The first green wall we build lasted 6 years, then it naturally disintegrated. I cut it apart, saved some of the plants and rebuilt, sturdier.
I used 4×4 posts set in concrete and attached used pallets. Then framed them on top and bottom with pressure treated 2X6’s. Finally, applied oil based stain.
The plant pockets were lined with spun landscape fabric, stapled in place. I filled the columns with Jolly Gardener CB HF. This sterile mix consists of Canadian peat, perlite, pine bark, and hydrafiber. It is lightweight, drains well but retains water. Then I sliced open the fabric between some slats and tucked the roots in the gaps.
I left 1″ of headspace at the top of each planting column to hold irrigation water, allow for settling, then added plants a month later.
Now for the variation on a theme. Instead of planting all the pockets, I filled half of them with rocks. A “gabion” is a sturdy wire basket or frame that holds aggregate, usually rip rap. It’s purpose is to prevent erosion and/or provide habitat for animals.
To make the rock columns, I lined them with hardware cloth, 1/2″ openings. I formed it first to match the inside dimensions of each pallet, then slid the wire down to the bottom. It was only 24″ high so I made two for each 4′ high pallet. Then poured in brook stone. For variety of wildlife habitat (snakes and lizards) I used 3/4″-1″ and 1 1/2″ to 2″.
On one column I made 6 holes with roofs and left it hollow for any larger critters. The first green wall here was a frequent home to two black racer snakes and I wanted to make sure they had plenty of places to roam and hide.