Watersealed floor

Hey just trying to get some input on my situation. I want a waterproof floor with a bit of a lip. besically a big tray I can sit all my pots in and water to hearts content. Its about a 2.5'x7' space so what would be the best way? I was thinking just plastic sheeting and waterproof caulking lol? Idk would this work? What thickness plastic should I use? Any other ideas I can see the caulking being problematic as I don't want that mixing with my nute water and my plants sucking it up from the bottom. ANY help would be greatly appreciated!

id paint the floor white with a few nice and thick coats, and caulk all the cracks

Carpet

Build a frame out of 3/4 " plywood, use 2x2' or 2x4's to make your tray, caulk and seal will a pvc paint, I would use two plus coats.
I would also raise the platform off the ground using short legs, and support the platform in multiple places.

Build the frame, as above, then fiber glass it?

Get an appropriate sized tarp and line your floor w/ it.

Go to Lowes or HomeDepot and get a piece of shower pan material. rubber like material comes on roll about 4 ft wide I think, really cheap solution. I used it in my first cab. It's extremely tough...lasts forever. It can be glued with pvc cement to make corners, seams, etc.

And all this water you plan to spill - what will you do about that? Raise fungus gnats and mold? Get real, dude.