UPDATE: 7/24/2019
I'm splitting this into multiple projects as they are fairly independent at this point (this was meant to be modular...) This contains only the tower components now.

Other parts are here:
Herb Garden: https://www.thingiverse.com/thing:3768611
SoloSprout: https://www.thingiverse.com/thing:3768626
Fog unit and other parts: https://www.thingiverse.com/thing:3768838

So this is a project I've wanted to work on for quite some time.

So far, plants seem to be doing reasonable well, but it's only been about a two weeks since I've moved them into this system and I'm still waiting to move more as they're just sprouting now. Only the mint isn't doing well, but that was a purchased plant, not grown from seed; I think it's just a disappointmint.

The system has the herb box and two towers (6 tiers each once I have plants to fill them; I might remake them to resemble LoTR towers...) and fog flows through the entire system pretty well (I might open a few holes intentionally if I do that redesign). Flow rates per line are adjustable via an inline ball valve, but it doesn't seem necessary at the moment.

I've tested the system for one or two towers
40mm fan running 4.5-6v for one tower or 8-12v for two)
Timer runs 10m/50m intervals

I'm using 1/2 inch tubing for all fog and drain lines.

Most of the parts are PETG, but some parts are flexible (the seals).

Modified:
1) the alb_7_41_Pot_04 from albaniac was rotated and renamed to "EasyPrint Pot" as it's the only one I use
2) The lid from boundarycondition had the holes removed as you do not want any of your mist escaping

Unmodified:
2 and 3-way planting modules -boundarycondition
Blank_cap -boundarycondition
Filtration mesh holders -boundarycondition
80mm spacer module -boundarycondition
Filling cap parts -boundarycondition
Dispenser module - CrispyMR.