The best auger for the job depends on the scope of the task and the size of the holes you need.
An auger, aka post hole digger or earth drill, uses a spiral-shaped blade to drill holes in the earth for tasks ranging from installing a fence, deck post or telephone pole to planting bulbs, plants and trees. Several types of augers and multiple auger sizes are available. When buying or renting an auger, the tasks you’ll use it for—and the amount of muscle power you’re willing and able to put in—should dictate the type and size you choose.
Hand auger vs. power auger
Augers come in manual and powered models. Both have their own benefits and applications.
A hand auger, also called a manual auger, consists of a handle and a spiral-shaped blade. There’s no engine; all the power comes from you. These augers are used to make shallow holes without having to bend over and dig. You can take a soil sample, probe for buried materials, open a clogged drain or dig a small, relatively shallow hole for poles or bulbs with a hand auger.
On a power auger, the shank is driven by an engine, which makes drilling much easier. Engines can be powered by gas, battery or hydraulics. Gas augers are the most common and typically have more horsepower than electric augers.
For the largest jobs, consider a towable auger. These heavy-duty machines make faster work of digging holes for deck posts, fences and signs; digging through backfill or debris; and digging in uneven terrain. They’re also convenient for digging next to buildings or walls when you have limited clearance.
One-man auger vs. two-main auger
Augers come in one-man and two-man models. One-man augers are smaller and less powerful than two-man augers but also lighter and less expensive. They are used for digging small holes no wider than 8 inches.
How hard is it to use a one-man auger? Harder than you might think, especially if the soil is rocky or made of heavy clay. Even when using a one-man auger, you may want to enlist a partner to help you. If you encounter rocks, you probably won’t be able to break through with a one-man auger.
Two-man augers, designed to be operated by two people, are heavier and more powerful. You’ll need that extra power to make larger holes, drill numerous holes without excessive strain or drill through heavy or rocky soil.
Auger drill sizes
Auger drill bits come in diameters from 2 inches to 18 inches. The size of the drill bit determines the diameter of the hole.
2- to 3-inch bits: Useful for planting bulbs or installing small poles.
6-inch bit: Often used to dig holes for small plants and steel fence posts.
8- to 10-inch bit: Can be used to dig holes for larger plants or 4 x 4 wooden fence posts. Drilling a hole that’s wider than the post leaves room for adjusting the post position or adding concrete.
12+-inch bit: Ideal for making holes for deck footings and foundation piles.
How deep can an auger dig?
If you’re wondering how deep can a post hole digger dig, the answer depends on the application and the tool. Most augers dig 3 or 4 feet deep, but with some augers, an extension rod can be used to gain another 12 inches of depth. If you’re digging holes for deck footings or digging in an area where the frost depth can exceed 3 feet, you’ll need the extra depth.
Boring holes in the earth with an auger usually beats using a shovel. Choosing wisely among the different auger types and auger sizes is the key to digging the holes you need with greater speed and less sweat.