A stackable magnetic support collar for small seedlings in the AeroGarden. 
(I just wanted a magnetic version)

The collar comes apart in halves and is easy to install and remove. It also has side vents for airflow and to put stems through if needed.

The model has several small pockets that can accommodate 4x2mm (4mm diameter 2mm thick) magnets, or two stacked 4x1 magnets. 

Printing Tips:

• Print at 0.2mm layer height
• Add pause gcode in your slicer and drop in some magnets
• If your print head is magnetic, try a dab of superglue on the side of the magnet, careful not to get any on the top of the layer and let it set fully before resuming the print.
• The pockets on top are optional and help with stacking stability a little, but aren't necessary unless you plan to stack several. If you use these, ensure that your chosen magnetic pole prints upward in all copies you print.
• Each inside face of the collar can accommodate up to 3 4x2mm magnets (12 per full collar). Filling a single slot produces a weak attraction which should be sufficient to lightly hold the collar together. Two magnets per face creates a sturdy attraction, and a third can be added if you have weaker magnets, but is redundant otherwise. No matter how many you add, make sure that the poles are all oriented in a clockwise or anti-clockwise direction around the collar (consistency is key) so that any two random collar halves will stick together when rotated.
   

The plug seen in the back of the AeroGarden can be found here

Enjoy!