Introduction: ModQuad - Modular Growth Space
Hello Instructables Community!
We are students in 5th and 6th form (11th and 12th grade) - we make up the Makers and Robotics team and work in the FabLab at Saint James School in Hagerstown, MD. ModQuad is our submission to Instructables' Growing Beyond Earth Contest.
The idea behind ModQuad was to create a fully modular, space-efficient system for growing plants, with light being able to reach even shorter plants below the tallest ones, lessening competition amongst plants in the system.
Our final design was able to accomplish these goals, though this project was still quite a prototype. The main structure is made up of hollow pillars and attachment cubes at the corners; all of which were assembled using laser-cut pieces. Autodesk Fusion 360 and 3D-printed components proved to be central to our design process; the tools available to us in our FabLab gave us the ability to create the components we needed and designed during the development of ModQuad.
ModQuad's growing system is made up of two main pipes, which will hold water for the plants. Plants can be grown within removable grow boxes, which are stored in shelving units along each of the pipes (we chose zinnias, as they are edible, rather space-efficient plants that have already been considered as a possible space food source. Other plants could be grown in this system, if preferred). Rather than having to remove all plants in one harvest, each one can be removed individually at any time to harvest it or re-plant. Grow boxes are in offset columns, growing towards the corners of the boxes in order to maximize growth space.
Plants are grown directly facing a fluorescent light bar in order to promote the forward direction of the plants' growth (Facing the source, the strength of the light was 10-12 W/m^2). Efficient use and spread of light was a large goal from the initial stages of development - the system we designed allows light to be reflected by aluminum foil lining on the walls of the main box and on a divider in the middle of the growth space. Light is thus spread throughout the system - even facing the side, the light recovered was about 50% of the original source, or 5-6 W/m^2. This allows for relatively strong light to reach smaller plants as well as providing more area for light absorption, giving the plants' sides access to the light. Fluorescent light ballasts are installed within the hollow pillars of the box in order to save space - and avoid any toasted plants! We chose fluorescents to keep the cost of the project down. In the end, we were able to create a system that met our goals for efficient light usage.
The grow boxes gain their water through planting foam embedded into the pipes at various intervals, which insert into a hole in the grow boxes; plants would be able to transpire to absorb water through these foam pieces; this, however proved to be inefficient as the foam was too rigid and broke quite easily. A new plan would be to use piping as a means of water transfer instead of the foam.
Here we will outline the steps taken to create our design, providing some ideas of what could be improved upon as we go the steps. We hope you enjoy our design!
Supplies
Materials:
1" Center Diameter PVC Pipe (1 5/16" outer)
2x 1" 90 degree PVC joints
2x 1" PVC endcap
2x 1" PVC Screw Valves
3mm Hardboard
Zinnia seeds
3D Printer
Filament
Laser Cutter
Drill (with bit to match screw diameter, other various bits)
Screws
4x GE 18" Full Spectrum Fluorescent Tube Lights
8x T8 Fluorescent Sockets
18 gauge wire
Saws
Small piping
Wood Glue
Hot Glue
Gorilla Clear Glue
Step 1: Prepare Box Structure - Pillars.
For starters, the box is made up of ten 40x5x5 cm pillars and eight 5x5x5 cm cubes at the corner. In order to create these, we utilized MakerCase's basic box generator (available at https://en.makercase.com/#/basicbox). Each of the pillars we used were created using these settings. The finger width can be set to the user's preference. The material we used was 3-mm thick Hardboard paneling, thus we set the material's thickness to 3 mm. Again, if another material is preferred, the material can be set to be thinner or thicker than what we used.
Step 2: Prepare Box Structure - Corner Cubes
Again, using the MakerCase tool, corner cubes can be set up, 5x5x5cm. Material thickness and finger width can again be set to user preference.
Step 3: Laser Cut Cube and Pillar Files, Assemble Pillars and Cubes
Downloading the DXF files for both the pillar and cube from the MakerCase generator, laser-cut the files (10x pillars, 8x cubes). Assemble pillars and cubes, using wood glue and clamps to hold in place while drying. On two of the pillars, drill two holes (one near the top and one near the middle); you will place the ballast within the pillar and route wires as pictured.
Step 4: Assemble Main Box
Assemble the main box structure, attaching the pillars to the cubes at the corners of the box as pictured.
