A few things you may want to factor in when digging holes for your fence posts. First off, it’s a good idea to set your posts at least 1/3 of the height in the ground. For example, if you are installing a 6’ fence it would be recommended that you set your posts at least 2’ in the ground.

Make sure the post sits beneath the frost line. The frost line is the depth to which the groundwater in soil is expected to freeze.  The Frost line varies from region to region. The average frost line depth in Oregon is 18″.