Opaque black mason jar sleeves block light to keep algae from growing in the water of Kratky method hydroponics systems.

3D print this ready-to-go STL file in your color and material of choice; I use black PLA. Printing in other colors or with transparent PLA may allow light through; do so at your own risk. You won’t need to use a raft, brim, or supports provided you have a properly calibrated and sticky build plate.

Designed for quart sized mason jars, these sleeves block light from all sides except for a narrow viewing window. For better visibility inside the jar, I recommend slipping a piece of white paper inside the sleeve. A helpful cutout located halfway up the viewing window indicates the maximum fill level. Do not refill your Kratky jars above this tab or you risk drowning your plant’s roots.

Printing recommendations:

• Black or other fully opaque dark color recommended; material doesn't matter so much but I use PLA
• Inside brim recommended if your build plate has adhesion issues
• Supports not required

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Don't want to print your own Kratky jar sleeves and would rather buy a pre-made version? I have the pre-made sleeves available here.

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Licensed for personal use only. Commercial licenses available here. Please do not redistribute this file or any modified derivatives of this file in any way, or sell your own prints made from this file. Thank you.