Step 5: Step 5: Measure and Cut the Pipe
Cut out two pieces of PVC Pipe, length 18 in. Create two lines of six holes, spaced 2.5 inches from each other; the rows should be 90 degrees apart. Cap one end of the pipe.
Step 6: Prepare 3D Models: Cornerpieces/light Fixtures.
Each cornerpiece is designed to hold two light sockets as well as be an anchor point for what will later become our central divider (thus, a 3mm wide slit is designed into the cornerpiece). Four corner-pieces are required.
Once 3D files are printed, tap the model with a drill bit that corresponds to the size screw used. The tap hole should be towards the leading edge (as pictured); to get exact dimensions, position of the cornerpiece can be adjusted. Mount sockets, screwing them to the cornerpiece. Mount the cornerpieces at the top and bottom of one corner of the box, and on the top and bottom of the corner across from it. Wire sockets according to ballast, and install lights.
Step 7: Prepare 3D Models: Shelves.
Next, we will prepare the shelves to hold each of the removable grow boxes. 3D Print 12 shelves (6 for each pipe), and stack them on the pipes as pictured, leaving about a quarter inch of space between shelves (this space will be used for lids).
Step 8: Prepare 3D Models: Grow Boxes
Next to print are the removable grow boxes themselves. These pods will hold soil pods with the individual plants in their current state, the boxes are quite short and do not fully hold the soil pods. A change for the next variation would be to either increase the height of the boxes or to use a less tall pod. However, the boxes are still more than functional as they are. Print 24 boxes, which can be installed and uninstalled freely.
Step 9: Prepare 3D Files - Box/Shelf Lids
Lastly, we will print the Lids/Covers for the grow boxes. These will be used to hold the grow boxes and soil in place, and are cantilevered between shelves. Further revision would include a better attachment mechanism (possibly a latch of sorts), as installation and removal of one of these can knock off other lids. They are functional, however. 24 are required for full installation.
Step 10: Install Foam Stops in Pipes
Once shelves are installed, the next step we take is to create planting foam stops to make sure that plants can get their needed water through transpiration, but still stop leaks when individual boxes were removed. We cut out for each slot a piece of planter's foam about 0.4 x 0.5", and about 1". This was to be molded to the shape of the boxes and pipe, and actually worked quite well until we glued them in place (using the Gorilla Heavy Duty Glue), when they became quite brittle and snapped easily; further revisions would likely include a more flexible pipe instead of the foam, simply using the foam as a water-sealant when the plants are not in the shelving unit.
Step 11: Install Grow Boxes and Lids
Once the foam inserts have dried and tested for water-tightness, we can finally install the grow boxes and lids! For each shelf, insert two grow boxes as pictured, positioning the hole in the grow box over the foam inserts; once plants are in place, lids can be installed by placing the tab above the shelf and tightening the gap between it and the shelf above it. This will cantilever the lids, and hold the grow box and soil in place.
Step 12: Install Pipes/Shelving Units in Final Box, Add Valves.
Once the shelving units are prepared, install the valves to be used to feed water into the system. Place a 90 degree elbow at the top of each pipe. Connect this elbow to the valve by cutting a small piece of PVC pipe to be used as a connector. Screw on the cap.
We can now install our shelves! Glue the bottom shelf to the base corner of the box, and attach the top end of the pipe to the top corner, using some planting foam as support. A further revision would probably include creating a 3D model to be used to secure the top end of the pipe better, but this still holds very strongly.
We had already installed the foil around the box at this point, but this made it very difficult to install the shelves as we could not properly reach inside the box, and were only able to access it from the top and bottom. To make this easier on you all, the foil wrap will be our last step.
Step 13: Install Reflective Wrap Around Box, Reflective Divider Across Box.
Lastly, we will install the reflective coating and divider that will allow light to be efficiently diffused around the box.
For the divider, cut a piece of 3mm thick material, 55 x 50 cm. (material type does not matter as it will be coated in aluminum foil - all that matters is that it will fit within the slots in the corner-pieces). Use hot glue to attach foil to both sides of the sheet, ironing it relatively flat. Install the divider, placing it in the slots in the corner-pieces as pictured.
Finally, wrap the box in aluminum, using hot glue to secure the foil on the pillars. A top and bottom layer of foil were needed to cover all of the area.