This 3D-printed design is a plant cage that also allows water to be delivered directly to the roots. This version is designed to be placed inside a separate planter.
Step 1: Design the Frame
The initial strut is created using the "Coil" command in Fusion 360. To minimize the amount of support material (scaffolding that needs to be removed and sanded after printing), I made the strut thick (1/2", 12.5mm) and tall (10", 250mm).
NOTE: While the "Pitch" is 10", I only wanted half a revolution, so the final height of the strut ends up being 5".
Use the "Pattern - Circular" command to duplicate the strut.
Repeat the above steps to create struts rotated in the opposite direction.
NOTE: If the watering feature is not needed, you can skip the next step.
Step 2: Hollow Out the Struts
A cross-section of the frame shows that the struts are solid. To hollow them out, again use the "Coil" and "Pattern - Circular" commands to convert the struts into tubes.
Why not just create tubes in the first place and save several steps? The intersecting geometry remains solid so water will not flow (imagine splicing two straws together in an "X" pattern). I learned this the hard way after printing and testing my first design. The sequence of cross-sectional images show how the struts are progressively hollowed out after each "Coil" and "Pattern - Circular" command.
Step 3: Other Design Features
For the rest of the design I added a support ring/reservoir where water can be added and several long, hollow spikes for anchoring/deep watering. There are many different ways to create these features, so I have simply captured screenshots to show how I created them.
Step 4: 3D Printing
I chose PLA filament for ease of printing.
Note: Since this design sits inside a planter, I was not worried if the printed model was not 100% leakproof.
The blue background visible inside the strut (3 o'clock position) confirms that it is hollow.
Step 5: Does It Work?
My previous model left the intersections blocked, so I was happy to see the water flow freely though this version.
Step 6: Files
In addition to the STL file for this design I have also included a "Tomato Cage" version for anyone that has access to a much larger 3D printer.