ferrocement for a wicking bed?

I have been building an urbanite raised bed, which is going to be a wicking bed eventually. Looking at the pointy concrete chunks, I think that an EPDM liner would end up in trouble. What if I put mesh against the walls and bottom and troweled cement over them? This would also be cheaper then a plastic or rubber liner, and less likely to be toxic.

To see what I am doing, follow this link to my permies project thread. https://permies.com/t/39202/projects/pics-models-project-advice-criticism#315610

It should work, with a good rich mortar mix. You might not even need the mesh for most of it. Your urbanite has plenty to bite onto.

Worst case, you have made a smooth liner for the EPDM.