Spacing the Posts
Once you decide on the type of fence you're installing, measure the length of the fencing panels. The purpose of the fence, terrain and type of fence will determine the amount of distance between each post. Typically, fence posts are spaced about 6 to 8 feet apart. Drive a wooden stake into the ground where each post will go, beginning with the corner posts. Lay a rope between the corner posts in a straight line as a simple guide for aligning the other posts. Once the stakes are in place, go back and measure the distance between each stake to check they are no more than 8 feet apart.
Prepare Post Holes
Maximize the strength of your fence by digging post holes equal to one-third of the length of the posts. Use an auger or post hole digger to remove dirt at the site of each post hole, digging holes 10 to 12 inches in diameter. Once the hole is deep enough, make it wider at the bottom to anchor the posts and reduce the chances of frost heave damage. Fill the hole with 6 inches of gravel and tamp it down with a manual tamper. Tamping gravel forces the stones to pack together into a nearly solid base.
Setting the Posts
It's advantageous to have a helper hold the post in the middle of the hole so you can focus on securing it. Use a level to check that the post is plumb in the hole. Use a hand shovel to add 3 inches of gravel around the fence post. Pour stone dust over the gravel so it goes into the crevices between the rocks and tamp down the gravel. Continue adding gravel and stone dust in 3-inch layers and tamping each layer down until you reach the top. Once the gravel is ground level, pour water over top to moisten the stone dust. Stone dust will harden to the rocks like concrete when it dries.
Finishing the Post
Harsh weather conditions are a common cause of fence damage. Protect your fence by adding a 2-to-3-inch mound of gravel around the base of each post. Pack stone dust over the gravel, moisten the mound and tamp it down. The mounds add extra support and direct water runoff away from the post, preventing rot.