Post Setting Basics

Why do some posts lean while others last for decades?

A post resists three forces: the pull of wire or a gate hanging from it, the push of wind and animals, and the lift of freezing ground. Posts that fail early usually have too little length underground, soft backfill, or a wet hole that never drains. The post material matters less than the way the hole was dug and filled.

Before buying anything, decide what the post must do. A corner or gate post carries far more load than a line post that only holds a fence in place. Plan the strongest holes at corners, ends and gates, and treat line posts as a lighter job.

How deep should the hole be?

There is no single depth that fits every project. A common rule of thumb is that a meaningful share of the post should be underground, and that holes in cold regions should reach below the local frost depth so heaving cannot push the post upward. Gate and corner posts generally need more depth than line posts.

Ask your county extension office or the local building department what frost depth applies where you live, and whether a fence or structure post has any local requirement. For a building post, ask whether the permit office specifies footing depth and diameter.

• Dig the hole wider at the bottom than at the top when the soil allows it.
• Keep the hole walls straight and cleanly cut, not smeared or glazed.
• Add a layer of coarse gravel at the base if the site stays wet.

What should I check before I dig?

Buried lines are the biggest hazard of any digging job. In the United States you can reach the national call-before-you-dig number by dialing 811, and the service marks public utility lines for free in most places. Private lines, such as a well line, a lateral to a barn or an electric feed to a pump house, are usually not marked, so locate those from your own records or a licensed pro.

Also confirm your property line, any easement, and whether a septic field or drain lines run through the area. Walk the proposed line and mark every post location with a flag before the first hole is opened.

Should I use concrete, gravel or tamped soil?

Each backfill has a place. Tamped soil and rock in thin layers can hold a line post well in firm, well-drained ground, and it lets water drain away from the post. Concrete gives a rigid base for gate posts and heavy loads, but it can trap water against the wood if it is poured to a flat collar at the surface.

If you use concrete, slope the top away from the post so water sheds. Whatever you use, fill in lifts of a few inches and compact each one. A hole filled in one pass will settle and leave the post loose within a season or two.

• Gate and corner posts: consider concrete or deep, well-tamped backfill.
• Line posts in firm soil: tamped soil and stone often works.
• Soft or wet ground: gravel at the base improves drainage.

How do I get the post plumb and keep it there?

Set the first post, check it with a level on two adjacent faces, and brace it in both directions with stakes and scrap lumber before you backfill. Recheck plumb after every few inches of fill, because compaction can push the post out of line.

Run a string line between the end posts to keep the rest in a straight row. Let concrete cure fully before hanging a gate or stretching wire. Loading a post early is the most common way to ruin a good hole.

Which mistakes cost the most time and money?

The costly errors are predictable. Skipping the utility call, setting gate posts as shallow as line posts, using untreated wood in contact with the ground where treated or naturally durable material was needed, and tensioning a fence before the posts have settled all lead to rework.

Budget by category: posts, backfill material, hardware, tools you do not own such as an auger rental, and your time. Count the holes first, since the number of holes drives nearly every other cost.

What should I do on the day I set the post?

Set posts when the ground is workable, not frozen solid or soaked. Gather the level, string, stakes, bracing lumber, backfill material and a tamping bar before you open the first hole, and have a helper if the post is long or heavy. Rushing the setting day is how posts end up a few degrees off, and a few degrees at the base becomes a visible lean at the top.

After the work is done, walk the line and look down it from both ends. Fix small misalignments now, while the backfill is still loose. Keep a short note of the hole depth, backfill type and date, so that when a post needs attention later, you know how it was built.

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.