To restate what I have said before: I am a scrounger. I will plant into anything that will hold dirt (and is not contaminated). This week, I created an herb tower for myself out of 4 tires I found on the side of the road, and one my neighbour threw away.
Step 1: prepare the area with thick, nonglossy cardboard. In this case, the boxes from the pieces of chimney. Waste not, want not.

Step 2: paint and place tires.

Step 3: fill tires and space between tires with soil. (In this case, whatever bagged soil happened to be on sale at Kent)

Step 4: place and fill second tier with soil

Step 5: plant herbs

Sage, thyme, rock soapwort
Bottom front:
Peppermint, horehound (seeded)
Bottom back right:
Orange balm, greek oregano, spearmint
Bottom back left:
French tarragon, garlic chive, apple mint
Bottom left:
(Seeded) orangelo thyme, feverfew, lovage
This project took about 350L of soil and 3 cans of spraypaint (red x2, beige x 1). The tires and cardboard were free. Because my husband works where he does, worn-out tires are often available. I currently have 14 waiting for me to find uses for them. It keeps them out of landfill, and it also keeps my plants tidily contained in cute ways. All-around win.
Once the herb bed was finisbed, I planted trees. Both of the new heartnut are in the ground, now, and 4 of the 8 honeylocust. On the way to planting site for the honeylocust, I found at least 2 large patches of wild blueberry bushes. Happy surprise! That area will be perfect for cranberry, as well, in future.