Helped my cousin put up a section of fence a couple months ago, the old one had rotted and fallen. Original fence posts were set in concrete but no gravel, looked like termites helped take it down, but that fence must have been there decades. Rented an auger (two actually) and it was slow going thanks to the San Diego clay. Dug as deep as we could, not quite 1/3 down but close, a little gravel and then concrete. Seemed the posts where we mixed the concrete then poured are a little sturdier than the ones we poured the concrete bag and dumped water on top, but that may be due to other factors as well.
No freezing to worry about, I would have preferred to be more thorough but digging those holes was a bear, the clay, rocks and misc chunks of concrete made for 4 guys bearing down on a 2 man auger. As long as it lasts a few years he will be happy.
Will use the "soak in preservative" tips mentioned above when we tackle the rear and other side sections.
