Avoid the most common post-setting mistakes before they ruin your fence
If you want a fence that stays straight for years, it starts with the posts. At Ozark Fence, we can’t count how many repairs we’ve seen that trace back to the same root issue: posts that were set too shallow, in holes that were too small, or with concrete that didn’t end up doing what the installer thought it would do.
Below is a practical, contractor-style guide to setting fence posts the right way—built around the most common mistakes we see and how to avoid them. This is especially important in Springfield, Missouri, where soil conditions can vary from loose dirt to rock and clay, and where frost and seasonal moisture changes can slowly move a fence that wasn’t installed correctly.
1) Choose the Right Post Material for Ground Contact
Any post that goes into the ground needs to be able to handle moisture long term. Most homeowners default to treated pine posts, and that’s fine—pine absolutely needs to be treated if it will touch soil.
What many people don’t realize is that there are exceptions: cedar and redwood posts can be used untreated because they have natural rot resistance, though they’re more expensive and less common.
How to avoid issues:
- Use treated pine for standard builds if budget matters
- Consider cedar for upgrades where longevity is the goal
- If using pine, accept that ground contact is still tough over time and plan accordingly
2) Dig the Hole the Correct Width (Not “Close Enough”)
A major mistake is digging holes that are too narrow. You need enough room for concrete to surround the post and create a stable footing.
You’ll often hear “two times the post width,” but the more widely accepted standard is three times the widest diameter of the post.
For a 4×4 post (which is actually 3.5 inches by 3.5 inches), many installers simply use a 12-inch auger and call it good.
Why it matters: a skinny hole doesn’t leave enough concrete around the post, which reduces stability and increases movement over time.
How to avoid issues:
- Aim for roughly 3x post width
- Err on the slightly wider side rather than narrow
- If you want the fence to last, give the concrete room to do its job
3) Dig Deep Enough for Springfield Conditions
Depth is where most fence posts fail, especially after freeze-thaw cycles and wet seasons.
Some DIY guidance suggests “one third to one half of the post height,” but post depth is highly regional. What works in one state may fail in another.
A strong standard to follow is:
- 30 inches minimum depth, and
- 6 inches deeper than your local frost depth
That’s the kind of thinking that builds a fence you don’t have to constantly re-square and re-level.
Also, Southwest Missouri soil isn’t always friendly. In many parts of the country a hand-held auger can do the job easily. Here, you may need a machine-mounted auger, especially if you hit rock or heavy clay.
The good news is rental yards commonly rent mini-skids with augers by the day.
How to avoid issues:
- Confirm frost depth for Greene County or your local area
- Treat 30 inches as a baseline, not a maximum
- Choose equipment that matches Springfield soil reality
4) If You Add Gravel, Account for It in Your Depth
Gravel is often used at the bottom of the hole for drainage, and that part makes sense: less water sitting under the post can reduce rot risk.
But here’s the mistake: installers add 3 to 6 inches of gravel and forget that it reduces the depth of concrete.
If you dig a 30-inch hole and add 6 inches of gravel, you no longer have a 30-inch footing—you have a 24-inch footing.
How to avoid issues:
- If you want 30 inches of footing and you add 6 inches of gravel, dig 36 inches total
- Decide whether you’re prioritizing drainage or footing depth, then build your hole accordingly
There’s also debate about whether gravel makes posts easier to plumb. In practice, you can plumb the post once the concrete is in and still get great results.
What matters more is that your final footing depth is correct.
5) Temporary 2×4 Bracing Is Often Unnecessary
Some DIY setups involve bracing the post with 2x4s before pouring concrete. That can work, but it’s not always needed—especially if the bracing isn’t anchored well. If the boards aren’t tied into the ground, they can still allow movement.
The reality: once concrete is in the hole and the post is plumbed properly, the concrete is what holds it in place.
How to avoid issues:
- If you brace, make sure braces are stable and secure
- Don’t rely on bracing to replace proper concrete support
6) Use Enough Concrete (and Follow Cure Time)
A fence post footing needs enough concrete mass to resist movement. At Ozark Fence, a common minimum standard is 80 pounds of concrete per hole.
If you’re using 60-lb bags, that usually means a bag and a half for many typical holes.
When filling, you generally want the concrete to stop 3 to 4 inches below the top of the hole, then backfill with soil after it sets.
Also, pay attention to cure time. Many mixes call for about 4 hours before the post can hold weight, and that’s worth respecting.
How to avoid issues:
- Don’t underfill concrete to save money
- Leave room to top with soil for a clean finish
- Let it cure before loading it with rails and pickets
Final Takeaway for Springfield Homeowners
If you want to avoid leaning posts, wavy fence lines, and early repairs, focus on the fundamentals:
- Correct hole width
- Correct depth for Missouri frost and soil
- Gravel only if accounted for
- Enough concrete mass
- Proper cure time
Fence posts are not the place to cut corners. Build the foundation right and the rest of the fence becomes easier—and lasts much longer.
If you’d rather not guess your way through it, Ozark Fence is here in Springfield, MO to help with professional installation and repairs that are built for local conditions.