A friend and me were discussing the best fill to put in a fence post hole for an 8' long 4"x4" or 6"x6" square post for fencing a garden. He says to use class 5 gravel. I say to use about 1/2 fine barn lime mixed with 1/2 soil from the augered hole. My argument is that the barn lime mixed with our sandy loam fertile soil would be more stable in a well drained soil where we get an average amount of rain, whereas the class five gravel would have air pockets and be somewhat loose. Also, I don't want any chemicals leaching into my garden from recycled materials used in class 5 gravel. We used my barn lime method (an old farmers' trick) on a 75 " long 8" high solid hardwood fence 4 years ago and have noticed no shift in the posts despite high winds and many torrential downpours. I placed the posts in about a 2 1/2' hole, did the mix, watered it and let it set for a few days. Neither of us want to use concrete mix. Too hard to chip out if need be.
Your comments please. Thanks.