Vertical Hydroponic System

This project is a compact, vertical hydroponic system designed to grow fresh produce indoors, using no soil, minimal water, and very little maintenance. Built with a mix of off-the-shelf trays, a custom-welded metal frame, and basic electronics. A very efficient way to grow plants.

But beyond growing food, this project also supports a more sustainable way of farming:

1. Doesn't degrade or erode soil - No soil means no erosion, compaction, or nutrient depletion.
2. Uses far less water - A closed-loop system recirculates water efficiently, cutting down consumption drastically.
3. Reduces the need for pesticides and herbicides - A controlled environment minimizes pests and disease naturally.
4. Is more efficient with space (2D for traditional ; 3D for vertical farming)
5. Even monocropping (growing only one type of plant) - which usually damages the ecosystem, and depletes if of all nutrients. The environment within this system could easily be controlled.

This setup can also be scalable and reusable. Making it is a Long-lasting solution with minimal environmental impact.

Frame & Structure

1. Steel square tubing (for custom frame)
2. Welding machine (or metal brackets if not welding)
3. Caster wheels (4x, preferably locking)
4. Screws & drill
5. Or off-the-shelf shelf rack

Grow Trays

1. Off-the-shelf plastic storage trays (3 or more)
2. Tray lids (or custom-cut covers)
3. Net pots
4. Hole saw (for drilling net pot holes)
5. PVC pipe & fittings (for water inlet/overflow)
6. Silicone sealant (to waterproof trays)
7. PTFE tape

Lighting & Electronics

1. LED grow lights (either panel or strips)
2. Mechanical timer
3. Power strip
4. Submersible water pump
5. Electrical enclosure box
6. Wires, connectors
7. Optional: reflective insulation roll

Water & Nutrients

1. Reservoir container (for water and nutrients)
2. Part A & Part B hydroponic nutrients
3. pH meter
4. Small filter (mesh pre-filter for pump)

Planting

1. Seeds (lettuce or other leafy greens)
2. Sponge
3. Germination tray or shallow container
4. Spray bottle (for keeping seedlings moist)

Before starting this project, I honestly had no idea what hydroponics was, or much about growing plants without soil at all. So I had to do quite a bit of research into the different hydroponic methods and the types of technology typically used in systems like this.

After going through a few rough sketches and eventually putting together a CAD design, I felt pretty satisfied with the layout and structure I had planned. Unfortunately, somewhere along the way, I ended up losing both the sketches and the CAD file. :/

For this build, I custom-built the frame using welded metal beams to get a snug fit for the grow trays. While you can definitely use an off-the-shelf shelving rack. I welded the metal pieces together to form the structure and screwed in caster wheels to the bottom so the entire system can be moved around easily. Ensure the frame is level and sturdy enough to hold the weight of all the grow trays, water, lights, etc.

💡 Optional: You can paint the frame or leave it bare metal, depending on your preference. Just make sure to smooth any sharp edges after welding. 👍

For the grow trays, I used off-the-shelf plastic trays, customizing them to function as hydroponic grow trays. First, I drilled evenly spaced holes on the lids to hold the net pots. ensuring that the spacing wouldn't cause overcrowding when the plants grew. A hole saw attached to a drill worked great for this.

In addition to cutting the wholes for the pots, I also cut holes on the lid and at the bottom of the tray for PVC pipe that would act as overflow outlets and water delivery inlets. (You'll see what I mean in step 5).

Then, afterwards, the inner edges and seams of the trays were sealed with silicone, making them fully water-tight. This is important as a lot of off-the-shelf trays weren't originally designed for holding water for long periods of time and could develop leaks.

💡 Make sure to test each tray for leaks before installing it in the full system.

To power the system and keep everything running smoothly, I built a simple electrical control box that handles the grow lights and water pump. It's housed in a plastic enclosure to keep things neat and protected from splashes.

Inside the box, I installed:

1. A mechanical timer to control when the lights and pump turn on and off
2. Multiple power sockets are wired in for the pump and lights

For the lighting, I mounted LED grow lights directly above each grow tray level. They’re plugged into the control box and connected to the timer. I usually keep the lights on for about 14–16 hours per day, which seems to work great for leafy greens like lettuce. But also sometimes for 24 hours a day for an extended period of time, where it still works perfectly fine.

💡Optional: I added some reflective & insulating roll for better lighting efficiency and coverage, as well as for aesthetics.😊

Water enters the top tray from the pump at the very bottom. Each tray has its own overflow pipe allowing excess water to pass through to the next tray below, keeping the water level consistent without over flooding in any one tray and also optimal water level for the roots of the plants. The roots of the plants in the net pots hang down into the nutrient-rich solution, where they can continuously absorb water and nutrients as it flows through the system.

At the bottom tray, any remaining water exits through its overflow pipe, where the water returns to the reservoir, ready to be pumped back up again in a closed-loop system.

In this reservoir, a submersible pump pushes the water back to the top tray, passing through a simple filter to catch debris. Even when running it for weeks on end, the system has been so cleaned, there was nothing to catch.

This passive overflow system helps balance water levels automatically across all the trays and is very low-maintenance.

💡If the PVC overflow pipes are not fit enough and leak externally, you can use silicone to seal them up, or PTFE tape.

To start, I filled the reservoir with tap water and let it sit for a few days. This allows any chlorine in the water to naturally evaporate, which is important because chlorine can harm the roots and beneficial microbes in the system.

Once the water was ready, mix in Part A and Part B nutrient solutions, following the recommended dosage on the bottle. These typically contain all the essential macro and micronutrients needed for healthy plant growth in hydroponics. Since I would be growing leafy greens, I adjusted the pH accordingly to around 5.5-6.0.

To start the growing process, I germinated the seeds in moist foam I cut into grids, placed on top of a moist growing mat, in this case, just a tray I had lying around. The tray stays damp and also provides a clean surface for the seed to sprout. It's quite interesting to see seeds sprout without soil. Within a few days, the seed develops small roots and cotyledons.

Once they grew a bit larger, usually when the roots were long enough to poke through the foam. I transferred each plant and its piece of foam into net pots. It's important that the roots are able to freely hang and long enough to reach the flowing nutrient solution.

Once everything is running, the system mostly takes care of itself, but a little regular monitoring is quite useful. Plus, I just like to catch a glimpse of the system running and the plants growing, because it just looks so cool to me. I usually do a weekly check-up on the water levels and pH levels.

For water levels, every week the water level will go down in the reservoir due to plants using it, and also some evaporation. So just add a bit of water to the reservoir. If you use a bigger container for the reservoir, you can easily get away with not having to add water to the system for much longer periods of time. But I went for a quite small container.

As for the pH levels, I mainly use it as an indicator of when to add more of the nutrient solutions. As well as keeping an eye on the plants themselves to see signs that something might be off, such as yellowing of the leaves.

This vertical hydroponic system turned out to be super clean, space-efficient, and very low-maintenance to grow fresh produce at home. Of course, I have a few things I would change if I came back to working on this project. Given more time, I'd definitely look into incorporating more automation and electronics. Things like automatic pH regulation, water temperature control, EC monitoring, etc. In addition to collecting more data about the plants growing using this system and comparing it with more traditional methods.

As well as exploring new ideas for this, such as increasing the CO2 concentration to see how it could affect plant growth. Cause I heard from someone (not sure if this is true), but it could make the plants grow a lot faster, as well as making them taste a bit sweeter.

Still, even in its current form, the system works amazingly and is definitely a conversation starter whenever someone comes into my room. It uses minimal water, no soil, and actually helped my lettuce grow faster than expected, from seed to plate in just about three weeks.