Yep, you can set fence posts without concrete, and there are some really good reasons for doing it that way. Some people believe that you should not set wooden posts in concrete, unless you want to replace rotting posts in a few years. Both the wood and the concrete expand and contract depending on the weather, and that can open up tiny spaces between the post and the concrete that allow water to get in and stay in. Water + wood equals rot.
Instead, try setting your wooden posts in a mixture of soil and gravel. Gravel provides a natural drain for water, and the soil and gravel work together as a strong anchor for your post. Keep reading to see how stress-free it is!
Use a posthole digger to dig a hole that is as close to the diameter of your post as you can get it. Dig deep! You should plan on burying about 1/3 of your post below ground level. That means, if your post is 8 feet long, you need to bury 3 feet of it.
Before you stick the pole in the newly dug hole, place a hunk of broken concrete or a pointy rock in the bottom. This provides a footing for the post to sit on, and that’s much better than setting it on soil. This isn’t a step that you skip!
Now, have someone hold the post level vertically, or brace it securely into place while you backfill the hole. Backfill the hole with equal parts crushed gravel and soil, going slowly, and tamping down between layers to make sure it’s well-packed.
Once you reach ground level with the dirt-gravel mixture, use it to pack around the post in a slight hill so that water will always run away from the post.
Finally, don’t forget to either bevel the top end of the post at a 45-degree angle with a chop saw, or else cover the end with a protective cap. This protects the end grain, which will soak up any rain or moisture and cause your post to rot.