Now we are here to establish where exactly we are going to put our 4x4 posts. Make sure that you take the measurement from the center of your first post to the center of your second post. Using your plumb line, making sure that everything is in a straight line we now know that this 6 foot level is exactly right. This is where our next post is going to be the center of our next post is here. Now we have determined where our 4x4 posts are going to go. Let's talk about the depth of this hole. Being the fact that this fence is a non-load bearing fence, a 2 foot x 14 inch hole will be just fine for this little picket fence. Now that I have got this dug let's see if it is wide enough and deep enough for our 4x4 picket fence post. Good.