Strawberry Plant Growing Support

What epitomises summer better than fresh strawberries? The best and freshest strawberries are those picked from your own garden. To maximise the quantity of good fruit from your plot, this simple device will raise your plants from the ground to increase air flow and reduce damage from damp (and slugs).

Similar things are available from the all-encompassing Amazon among others, but where's the fun in that?

The support was designed as two semi-circular meshes so that they can be introduced around the plants without damaging them. The meshes can be linked together for stability and raised off the ground.

One important design parameter is the size of my printer's build plate - your milage might vary.

This is a 3D printing project for which I used:

FreeCAD

Other free (and paid for) 3D design programmes are available, use the one you're most familiar with. FreeCAD is parametric which basically makes it much simpler to tweak the design.

Ultimaker Cura

Again, if you prefer a different slicer, use it! I'm used to Cura and mostly it turns my designs into gcode that works in my set up.

3D printer

I have a Creality Ender 3 Pro with the upgraded mother board, BlueTouch sensor and a glass build plate. It has been working for a couple of years without significant problems. A Raspberry Pi running OctoPrint provides a simple interface, over WIFi, to my main desk PC.

PLA filament

The interweb suggests that PETG would be better for an outdoor project. I had half a spool of bog-standard white PLA doing nothing; my wife likes white in the garden because it's easier to find dropped parts; 'nuff said.

Digital Calliper

Useful for checking the measurements of parts that are supposed to fit together. I bought a fairly cheap set but these days I think I would have been better off spending more time researching, and being prepared to pay a bit more if I could ensure better quality (for that reason, I will not name the set I have).

All the design, slice and print steps are pretty much the same: a detailed description is given for the first step, the others follow the same precedure.

As a "proof of principle", the outer perimeter of the proposed mesh was designed and printed, so that it could be compared with the growing plants in the strawberry bed.

• The perimeter wall of the mesh was designed with FreeCAD's sketcher
• The outer radius was set to 105mm - the maximum to allow two to be placed on the print bed
• The inner radius was set to 35mm to allow a reasonable hole for the plant
• The thickness of the perimeter wall was set to 3mm
• Once the sketch was complete ("0 degrees of freedom") it was closed
• The sketch was turned into a 3D model
• The pad tool (in the part-design menu) used to make a 3D object.
• Pad thickness was 3.5mm
• This model was exported as an stl file.
• The model was prepared for printing with Cura
• The stl file was imported into cura
• The model was sliced using my standard PLA parameters
• nozzle: 0.4mm
• layer height 0.2mm
• wall, top & bottom thickness: 0.8mm
• infill 20%
• nozzle temperature: 200C
• build plate temperature: 60C
• no brim or skirt was required
• no support was required
• The generated gcode was saved
• The perimeter wall was printed
• Octoprint was used as the interface to the printer
• OctoPrint runs on a Raspberry Pi that is connected to the printer
• It acts as a web server which is accessed over wi-fi using a browser (I use Chrome)
• The gcode file was dropped onto the OctoPrint printer interface
• The part was printed, taking about 1hr.
• The printed part was compared to the strawberry plants in their bed and the size was deemed reasonable!

The perimeter model could then be used as the base for the support mesh:

• a new sketch was added and a rectangle 2mm wide was drawn to bridge the inner and outer semi circles of the perimeter
• the rectangle was duplicated 6 times (7 in all)
• the rectangles were arranged in a radial pattern and linked to the sketch for the perimeter (in FreeCAD I used "link to external geometry" as the perimeter is a different sketch). I found it useful to add construction lines radiating from the centre and place the rectangles around these
• this sketch was closed and padded to 3mm
• another sketch was added and a semicircular component 2mm wide drawn to link with the straight sections of the perimeter.
• 5 copies were made (6 in all)
• the semicircles were arranges concentrically to complete the mesh
• this sketch was closed and padded to 3mm
• the complete part was exported as an stl file
• the stl file was opened in Cura
• the part was duplicated arranged on the build plate (in Cura)
• the part was saved as gcode
• the gcode file was printed as above

For ease of printing, rectangular cross-section legs were used. The legs were designed with a slot to grip anywhere on the radial bars of the mesh to allow for uneven ground, stones etc.

• 100mm long
• taper from 8mm to 3mm
• the slot in the top is designed to be a tight fit on the radial parts or the mesh
• 2mm at the top
• 2.5 at the base
• 3.7mm deep
• these are quite small and were batch printed by duplication in Cura (I made 6 per full frame)

Each pair of meshes can be linked with bars running between them

• two slots in the bottom of the bars used a similar design to the tops of the legs to give a simple gripping slot.
• parametric modelling makes it easy to change the length of the bar whilst keeping the slots as designed
• bars were printed (6 per full frame) with overall lengths of 12, 25,35 and 45mm
• it would make more sense to base the bar length on the inter-slot distance rather than the overall length, but that's not what I did!
• again, small components easily batch printed

The supports can be assembled in a variety of combinations to suit the plants and beds of your strawberry patch.

Unlooked for bonus 1: The connection bars allow the frames to be linked to each other.

Unlooked for bonus 2: Printed at this size, the disassembled meshes can be stored in a printer filament box.

The final picture shows some strawberries ripening in out garden; not as neat as the advertising pictures for the commercial versions, but hopefully more realistic. (Up here in the Frozen North of England, our strawberries were not ready in time for publishing this Instructable in time to enter the "Home and Garden" Competition, or for eating whilst watching Wimbledon!)