Dig postholes faster and easier and position them more accurately using this step-by-step guide. It includes many labor-saving tips.
If you have more than a couple of postholes to dig, don't stop at a shovel and a clamshell digger. You'll treasure two more tools just as much. Pick up a tile spade. The long, narrow blade will get you places no other shovel can. Also get a tamper-end digging bar.
So, big shot, you think you know how to dig postholes, eh? Sure you do—anyone can dig a hole. But how hard do you want to work, and how often do the holes end up in the wrong spot and you have to start over? Here are a few tips to get perfectly placed holes—with a little less sweat on your part.
Drive stakes to mark the center of each posthole.
Push a small nail through your string line to mark post centers.
String a line marking the outside edges of the posts. Mark the post centers on the line by untwisting the string and pushing a nail through the strands. You can fine-tune the nail position just by sliding it to the exact location. Then pound stakes to mark the center of the holes. If you're using 4x4 posts, that will be just under 2 in. from the string.
Dig around the stake to center the hole.
Set the string aside so you don’t wreck it while digging. And don't just start digging away; drill yourself a pilot hole first. Carve out a round plug to outline the posthole. That'll get you started in exactly the right spot. Throw the dirt onto a tarp to protect your lawn.
A special tile shovel slices through roots and turf and gets the hole started more easily.
Unless you have very soft soil, you'll work way too hard digging with just a clamshell digger. Loosen the soil and carve away at the sides with the tile spade. It'll easily slice through small roots.
A clamshell digger removes loose soil quickly.
Plunge the open clamshell digger blades into the loosened soil and grab a load of fill.
A recip saw will reach down the hole and cut those tough roots, especially with a long blade.
Don't kill yourself chiseling out roots. Just use a recip saw with a long, coarse blade and poke it right into the soil at the ends of the root and cut it off.
Knock rocks loose with a steel bar and lift them out with the clamshell digger.
Pick out rocks from the hole sides with your digging bar. Let them fall into the hole and pluck them out with your clamshell digger.
Pack the bottom of the hole to compress any loose soil.
Use the tamper end of the digging bar to compact the soil before setting posts or pouring concrete. That prevents any settling.
Measure the post spacing again and mark the stringline.
Restring the line, pull the nails and mark the exact post edge locations on the line with a permanent marker.
If leaving the site, cover the holes for safety.
If you're walking away from the postholes for a while, cover them with plywood. It just might save a broken leg and/or keep the sides from caving in during a storm.
Position and plumb the posts carefully before backfilling or adding concrete.
Place the posts with one side brushing against the string and the edge even with your mark. Then hold the post plumb while you fill the hole. Pack the soil with the tamper end of the digging bar every foot or so.
Power augers can speed up digging in rock- and root-free soils.
Power augers require a trip to the rental store and a brawny friend. And they're worthless in clay or rocky soil. The truth is, unless you have lots of holes to dig in sand, it's often easier to dig by hand.
Lubricate the digger with water and rap it against a shovel to knock off sticky clay.
If you're digging in sticky clay soil, dip your clamshell digger in a bucket of water so the soil won't stick. Knock off clumps on the back of the shovel. Spread a tarp to keep dirt off your grass.
A small digger is usually easier to use than a large one.
Unless you're a body builder, avoid those giant, heavy-gauge, fiberglass-handled clamshell diggers. You'll just get exhausted; you're better off with a smaller, lightweight digger.
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
You'll also need a digging bar, shovel, stringline, and leather gloves
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.