Layers to Leaves: Modular 3D-Printed Hydroponics Components

Summary

Layers to Leaves is a suite of 3D-printable hydroponics components published as a peer-reviewed, CC0 (public domain) article in PLOS One (April 2026) by Ethan A. Shaw, Suraj K. Chandramouli, and Michael P. Dzakovich, with funding from the USDA Agricultural Research Service. The parts assemble into a vertical drip hydroponics system in either a Single Tower or Double Tower configuration, with stackable planting modules (3-, 4-, and 5-cup variants), spacer modules, a distributor, and a custom reservoir lid sized for a ULINE S-20588GR 20 L tote. The system was validated in a salinity study growing four spinach cultivars, where its performance was statistically comparable to traditional deep water culture (system type explained only 0.02% of total variance). All STL files are hosted on the NIH 3D database (entries 3DPX-021941 and 3DPX-021942), and a step-by-step assembly protocol is published on protocols.io. Because every part prints on hobbyist FDM printers from inexpensive PLA or PETG filament, the suite is designed to democratize hydroponics for classrooms, growth chambers, and research labs alike.

Guiding Principles

Modularity — The entire system is a mix-and-match ecosystem: tower modules, spacers (standard and extended), cups, and a stream breaker can be reordered, rotated, added, or removed, and individual parts (e.g. plant cups) can be reused in entirely different hydroponic setups.
Open Source — The article is CC0 public domain, STL files are freely downloadable from NIH 3D, and the assembly protocol is openly published on protocols.io; users are explicitly encouraged to modify parts for their own needs.
STEM Integration — The paper provides a validated experimental context (salinity treatments, EC/pH management, fresh/dry weight data, R statistics), making the system a direct vehicle for hypothesis-driven biology and data-literacy instruction.
Community Self-Sufficiency — By replacing commercial hydroponic towers with parts printable on household-grade printers at a fraction of the cost, it lowers the barrier for schools and communities to run their own growing systems.

Learning Outcomes & Transferable Skills

Learners gain hands-on 3D Printing practice (slicing, infill/orientation trade-offs, material selection between PLA and PETG), applied Biology (germination, transplanting into neoprene collars, salinity stress, harvest metrics), Water Chemistry (mixing Hoagland's solution, maintaining pH 5.5–6.0, interpreting EC in dS/m), Systems Thinking (pump flow rates, light gradients across tower blocks, nutrient recirculation), and Data Literacy (randomized complete block designs, ANOVA, comparing systems statistically). Because the system is validated for research, students can run genuine controlled experiments rather than demonstrations.

How to Replicate or Build On It

Read the PLOS One paper first — it contains full cost tables, printer-compatibility analysis, and validation data.
Download STL files from NIH 3D: Single Tower (3DPX-021941) and Double Tower (3DPX-021942).
Follow the assembly protocol on protocols.io (dx.doi.org/10.17504/protocols.io.e6nvw4pw9lmk/v2); a companion spinach germination protocol is also on protocols.io.
Slice with 20% infill, ≤0.2 mm layer height, grid infill; print in PLA or PETG.
Source the external parts: ULINE S-20588GR 20 L tote (or equivalent dark HDPE bin), a ~250 GPH submersible pump, ½" ID vinyl tubing, and 2" neoprene cloning collars.
Build on it by re-scaling plant cups for taproot crops, adding PVC fittings for an external pump, or remixing modules — the authors explicitly invite adaptation. Parts are themselves adapted from Parametric Net Pot & Net Cup Collection-era community designs (Thingiverse user 'boundarycondition', thing:3405964).

Considerations & Constraints

Cost: Baseline assumes ~$19 per 1 kg filament spool, 20% infill; the paper's Tables 2–8 give transparent line-item costs for a default 3-module Single Tower. Cumulative cost is lower than comparable prefabricated units. External hardware (tote, pump, tubing, collars) is additional.
Skill Level: Beginner-friendly printing and assembly, but running the nutrient regime (EC, pH adjustment with H2SO4/KOH) suits Intermediate learners or requires educator supervision.
Space/Climate: Vertical footprint suits classrooms, growth chambers, and greenhouses; designed for indoor/controlled environments with overhead lighting — lower tower levels receive measurably less light (DLI 15.3 vs 19.7 at the top).
Tools Required: FDM printer with ≥ ~178×178×145 mm build volume (a Prusa MK3S+ class machine or larger prints every part in one piece), slicer (PrusaSlicer), stainless-steel nozzle recommended to avoid lead contamination from brass.
Ongoing Maintenance: Nutrient solution changes, pH/EC monitoring, and — for runs over five weeks — a strategy to keep roots out of the pump intake; the authors recommend an external pump for long experiments.
Access Barriers: English only; best suited to leafy greens/herbs — taproot crops don't fit the stock cup diameter; PETG preferred over PLA for long-term waterproofing.

Prerequisites

Parametric Net Pot & Net Cup Collection (conceptual ancestor of the plant-cup modules)

Primary Source

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0346497 (CC0; STL files at https://3d.nih.gov/entries/3DPX-021941 and https://3d.nih.gov/entries/3DPX-021942)