Will smothering with cardboard and mulch work on St Augustine? I'm pretty sure that is what I have.
Smothering with cardboard works everywhere it is tried. You will have a REAL problem if you cut any lines. Also, you have total control over your garden soil bc it will be what you add. You will need to build a bottomless frame to hold the soil inside. Generally no wider than 4' for a raised bed bc wider makes it almost impossible to pick what is in the middle without walking into it.
FYI, check with your friends to see who has ordered recently from Amazon. Most people are Swimming in cardboard, AND grocery stores here restock on Tuesdays and will give you cardboard if you ask.
There are lots of vegetables that don't require room for super deep roots. Almost all cool season vegetables have shallow roots and tomatoes can be taken from pots, laid on their sides and buried only inches deep and they will grow roots all along the buried stem. They are pretty much the only staple vegetable that does this. Still lots of vegetables grow great in a container and many lightweight containers are pretty deep.
Since this is a back yard you could buy 5 gallon painters buckets for less than $5/each, drill a few holes in the bottom for them to drain (or smack the bottom with a hammer for a crack) and use those for containers. They also have a handle to use to move them. Not too pretty but
very functional.
If you also buy a lid for each you can store your supplies off season in them. I use them to carry water for my horses and chickens. Last Fall a friend had a bumper crop of pears and I bought nine of them to use to harvest, they are that sturdy, but very lightweight.
https://www.lowes.com/pd/United-Sol...lutions&CAWELAID=&kpid=1000462835&CAGPSPN=pla{ifdyn:dyn}&k_clickID=bi_272385392_1299622912510932_81226464441985_pla-4584826051602640_c_&msclkid=37f52b40194e1ee681147703a9e31b7c
Since they are so much cheaper than anything labeled a garden pot, you could also pick up a couple of them JUST for your tools.
