Kratky Jar Sleeve for Indoor Mason Jar Hydroponics

Opaque black mason jar sleeves block light to keep algae from growing in the water of Kratky method hydroponics systems. They are 3D printed in environmentally friendly black PLA plastic.

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.

The sleeve is 4.25"/108mm in diameter, and 5.75"/146mm in height.

I can print the jar sleeves in other colors upon request, but that may affect their opacity, as lighter or translucent colors will allow light through. Please message me for details.