You should be able to find southern pine—or whatever other wood you choose to use—at a local hardware store or lumberyard.

Because cedar is high in demand, it’s also more expensive than, say, yellow pine. If you live in a fairly arid environment, fungi may not be much of a concern for your posts.

However, although these woods are naturally adverse to soaking up water, they still need to be treated! Always buy treated redwood or cypress—or treat your own—to ensure that the posts stay rot-free for years. [5] X Research source

Douglas fir and lodge-pole pine are what’s known as “refractory” species of tree. They’re typically treated only by professionals, since treating them requires additional steps that can’t be performed at home. For example, the lumber must be steamed to make it more receptive to the chemical wood preservatives that are then applied.

Woods that haven’t been pressure-treated will have a looser structure, making them more permeable to water, bacteria, insects, and other rot-causing agents.

If you need to cut one or more of these treated pieces of lumber to the size you’d like for your posts, make sure to re-treat the cut portion with a copper-naphthenate preservative. Associations other than the AWPA don’t give their treated wood this type of rating.

Giving your posts a thorough soaking in a wood preservative will go a long way in preventing them from rotting. [10] X Research source

If you were to skip applying the wood preservative, you posts would likely begin to rot within 6 months, regardless of whether or not you set them in concrete.

Regardless of whether you’re using the post for a fence or a mailbox, remember that water causes rot. The best way to keep your post from rotting itself out of the ground is to sink it in cement.

This will prevent the post from rotting by keeping it constantly dry. You can purchase gravel at a local hardware store or landscaping-supply business.

If you’re mixing in a cement mixer, you won’t need to stir with the shovel. Just flip the “on” switch and stand back while the machine spins for 5–8 minutes.

If you have a friend or family member nearby, ask them to help you with this step. The second person can hold the post upright while you move on to the next step.

If there’s any open ground between the cement and the top of the hole, your post will be vulnerable to soaking up moisture at that spot.