Starting things simple I wanted to try the concept and get a feel for the feasibility. This setup consists of one T-junction of 10mm diameter plastic piping, normally used for plumbing.
Holding the plant (cauliflower) is a 3D printed part, partly filled with perlite. The plant itself is seeted in a little bit of earth. I first tried to germinate the seeds in continuously moist earth, in the setup, but that was not a success. Germinating in a little more dry earth worked much better.
The figure below shows the small setup I have right now (yes I did say I wasn't going to use an Arduino, but I am still waiting on my nodemcu V2 esp8266 board). The lamp is a 25 W UV light used for terrariums and has the right spectral properties for growing plants (In the future I might move to LED's though). Everything is placed on a plastic container that holds the nutrient.
Not the intended ebb and flow method either. The valve I bought needs a delta pressure of 0.8 bars so nothing dripped trough on this very small usecase. So now, the pump is activated every thirty minutes for 5 seconds. When moving to the esp module I want to be able to remotely change the timings for both the pump and the light. More on that next time.
As mentioned before, the part I used has been 3D printed. The part has been printed in two pieces (so it is 2 parts?) in PLA. Not the ideal material, but it is what was available, we'll see how long it lasts.
I started out with a 6 V pump, which could then easily be actuated from the same supply as the controller. In the top of the plant holder I placed a ring of tubing with holes to evenly distribute the nutrient arount the plant base.
However, the holes were too small, or not enough of them, causing too much resistance of the pump and after three days I had to say goodbye.
With my sights set on the future, I removed the ring, and replaced the pump with a more powerfull aquarium pump. This seems to be a better fit and should be able to stay with me when upgrading to a bigger 'farm'.