or saturated clay. Power augers can work but may bind.
Rocky or with roots
Digging bar first, clamshell second. Power augers often fight you here; a towable unit may cope better.
How deep is deep enough?
Post depth depends on post height, the load (gate, fence, deck), wind exposure and your local frost depth. A frequently cited rule of thumb for fence posts is to bury roughly a third of the post's total length, but local building codes and the fence or deck manufacturer's instructions should decide. Structural posts for decks and similar projects are governed by local code, and many areas require footings to extend below the frost line. Check with your local building department.
Mistakes that slow the job down
- Digging dry, hard clay. Many diggers find clay easier to work after it's been moistened, not when it's baked or flooded. Pre-wetting a hole and waiting can help.
- Bell-shaped holes. A clamshell tends to widen the top of the hole as you work. Keep the handles as vertical as you can and use the bar to square the sides.
- Piling spoil right at the edge. Loose soil falls back in. Drop it on a tarp a step away so cleanup and backfill are easier.
- Forcing the tool. When a digger or auger stops hard, find out why. It may be a rock, a root, or something that shouldn't be there.
Post hole project checklist
- 811 request made and marks in place
- Property lines and any permit or HOA rules confirmed
- Private underground lines located
- Clamshell digger and digging bar on hand
- Power auger rented, if needed, with operating briefing
- Gloves, eye protection and sturdy boots
- Gravel and concrete or backfill plan, per your fence instructions
- A level and string line for alignment
FAQ
Is a post hole digger or an auger better?
For a few holes in average soil, a clamshell post hole digger is simple and reliable. For many holes in cooperative soil, a power auger is much faster. In rocky ground, a digging bar plus clamshell often beats an auger.
How do you dig a post hole in rocky soil?
Break up the soil and pry out rocks with a digging bar, then remove the loosened material with a clamshell digger. Repeat in layers. Large rocks may need to be worked loose from the side of the hole.
Should I rent or buy a power auger?
Most homeowners are better off renting. Rental shops can match the bit to your post size, show you how to operate it, and offer towable units that handle torque more safely.
Do I really need to call 811 for a fence?
Yes. In the US, calling 811 before any digging is the standard recommendation and is required in many states. Fence post holes are a common way people strike buried lines.
Bottom line
For most homeowners, a clamshell post hole digger plus a digging bar handles nearly any small fence or garden project. Rent a power auger, ideally a towable one, for long runs. And make the 811 call first, every time.
For more practical tool guides, visit the Garden Gear blog.