So my neighbor has had this dead tree snag next to his driveway for so long that it was threatening to fall over and block it. He decided a couple months ago that it had to go and fired up the chain saw. It didn't take long to get it down, and we carted it over to my hugelkultur staging area. Lots of rotten wood for me to build more mounds with!
But back to the stump that was left. There was a large cavity extending below grade, so I poured in a wheelbarrow load of sand, threw some squash seeds on top, and raked some of the rotted wood on top of it all.
Fast forward to today and what do we have?
That butternut squash is doing great! There are two vines running out of the top and the right side of the picture, each about 10' long with a hefty size squash. The only thing I could have done better would have been to add 2 wheelbarrow loads of sand to the stump. That's quite a bit of volume eaten away below the top of the stump.