Ed Schroeder shared this handy garden tool with us:
"This is a cheap and easy tool to set steel posts for garden trellises.
Schedule 40 PVC, 3/4 inch inside diameter, is sturdy enough, even in heavy soil because it has a 1/8" thick wall. Ed's Drawing of Post Jet Assembly
These are all slip fittings that have to be glued with 1) PVC pipe cleaner; the purple stuff. 2) the actual glue is really a solvent the "melts" the pieces together for a very strong and water proof bond. The garden hose adapter does what the name says; it adapts the tool for connection to a garden hose. Turn on the water and jet a post hole. It's easier than using a sledge hammer."
And from Regine: "I bought the parts with Ed's hand drawing. I decided to go for metal and I bet they would be useful to dislodge invasives with big roots." Regine's Post Jet: