How To Hand Dig A Post Hole In Tough Ground

As a boy of twelve, I considered myself a reluctant expert on digging post holes. The memory is a bit faded these days, but it must have been so: One day at school in the sixth grade, we were assigned the task of writing an essay about a pet peeve. And mine was digging post holes.

This was on a rattlesnake-and-barbed wire ranch in western Montana's Granite County. Granite did abound, along with river rocks and other obstacles to shovel and bar, but fencing allows for few excuses. Cows don't care how much trouble humans may have had in sinking line posts to a depth of two feet (three feet for corner and gate posts). Quite frankly, neither does a father who has a son easily assigned to the task, or at least so it seemed. My own Dad never bothered to buy a PTO-driven auger for digging post holes until after his son had graduated from high school and left the family homestead for college.

Being such a know it all about post hole digging, then, I was fairly certain there could not be much else to learn. Thus, when Pam (my wife) and I recently moved to her old stomping grounds in southern Arizona and she warned me about caliche, I was really only listening with half an ear at best. That stuff, she swore up and down, was not ordinary dirt and, lacking explosives or diamond tipped power drill bits, could only be penetrated by repeatedly soaking it with water and exercising extreme patience.

Naturally, I preferred to focus on the often stunning desert landscape.

At first it looked like no big deal. After all, our first necessary post hole was dug by the same backhoe operator who ran the water line from the shared well to our property line.

In the end, though, it seemed the right time to dig four three-foot holes in a six-foot-square pattern to house the skeleton of what will eventually serve as both a tall platform for a 500 gallon water storage tank and a roomy shower room directly below said tank. The first shovel full of dirt came up easily...and that was it. At a depth of a mere eight inches, the clay was cemented firmly together.

Pam loves Wal-Mart and informed me that her technique in the past had been to run a garden hose purchased from her favorite store into a hole for hours on end, turn the water off just before going to bed, then tackle the digging again in the morning. Unwilling to go that far, and also lacking running water, I modified her technique, using a five gallon jug of water...but as she knew, water was indeed an essential factor in the "caliche equation".

My old set of Montana digging tools, updated to accommodate Arizona caliche, now numbered a total of four items:

1. A standard Number Two shovel.

2. A long crowbar with a broad tip known as a spud bar.

3. A clamshell post hole digger. Fiskars has a better design, but the old style digger was what we had on hand.

4. A five gallon plastic bottle of water, refilled several times as needed.

Even this early in the season (late May), this part of Arizona near the Mexican border is toasty warm on most days.  Penetrating the caliche, though, required more time than toil.  Water was added, never more than about a gallon per hole at a time--nothing like Pam's long running garden hose--but the average "soak down" time ran between one and two hours for each application. 

 When to scoop the next batch of dirt from the post hole is actually not a critcal piece of timing; it's really pretty forgiving.  It could be started with a bit of water still showing, or it could wait for a number of hours--the freshly soaked soil takes a while to return to its bone dry cement like consistency.  For my comfort zone, I usually went off and did something else, checking back occasionally until only mud showed at the bottom of the hole, and then went to work.

How the person doing the digging chooses to remove the soil may well be a matter of personal preference from this point downward. My own technique involves, first, using the spud bar. The bar is slammed down with the flat, broad end scraping at an angle against the sides of the hole, which helps the sides of the hole stay nice and vertical.

After each slam-down stroke, the top of the bar is used to lever the soil (using the upper side of the hole as the fulcrum)...thus loosening the soil and making a nice pile in the center of the hole which is ready for scooping.

 Clamshell post hole diggers tend to be almost fragile due to the small bolts that serve as their pivot point fulcrums.  They are not made to withstand the rigors of prying up significant boulders like the spud bar, or even (to a lesser degree) the number two shovel.  But when used the way they were designed to be used, they perform extraordinarily well.  Give them a nice pile of loose dirt at the bottom of a hole, and they definitely Git 'R' Done.  On the other hand, three feet is about as deep as they will dig unless you make a really wide hole--because the handles have to spread out for the clamshell to close (see photo below).

When the easily scooped dirt has been removed from the hole with the clamshell, a second application of the spud bar may well produce as nice a pile (and as much additional hole depth) as the first try accomplished. But when the spud bar is clearly once again hitting nothing but hardpan, hey, time to pour some more water down the hole and go play a few games of computer solitaire. Or something.

Eventually, our four post holes reached their allotted depth of 36 inches (one at a time, of course), and the diggin' was done. This part of the project was actually spread over a span of three days, which allowed plenty of time for the water soaking part, but it could have easily enough been accomplished in two days or possibly even one day. That might have been better, as the tiny blister (see bottom photo) produced by my failure to locate my good leather work gloves could have (maybe) been large enough to get a hint of sympathy from my wife.

It's not that my Pammie lacks sympathy. It's that she likes showers. So, it's good that the holes are dug, but now (she'd like to know), when am I going to come up with the posts to stick in those holes...and the siding...and bracing...and platform lumber for the water tank...and the tank...and....

Okay, sweetheart. I got the point. Will get right on it.

Thanks for reading,

Ghost32