Printing planters and vases that hold water

A printed pot is made of thousands of thin layers. Water finds the smallest gap between two of them, so a pot that looks perfect can still sweat or drip. These settings and checks make PLA (and PETG) planters and vases watertight.

The easiest way: a nursery pot inside

Planters from the Planter generator are sized for a store-bought nursery pot (S 12 cm, M 14 cm, L 17 cm, XL 21 cm). The plant stays in its own pot and the printed planter only has to hold the little water that runs through. Pots with the screw-on tray have drainage holes on purpose: the water goes to the tray, not through the walls.

Vases and planters without holes have to be watertight themselves. Then:

Slicer settings

• Walls: 3 or more (4 for vases). One wall is never watertight.
• Bottom: 5 layers or more, and a monotonic top and bottom pattern so the floor has no gaps.
• Line width: 0.45 to 0.5 mm with a 0.4 mm nozzle: wider lines press into each other.
• Flow: 100 to 105 %. Tune top surface flow and first layer flow in the Print Optimizer for the filament you use: under-extrusion is the main cause of leaks.
• Temperature: 5 to 10 degrees above your usual for PLA, so the layers fuse well. Slow the outer wall down (60 to 100 mm/s).
• Seam: aligned or at the back, and scarf seam on where your printer supports it. A gappy seam is a line of tiny holes.

Vase mode

Vase mode (spiral) prints one wall, so it only holds water with a wide line (0.8 mm on a 0.6 nozzle) and slow printing. Use it only where the texture allows: a smooth vase or one with shallow flutes or waves. Deep textures (pinecone, petals, diamonds, stone) and every planter from the generator print in normal mode with 3 or more walls.

After printing

• Test it: fill it with water and stand it on kitchen paper for 24 hours. A damp spot shows where it leaks.
• Seal the inside if needed: a thin coat of two-part epoxy (brush or pour and turn), or a clear acrylic or polyurethane varnish. Let it cure fully. Do not use sealed pots for food or drink.
• Small leaks: a drop of thin CA glue (superglue) soaks into a pinhole from the inside.

Material notes

• PLA is fine indoors. It softens above about 55 degrees: not in a hot car or in full sun behind glass, and not outdoors in summer.
• PETG holds water better at the layer lines and stands warmth and sun better: a good choice for pots on a sunny windowsill or balcony.
• Matte and silk PLA are a little more porous than basic PLA: use 4 walls.

Quick checklist

• 3 to 4 walls, 5 bottom layers, monotonic floor.
• Flow tuned in the Print Optimizer, temperature a little higher.
• Seam at the back or scarf seam.
• Water test for 24 hours; seal the inside if it sweats.