Vertical Hydroponic Tower Array

My design incorporates a combination of 3D-printed parts and off-the-shelf components to create a watertight system of modular towers for use in a greenhouse. Key features of my design include:

1. Compact footprint: Minimizes space usage and reduces light obstruction to other garden plants in the greenhouse.
2. Thermal stability: Provides a large thermal mass to release heat slowly during cold nights and cool the greenhouse during hot days.
3. Passive cooling: Takes advantage of aluminum's conductivity and water evaporation to maintain lower daytime temperatures.
4. Sunlight blocking: Prevents sunlight from entering the tower's interior, reducing algae growth.
5. Modularity and easy maintenance: Designed for straightforward cleaning and customization.
6. Durability: Withstands high summer temperatures without melting.
7. Use of off-the-shelf components: Keeps costs manageable and simplifies sourcing parts.

In the supply list below, I’ve included links to my free models, which are also available for download on Printables via my maker profile.

Additionally, I’ve redesigned many components to enhance functionality. These new designs offer:

1. Improved root health: Controls water flow over roots to reduce root rot and improve oxygenation.
2. Enhanced sealing: Eliminates the risk of roots growing between silicone and 3D-printed parts, preventing seal failures and algae growth.
3. Precise alignment: Includes an alignment tab to perfectly center the netpot holder in the downspout cutout.

See below links for the upgraded versions:

V2.0- Netpot Mount

V2.0- Diverter

3D Printed Components

1. 4x netpot holders per 24" of downspout
2. 1x diverter per 24" of downspout
3. 2x brackets per 24" of downspout
4. 1x barbed connector per tower
5. 1x pipe hanger per tower
6. 1x cap per tower
7. 1x outlet per tower
8. 1x drain support bracket per tower

Recommended tools

1. Drill
2. Tin snips
3. 3D printer/PLA or other type of UV resistant, stable filament
4. Pipe Threader (3/4" NPT threader)
5. Disposable gloves
6. Wire brush
7. Metal File

Commercial off the shelf components (source at local hardware store and or aquarium supply store)

1. Clear exterior rated silicone caulk (waterproof, UV resistant)
2. 4x wood screws per bracket
3. Pond pump (select based on desired volume flow and lift capacity, recommend this pump for this tutorial).
4. Aquarium Aerator appropriate for tank size
5. 1/2" flexible irrigation tubing (recommended)
6. 3/4" Black steel schedule 40 Pipe
7. 3/4" Galvanized Iron Cap Fitting
8. Barbed Connector between irrigation tubing and Pipe
9. 2"x3" Aluminum Downspouts
10. Vinyl Downspout Connectors

This design is intended for mounting onto a 3" x 4" gutter downspout. To install it, follow these steps:

1. Prepare the cutouts:
2. Mark two rectangular cutouts (1.5" x 2.5") on the downspout, ensuring a minimum spacing of 3.5" between them for sufficient clearance between each netpot holder (refer to the provided image for details).
3. Measure 1.75" from the top front and bottom back of the downspout to allow space for a downspout connector and mounting bracket.
4. Cut and prepare the downspout:
5. Cut the 2" x 3" aluminum downspout to your desired length.
6. Using the provided dimensions, mark the cutout areas on the downspout. (Click the image to reveal hidden dimensions.)
7. Use tin snips to carefully cut out the rectangles.
8. Flatten any ridges or burrs caused by cutting to ensure a smooth surface.
9. Prepare for mounting:
10. Use a wire brush to remove the exterior coating around the cutouts. This step is critical to ensure a clean surface for adhering the silicone to the netpot holders.

I live in the southwestern United States, where summer temperatures often exceed 98°F with little to no cloud cover. Nighttime temperatures can plummet, and the intense daytime heat poses risks like heat stroke. I've had plastics left on the top shelf of my greenhouse become distorted or partially melted due to these harsh conditions.

Given this environment, I chose 3/4" galvanized pipe for its durability and resistance to plastic leaching under extreme heat. It also ensures watertight connections and helps maintain a level system, which evenly distributes water.

