Anyone else uneasy about the sudden push for powder‑coated steel raised planters (think Herstera) as the “sustainable” default for small-space growing?

I get the convenience and aesthetics. But if we’re serious about sustainability, I can’t shake the feeling we’re being sold patio furniture with a garden attached. Before I buy more metal boxes, I want to challenge a few assumptions and see real data, not lifestyle photos:

Coating chemistry and soil safety: Does anyone have the Safety Data Sheet or technical data for Herstera’s powder coat? Is it free of PFAS, BPA, and heavy‑metal pigments (lead chromates, cadmium, etc.)? Is it certified for incidental food contact, or just outdoor durability? Has anyone done XRF on the coating or measured Zn/Cr/Fe in soil near a scratch after a season?
Microflake pollution: Powder coats chalk and flake under UV and abrasion. Are we just creating microplastic/paint particles in our soil food web? Any worm health tests or FTIR/Raman on soil from year 3-4 planters? I’d love to see even a DIY proxy: collect runoff/soil fines after scrubbing a weathered panel and analyze.
Galvanization and leaching: If components are galvanized or zinc‑primed, what happens in slightly acidic soil (pH < 6.5) with fertilizer salts? Any lab reports on zinc and aluminum mobility in planter leachate over time?
Heat island and water use: Dark metal boxes cook roots and drive evapotranspiration. Does anyone have side‑by‑side water usage and yield data for Herstera (or similar) vs. SIP totes or cedar beds, same media, same crop?
Embodied carbon payback: Steel is energy‑intensive. What’s the kg CO2e per unit of grow area, shipped from factory to doorstep, versus:
- DIY SIP from food‑grade tote
- Reclaimed cedar bed
- In‑ground bed with simple edging
  How many kg of produce do you need to grow before the planter “pays back” its embodied emissions relative to those alternatives?
Repairability and parts: After the first rust bloom or a crushed wheel, can we actually repair these? Are touch‑up kits compatible with the original powder chemistry? Are casters, drain grommets, and fasteners standardized and replaceable? Any exploded diagrams or parts catalogs from Herstera?
End‑of‑life: “Recyclable” in theory isn’t enough. Mixed materials (powder coat, plastic plugs, wheels) reduce recovery rates. Has anyone successfully stripped and scrapped one? What percentage by mass ends up landfill?
Liners and geotextiles: The go‑to fix is adding a liner. Great-now we’ve introduced PET/PP fabrics and potential microfibers. Anyone tried food‑grade HDPE sheet or EPDM pond liner as a barrier, and tested for off‑gassing or leachates?
Sub‑irrigation and water savings: Do any Herstera models support true sub‑irrigation reservoirs? If not, has anyone hacked a wicking reservoir into one and measured water-use reduction vs. top-watering?

If you have data, not anecdotes, please share:

Coating SDS or third‑party certifications (REACH SVHC, RoHS, EN 71‑3, food contact).
EPDs for the product or at least the steel components, and shipping distances.
Soil or leachate tests (Zn, Fe, Cr, Al) from aged planters.
Microflake/microplastic checks (even a DIY sieve + magnet + microscope).
Yield and water use logs over multiple seasons.

Proposed DIY test protocol for the community:

Scratch a small inside wall to bare metal, garden as usual for a season, then sample soil 1 cm from the scratch and 10 cm away; test pH, EC, Zn/Fe/Cr with a mail‑in lab.
Gently sand a weathered section over a clean tray, weigh collected dust, examine under a cheap USB microscope; optional: send a portion for FTIR.
Track irrigation volumes and harvest weights for one metal planter vs. one SIP tote vs. one wood bed with the same mix and crop schedule.

I’m not anti‑metal. I’m anti hand‑wavy “it lasts years so it’s sustainable.” If Herstera (or any brand) can show:

a transparent coating chemistry with food‑adjacency certifications,
modular parts with a 10‑year spares commitment,
a verified EPD and design-for-disassembly,
and a credible plan for end‑of‑life recovery,

I’ll gladly recommend them. Until then, why aren’t we steering renters and balcony gardeners toward SIP totes or in‑ground/shared beds that likely beat these on water, cost, and carbon?

Who’s got hard numbers-or wants to help crowd‑source a simple open LCA and testing spreadsheet?