I am in the initial wet testing stage for the newest version of the system which is shown below.  I'm just testing a two pod system for now.  There are a few new bits: 

• I'm testing cellulose sponge blocks from Sponge Technology instead of the black reticulated foam, since cellulose is more environmentally friendly.  We'll see if the plants like them.

• I added brackets above the plant holders to stop heavy plants from falling out.  

• I 3D printed a cover for the Raspberry PI and controller so that  they don't get dripped on.

The picture below shows the setup I used for debugging a system crash issue that arose when running one minute spray cycles with the real pump and valve.  It turns out that when you run the pump for 30 seconds every minute, it gets a little warm, draws enough current to overwhelm the power brick, and crashes the Raspberry Pi.  I've got a beefier power brick coming that should solve the problem.

I also added a video of the initial wet testing of the valve on the new system to the files section.

Once everything has run reliably for a few days with no plants in it, I'll plant some new seeds on the top and we'll see how they like the new system.