AquaCrown — Hydroponic Aquarium Plant Holder

Lavender Gooms — Functional designs for Bambu Labs printers. No supports, no glue, no hardware. Parametric OpenSCAD source included with every model.

The AquaCrown is a three-piece gravity-fit plant holder that sits in the back gap of an aquarium lid, letting you grow terrestrial plants hydroponically in your tank. The plant's roots dangle into the aquarium water while the crown stays above the waterline — the plant breathes and grows naturally while the roots pull nutrients directly from the tank.

How it works:

- Crown Cup — Diamond lattice basket that holds the plant's crown above the waterline. Sits on the glass lid and rests on the tank rim for support.

- Root Cup — Nests inside the Crown Cup, extends below the glass lid into the water. Roots grow down through it into the tank.

- Comb — Slides between the roots under the crown. The Root Cup opening is wide enough for a full root mass to pass through freely, but that means the crown could fall through too. The Comb bridges across the opening to support the crown while keeping the root path clear.

The three pieces nest together — no clips, no glue, no hardware.

Designed for plants like:

- Monstera deliciosa — Thrives hydroponically with roots in water. Grows more compactly than in soil, making it perfect for an aquarium setup.

- Peace lily (Spathiphyllum) — A classic hydroponic plant. The crown specifically needs to stay above water to avoid rot, which is exactly what this holder does.

- Spider plants (Chlorophytum comosum) — Hardy, large root mass, and they'll send runners trailing over the tank.

- Syngonium / Arrowhead Plant (Syngonium podophyllum) — Compact crown with a dense root system. Transitions to water roots without issue.

- Chinese Evergreen (Aglaonema) — Solid crown structure with a substantial root mass. Roots absorb nitrates and help maintain stable water chemistry.

- Dumb Cane (Dieffenbachia) — Upright growth with a sturdy crown that sits well in the holder. Naturally grows in wet tropical habitats.

Generally works for any tropical plant that has a compact crown sitting on top of a substantial root mass — the comb supports the crown while the roots grow down through the holder into the tank. 

Preparing the plant:

1. Remove the plant from its nursery pot

2. Soak the root ball in a bucket of water to loosen the soil

3. Gently spray or rinse the roots until all soil is removed — you want bare roots, no soil going into your tank

4. Tease the Comb through the roots under the crown — work it in gently, sliding it between the roots so the crown sits on top of the comb and can't fall through

Assembly and install:

1. Nest the Root Cup into the Crown Cup

2. Feed the roots down through the Root Cup opening — this can take some patience with a big root mass. Gentle shaking and teasing the roots through a few at a time works well. Take your time.

3. Seat the plant and Comb down into the Crown Cup

4. Drop the assembled holder into the lid gap — the Crown Cup rests on the glass lid and tank rim, the Root Cup hangs below into the water

Specs:

- Print time: ~3 hours 45 minutes (adaptive layers, PETG)

- Filament: ~64g PETG

- Supports: None

- Tested on: Bambu Labs P2S

- Plate footprint: ~104 x 167 mm (all 3 pieces)

- Tallest piece: 80 mm

- Pieces: 3 (all on one plate)

Dimensions: Sized for a 40-gallon breeder aquarium with Aqueon Versa-Top lid (back gap ~41mm wide). The parametric OpenSCAD source is included if you need to adjust for a different tank.

Recommended filament: PETG (handles humidity and occasional splashes better than PLA)

Print settings: Default Bambu P2S profile, 0.20mm layer height, adaptive layers recommended. No supports needed. The 3MF contains all three pieces (Crown Cup, Root Cup, Comb) and they print together on one plate.

Why I made this:

I have a 40-gallon breeder aquarium with an Aqueon Versa-Top glass lid. The lid has a narrow gap along the back with a flexible acrylic strip for routing cords and tubing. I removed that strip entirely to open up the gap, and I needed something that fits in that space between the lid and the rim to grow a monstera out of the tank. Existing hang-on-rim planters are basket-style — they give you above-waterline space, but the plant just sits in the basket and you need LECA or similar media to keep the crown from submerging. I wanted something that supports the crown above water without filler media, and the open bottom design lets the roots have full room and freedom to grow down into the tank.

Printing tips: All models are designed for the Bambu Labs P2S with default profiles — no custom settings needed. Enable adaptive layers in Bambu Studio for faster prints. STL files are included if you prefer your own slicer settings. Questions or issues? Leave a comment and I'll help troubleshoot. If you print this, I'd love to see it — post a make!