Introduction: Hydroponics Grow Closet

I wanted to build a hydroponic system that could be put almost anywhere and would continue to operate without constant attention that many systems require. I decided to build it inside a metal cabinet and use Phidgets controllers to automate the process. They can be purchased from The system can be expanded in the future and the software can be controlled from anywhere in the world via WiFi.

Step 1: What You Will Need

There are many different sizes of fans, lights, etc. The size of cutouts will depend on which items you have purchased. I got everything for this instructable from Home Depot, my local hydroponics store and my local Fish store.

Metal storage cabinet: Here are 2 examples

Plastic storage tote

1/2" flex pipe

1/2" 3-way hose barbs

1/2" 3-way pvc connectors

pvc shut off valve

Growing pots

Grow lights

Grow light reflectors

White Appliance epoxy paint

1/2" tubing

Exhaust fan

Exhaust filter

Phidgets SBC

Immersion Probe K-type Thermocouple

PhidgetTemperatureSensor 1-Input

Relative Humidity Sensor

Sensor Cable

pH Lab Electrode

pH/ORP Adapter

Dual Relay Board

Digital Timers

SBC WiFi adapter

1/4" tubing

Air stones

Air pump

Pond pump

Light risers

Eye bolts

Exhaust port cover

Dryer vent ducting

Air circulating fan

Step 2: Cabinet

Good light is important in any hydroponic system. I decided to paint the inside of the cabinet with white appliance paint. Make sure to mask off any area you don't want painted. You may choose to paint the whole cabinet, or just the area where the plants need light.

Step 3: Exhaust Fan and Filter

I put the exhaust fan in the top left corner (facing cabinet). make sure to leave enough room to mount the fan inside cabinet. Start by drilling a hole for the exhaust cover. My cover, fan and filter are 4". Using this as a template drill the 4 mounting holes and finish mounting the cover. Line up the exhaust fan with the cover you just installed, drill the 4 mounting holes and mount fan. Make sure that the air is blowing towards the outside of the cabinet. Install the dryer vent tubing between the cover and fan. Use metal clamps to hold it in place. Mount the filter onto the fan.

Step 4: Lights

I used 3 200 W fluorescent grow lights in my cabinet. You may use fewer bulbs if you wish to of the same wattage or more wattage per bulb. Talk to your local hydroponics professional to determine the best set up for your needs. Measure between the light fixture hooks and from the hook to the edge of fixture. Determine the dimensions for mounting lights in center of cabinet. Drill holes to match your eye bolts, then mount the bolts. Hang the light risers from these bolts, then hang your lights from the light risers. You are now able to raise and lower your light as needed. Your local professional will help with these risers.

Step 5: Digital Timers

I used 2 digital timers for this instructable. They can be operated independently from each other. I decided not to switch any high voltages. But this meant that I had to add 2 wires to each digital timer.

Start by removing all the screws from the back of the timer using a Phillips screw driver. There is one screw which cannot be taken out normally. I found it possible to remove this screw using a small Phillips screw driver by just twisting the screw out from each side of the screw. Look at it with a flashlight to see what I mean. This can be done without removing the circuit board. The picture shows a hole I drilled in the circuit board for the wires I added, but don't think this has to be done. Solder one wire to each point as shown in photo. Drill a hole beside power button and feed your wires through hole. Make sure not to interfere with slot in circuit board. Put back on and replace screws. Just leave out the one different screw.

Step 6: Reservoir and Pots

Plastic totes are readily available. You just need to decide on the size you will need for your system. Mine has enough room for 8 three inch pots. Drill holes the proper size for the pots you are using and evenly spaced apart. Center a 3 way hose barb on each pot and connect them together on the sides of tote using flex tubing. Using a 90 degree hose barb with pipe thread on one end, connect each end to a 3 way pvc connector as shown in photo. On the bottom of one of the pvc connectors is a hose barb to connect to pond pump. The other side has a valve for draining the water. Exactly which pieces you will need depends on the particular configuration you are using. Place air stones and pump at bottom. Connect 1/4" tubing to air stones and run tube out of tote to air pump. Connect 1/2" tubing from pump to hose barb at top of lid. Attach Thermocouple and pH electrode to the side and inside of tote so they sit in the water.

Step 7: ​Electronics

I mounted the electronics on the back side of cabinet except for the temperature board and humidity sensor which mounts inside cabinet. The temperature probe and pH electrode are mounted inside tote. The wires coming out of the digital timers need to be connected to the relay board. One wire to the middle and the other to the NO of each relay. The 0 input needs to have a wire connected to digital output 0 and the 1 input needs to have a wire connected to digital output 1 of the SBC. The Humidity sensor needs to be connected to an analog cable then plugged into analog sensor 0 on SBC. The Thermocouple plugs into the temperature sensor board, then this board connect to the SBC via USB cable. The Humidity sensor plugs into sensor input 1 on SBC. You will need to drill a hole for cables and plugs to reach electronics at back of cabinet. Plug in lights to switched side of one timer. The pump to the other switched timer. All other plugs can be permanently on. The circulation fan can sit on shelf and be rotated in the desired direction.

Step 8: Conclusion

This system will work like it is right now using the digital timers to control the lights. I would like ideas of what could be added to the system or what the software should do for future updates. The only thing left is to add water and nutrients to the tote, then adjust pH. Again, ask your local professional about what the best settings should be for the plants you want to grow. At the bottom of this cabinet there is room to start seedlings. Just put a shelf above container with a small grow light below it. After plants start to grow, transplant them to the main system above.

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