When we "planted" in ground around here BITD, we need the bottom of the hole below the frost line(4ft), with ~2x2x1 cement footing surrounding the pole. Otherwise the frost was guaranteed to move it. If the soil is of lighter consistency a pad surrounding the pole 3 to 4 ft on the surface after packing (using a lot of water) the back-fill. One way to find out where your frost line is is ask a contractor how deep the bottom of footings are put for a house. That's how deep to "plant" your pole. Some owners did install the pole themselves, and turned out too shallow, and had leaning poles in no time. Some re-planted them, some put guy wires, for a mowing nightmare.
By far the most often used around here was the floating slab outlined in one of the threads referred to. Only needs readjustment the following spring and fall, then will settle to only now and then. I've probably only readjusted my pole 3 times, after the first year, since the mid 80's.
Today there's 18+ inch augers on Bobcats, for boring outside sump pumps and planting poles for pole sheds. That would have been nice to rent BITD. Rent $ is the same to dig 3ft or 6.
Biggest factors are soil type and frost or not. Ask a concrete contractor where they put footings in your area. It's also probably stated in building codes. I'd rather overkill slightly than under. It's not fun redoing the pole. just my 2¢
Phlatwound- 3ft deep in heavy soil,and I'll add, no frost to battle. Boy I wish we only had to dig that far BITD.
All my dishes are up high.
