This morning Tony and I finished filling the bed with soil mix and planting the banana plants -- five of which were in 25 gallon tubs. Afterwards, I watered the whole thing down with a solution of 10-20-30 (100ppm P) to encourage root growth, then innoculated the soil around the plants with Gro-Power "Pure & Natural" (1/2 cup each).
It's almost finished. On Wednesday I'll have time to install the irrigation and cover the bed with a thick layer of 1-inch diameter mulch.
The soil mix I used was half compost and half "dense materials" that would keep the plants from tipping over but also provide aeration and drainage. I used:
6 parts humic compost
2 parts local "loamy clay"
2 parts sand
1 part scoria
1 part worm castings
Here's how it looked at noontime. The photo is taken from about 15 feet above the ground level of the planter bed:
