Totem: Open-Source Solar Aeroponics for Off-Grid Vertical Farming

Vertical farming does not have to mean a warehouse with a six-figure power bill. On September 21, 2026, pv magazine reported on Totem—an open-source, solar-powered vertical aeroponic system from Mexico’s Northwestern Center for Biological Research (Cibnor), documented in the journal HardwareX.

What’s in the tower

Totem stacks eight modules (growth, reservoir, pump, filter, inlet-drainage, control, power, solar) built mostly from commercial PVC. The 1.5-meter growth tower holds 24 planting sites in six staggered rows; roots hang in an enclosed chamber while a 12 V diaphragm pump pushes nutrient solution through an Azud Modular R 100-mesh filter to 24 low-pressure misting nozzles. Excess drains by gravity back to the reservoir. An ESP32-Wroom runs the pump schedule and streams telemetry to a web GUI over Wi-Fi.

Off-grid power math

• 50 W polycrystalline PV → charge controller → two parallel 12 V / 12 Ah batteries (288 Wh nominal, ~2.7 days without sun)
• Trial load ~44.9 Wh/day vs estimated PV yield ~136.5 Wh/day under conservative local conditions
• Itemized materials ~$719.51

Basil trial results

In a 55-day basil run, the pump sprayed 30 seconds every 30 minutes (48 cycles/day). The system stayed online and delivered two successive harvests. Authors stress this proves technical feasibility—not a multi-crop agronomic bake-off—and call out automated pH/EC control as future work. Hardware, firmware, and GUI files are published with the paper.

Why aeroponics + PV fits off-grid CEA

Aeroponics mists roots in air instead of drowning them in substrate, which can cut water use when the unused solution recirculates. Most commercial CEA still assumes grid power for pumps, lights, and climate. Totem’s contribution, as the authors frame it, is documenting the full stack—structure, hydraulics, electronics, software, and solar—with an itemized bill of materials so schools, NGOs, and makers can rebuild without reinventing every PVC coupler.

Limits to respect

A 55-day basil demo under Mexican test conditions does not prove lettuce, strawberries, or year-round yields in a cloudy climate. There is no automated pH/EC loop yet, and long-term nozzle clogging, PVC UV aging, and battery cycle life need multi-season data. Think of Totem as a transparent reference design you can fork—not a plug-and-play farm-in-a-box with agronomic guarantees.

Rocks take

Perfect maker/research story for off-grid and education use cases; not a turnkey commercial farm. If you replicate, budget for sensors, nutrient discipline, and climate—not just PVC. Source: pv magazine summarizing HardwareX.

FAQ

Is Totem for sale? No—open-source research prototype with public design files.

What crop was tested? Basil, two harvests over 55 days.