Installation Steps:

1. Prepare the pipe:
2. Mark the pipe to align with the studs you will mount the towers to.
3. Use a file to slightly flatten the tangent edge of your marks.
4. Drill a hole using a 1/8" drill bit, ensuring the hole goes through only one side of the pipe. (Optionally, use metal-cutting lubricant to keep the drill bit cool and ensure clean cuts.)
5. Thread and clean the pipe:
6. Thread both ends of the pipe.
7. After threading and drilling, wash the pipe thoroughly to remove any lubricant or debris.
8. Assemble the connections:
9. Cap one end of the pipe with a galvanized steel cap.
10. Slide the barbed connectors onto the pipe, aligning their through-holes with the drilled holes. Use a watertight sealant or bonding material to ensure the connections are leak-proof when pressurized.
11. Screw the barbed connector onto the other end of the pipe.
12. Mount the system:
13. Attach hanger brackets to the studs as shown in the images. Ensure the pipe is properly spaced from the studs for stability and functionality.

This outlet is connected at the bottom of the tower. It connects the tower to your drain canal that runs back to the nutrient tank. Print this part with the wide opening face up. This was designed based off a 2 in. x 3 in. White Vinyl Downspout Connector, so the connection will be very tight and will require you to bend in the corners of the aluminum downspout to fit properly. 

For installation, you should cut a 1.5in x 1.5in hole in your drain canal (seam side) to allow for installation tolerance and an easy fit. The flange on the bottom of the outlet funnel does not have to be caulked or mounted to the drainage canal. If you do not mount it to the drainage canal (horizontal blue extrusion in images), you can adjust the canal to a custom angle depending on how many towers you have to allow the nutrients to gravity feed back into the nutrient tank.

I used a 2" hole saw to cut several holes in the seam side of the drain canal to create a horizontal hydroponic setup.

I recommend wearing disposable gloves for this step, as silicone is sticky, sets quickly, and can be messy to work with.

Instructions:

1. Apply a thick bead of silicone to the flat surface of the 3D-printed part.
2. Align the oval opening of the part with the rectangular cutout on the downspout. Press the holder firmly against the downspout.
3. If enough silicone is applied, it should fill the gaps and squeeze out around the edges.
4. Smooth the excess silicone around the netpot holder using your finger to ensure a watertight seal.
5. Allow the silicone to fully cure on one side of the downspout before repeating the process on the opposite side.
6. Repeat these steps for all sections.

Once all sections have cured, you can assemble the tower. The following steps outline how to assemble a three-section tower from top to bottom.

Assembly Instructions

1. Install Diverters:
2. Place a diverter inside a 2" x 3" white vinyl downspout connector at the start of each section.
3. Ensure the diverter's flat side faces downward and mates with the ridge inside the connector. (Refer to the cross-section image for reference.)
4. The diverter splits the water into two equal streams cascading onto the netpots. Ensure the tower is level—uneven streams indicate improper leveling, which may deprive plants of nutrients.
5. Assemble the First Section:
6. Press the vinyl downspout connector into the top of the first downspout section.
7. Seat the diverter firmly into the ridge inside the connector.
8. Place a cap on top of the downspout connector.
9. Slide a tower bracket just below the vinyl connector, aligning its top with the top of the downspout.
10. Secure the bracket with 2 screws, attaching it to both the downspout and the vinyl connector.
11. Position the bracket over a stud, centering it with the stud.
12. Align the cap with the barbed connectors and screw the bracket into the stud.
13. Assemble the Middle Section:
14. Repeat steps 1, 2, 4, 5, and 6 for the middle section.
15. Firmly press the middle section's downspout connector onto the first section’s outlet. (You may need to bend the corners slightly; this step can be challenging.)
16. Once seated, screw the middle section's bracket into the stud.
17. Assemble the Final Section:
18. Repeat the above steps for the final section.
19. After securing the final section, apply a layer of silicone caulk to the inside of the outlet described in Step 3, Drain Cutouts to create a watertight seal and prevent nutrient leakage.
20. Once the caulk has cured, slide the downspout outlet part over the third section’s opening.
21. Complete the Tower:
22. Align all towers and mate the downspout outlet to the cutouts made in Step 3, Drain Cutouts.
23. Use a drain support bracket to secure the drain at the desired angle.
24. Connect the drain to the nutrient tank to establish a feedback loop.