You know, I wanted to build a garden box for myself as well. I was unwilling to because I didn't think I could do it right. I wanted to set it up on the side of my deck, but what about weight? That's a fair amount of dirt, maybe the weight might compromise the carrying capacity of the deck... Should I pre drill holes for screws? What kinda screws? Is it a factor? I ask because if I mess it up, and I have no idea what I'm doing so it's likely, I'll make a huuuuuge and unsightly mess for me and my neighbours that I wont be able to clean up without replacing things I damaged on my journey. That's more money, and probably expensive help, and a huge headache, and embarrassment. Even if I completely succeed in everything, how do I know this wont violate some strata laws where I placed it, or maybe I'll violate some sort of building code regulation. Maybe my deck already violates some building code regulation and if I bring attention to it I'll lose my deck.
I think if you're telling yourself that nothing could go wrong, that you are not very imaginative.
the same goes with servers,
the same goes with electricity,
the same goes with car repair.
It's just wood, except that the wood was treated with something toxic and now your flowers are dead and you've got a big headache in your backyard.