Building a Self-Watering Planter with 3D Printed Parts

Building your own self-watering planter is one of those projects that’s immediately useful, looks great on a windowsill, and teaches you a ton about designing for functional prints. Let’s get into it.

Why 3D Print a Planter?

Sure, you can buy a plastic planter at any garden center. But where’s the dopamine in that? 3D printing your own means you get to:

• Choose the exact dimensions to fit your space
• Design built-in drainage that actually works
• Use materials suited to the task (PETG for water resistance)
• Iterate until it’s exactly right

Design Overview

The planter is two-piece: an outer decorative shell and an inner reservoir liner. The liner holds water and a wicking system draws moisture up to the roots. The outer shell is purely aesthetic — print it in whatever color catches your eye.

Key dimensions

• Outer shell: 200mm × 120mm × 180mm
• Inner reservoir: 190mm × 110mm × 80mm
• Wick holes: 8mm diameter, evenly spaced

Print Settings

For the inner reservoir (holds water, must be watertight):

• Material: PETG — mandatory for water contact
• Layer height: 0.15mm for tighter layers
• Infill: 40% gyroid for structural support with waterproofing in mind
• Walls: 5 perimeters minimum
• Supports: Yes, for the wick hole overhangs

For the outer shell:

• Material: PLA works fine, or PETG if you want to match
• Layer height: 0.2mm — it’s decorative, save some time
• Infill: 15% is plenty
• Walls: 3 perimeters

Assembly

1. Print both parts. Post-cure the reservoir if printing in resin.
2. Sand the rim of the reservoir where it meets the shell.
3. Cut three 15cm lengths of cotton rope for wicks.
4. Thread wicks through the holes so they hang into the reservoir.
5. Fill reservoir with water (use the fill port on the side).
6. Add potting mix to the shell, laying the reservoir liner inside.
7. Plant your greens and watch them thrive.

Making it Watertight

PETG printed at 0.15mm layer height is very close to watertight but rarely perfect off the bed. Two options:

1. XTC-3D epoxy coat: Brush on one layer, let cure. Fast and effective.
2. Spray sealant: Multiple coats of Rustoleum 2X Clear Satin. Takes longer but easier to apply.

I went with XTC-3D on mine and it’s been holding water for three months with no issues.

What I’d Change

Looking back at v1.0, I’d add a water level indicator window on the side — a small clear filament window so you can check the reservoir without tipping the planter. That’s on the roadmap for v1.1.

All STL files are linked in the project page. Happy printing!