Hi !

It has been a while that I'm curious about hydroponics so I decided to create a project to give it a try. This instructable is about my journey in hydroponic.

It is also my first instructable so I'll try to make it clear but do not hesitate to ask questions, I'll do my best to answer.

This instructable is also an entry to the gardening contest, so if you like it please vote for it :)

****DISCLAIMER****** I am really not a professional gardener so i feel free to try things. And sometimes it fails :) but don't worry so far everything works ;)

Ok let's begin.

My goal is to try hydroponic on a small scale, and eventually be able to scale up to grow a few vegetables if the experiment is a success.

It means :

I want a modular system, being able to grow with my knowledge (pun intended).

It has to be on the cheap side, so it wouldn't be too sad if the experiment is a failure.

I also wanted to be able to put it on my desk to check it often.

And finally I decided to use 3d printing because I am used to work with this technique and I had a few neat features in mind that would be easy to do with a 3d printer.

Step 1: Step 1 : What You Will Need

-A 3D printer (fdm) with a minimum printing volume of :180*180*140mm

- A DC motor diameter 24.5mm shaft 2mm

- a power source for your motor (probably 5 or 12V)

- tubing internal diameter 6mm external 10mm

-Growing media (more on this later)

-Growing solution (more on this later)

-4 small m2 6mm long screws

- Probably a hot glue gun

Step 2: Tower Design

There are several ways to do hydroponics out there.

I decided to go for a sort of nutrient film technique (https://en.wikipedia.org/wiki/Hydroponics#Static_solution_culture) because i felt it wouldn't take to much space on my desk.

I based my design on a system that would allow all my components to fit in each other.

The main component is the "module" . It has 3 spot where you can put a basket ("panier") with a plant. You can fit as many module as you want in your tower. The baskets will be in staggered rows. (see pictures)

The nutrient solution flow from top to bottom, through the basket, thanks to a pump at the bottom. Channels are made on the wall to allow a better repartition of the nutrient.

At the bottom you can either fit a funnel ("fond") to fill a random container with a pump or a printed container (" bac reservoir pompe") with printed pump ("support moteur" and ""helice"). I use this option to put it on my desk.

At the top there is the a part ("couvercle") that splits the water flow in 3 streams over the baskets with internal channels.You can also use this part to hang the tower.

Printing the parts :

-All the parts prints well without supports.

-I use PLA to print this because it is food safe. I wouldn't use ABS if you want to eat what you grow.

-If you print the bottom container it has to be water tight. So print with 4 to 6 layers on the side and bottom.

Step 3: Step 3 : Pump

I spent quite a long time trying to figure out how to pump the water in my system.

At first I wanted to use a solenoid pump I salvaged from a coffee machine. I didn't choose this one at the end because it couldn't be immersed and I was afraid it would be quite noisy.

For a production system I think I would go for an inexpensive pump for aquarium, which can be immersed and are quite cheap (less than 20€). Like this one :

https://www.amazon.fr/Yorbay-CHJ-500-Pompe-Aquariu...

However for my first setup I decided to 3d print the pump and use a simple DC electric motor.

I did that because I think it is cool to 3d print a pump, and I had a few electric motor laying around so it was the quickest.

The design of the pump is very simple, it is basically an helix into an enclosure. I didn't made any calculation but i made a few iteration to arrive at something good enough. There are plenty a stand alone 3d printed pump on thingiverse if you want to use the funnel and still use a 3d printed pump.

I use a old power source from an unknow device which is around 9V

If you use the printed reservoir you will have to make the connection between the motor holder and the reservoir watertight. I used a hot glue gun on the seam between the parts, after screwing them together, because I had a little warping on the corners.

Step 4: Step 4 : Assembly

Once you have all the part you need let's assemble !

********If you use the printed reservoir and pump *************

-Start with the pump, push the motor axle through the motor holder hole. Push the helix to the axle of the motor. Screw this assembly to the reservoir with 4 little screws in the little holes. Plug your motor to see if it spins freely, if so use a hot glue gun to cover the seam between the parts.Otherwise find out why it doesn't spin.

-Cut the tubing at the length you need (depends on how many modules you plan to use. Length = Nb modules * 13cm). Put one end on the output of the pump, secure either with hot glue or with a little plastic hoseclamp (there is a little hole for this purpose).

**********If you use the funnel ***************

-Cut the tubing long enough to reach your reservoir at the bottom end and the top of your tower at the other end.

**********For both version*****************

- Assemble your modules and bottom.

-Pass the tubing through the modules all the way to the top. If you use the funnel the tubing should pass through the funnel.

-Push the top end of the tubing through the hole of the top part.

-Put some water in your reservoir

-Plug your pump and watch it rain :)

-You can then put your growing media in your baskets and the baskets in the modules.

Step 5: Step 4 : Hydroponics

With hydroponic your plants will grow on a growing media thanks to the nutrients contains in the nutrient solution.
There are plenty of alternatives for both. Here is the wiki link for substrates : https://en.wikipedia.org/wiki/Hydroponics#Substra...

For my test setup I am currently using glass wool which is probably not the best choice, but i had it around so I gave it a try. I would probably go for rock wool for production. Anyway you can choose anything as long as it doesn't disintegrate, or it is big enough to be held by the baskets. Otherwise there is a risk to jam the pump.

For the nutrient solution I decided to use Bokashi juice (anaerobic compost), because I could have if for free. Here is an article explaining what is Bokashi and how to use it with hydroponics:

https://www.hydroponic-urban-gardening.com/hydropo...

There is loads of information online, and sometimes quite technical. I won't say more as I am not an expert and my experiment is still too young to draw conclusions.

Step 6: Step 6 : Growing

You can start experimenting !

Please share what you did and if it works or not.:)

For my first try I used a few seeds a had laying around (tomatoes, basil, coriander, pepper) and dropped a few seeds in each basket filled with glass wool that have been wetted (the glass wool seems to be repellent until you soak it, then it keeps water quite easily).

I then plug the motor 15min in the morning and 15 min in the evening and everything stays wet.

I don't run it continuously because it is a bit noisy on my desk and I am not sure the motor can handle continuous operation for long.

I started this experiment 2 weeks ago and the seeds are starting to grow. Time will say if they can grow healthy...

The next step is to automate this with an microcontroller.

Step 7: Step 7 : Automation (optionnal and Still Work in Progress)

*******It is still work in progress****************

As i said right now my setup isn't automated, I just plug twice a day the tower for 15min and it seems to be enough.

Anyway at the beginning of the project I thought I would need to automate this to start the pump regularly so I made a little bit a code for a microcontroller. It is a simple timer that starts the pump for 15min, stops it for 15min, and so on. It uses a a transistor NPN to control the pump.

You will need to download the SimpleTimer librairy.

https://playground.arduino.cc/Code/SimpleTimer/

It is a very (too) simple setup, and the use of the transistor seemed to slow down the pump.

For the next version I will probably use a Wemos D1 card which has wifi and use Blynk (

https://blynk.io/) to create a simple interface on my phone. I'll keep you posted for this.