My neighbor made vertical succulent planters from wooden shipping pallets. These will not be long lasting, but they were very inexpensive and easy to build.
Spaces between the boards on the front were filled with narrow wooden slats nailed on. They are indicated by the arrow on the left. On the back of the pallet, landscape fabric was stapled in open areas to hold soil in. The fabric, indicated by the right arrow, can just be glimpsed. Because of the substantial weight of the pallets and soil, they are leaned up against the fence rather than hung upon it.
Drip tubing connected to the irrigation system will provide water, making this planter very low care.