Aeroponics Phase 1

Table of contents for Aeroponics

Now that we are done with the reverse osmosis system that is designed to filter our rain water, we have to come up with some uses for that water. We plan to use the filtered rain water for our fish tanks and an aeroponics system that will grow herbs and vegetables.

The basic concept of the aeroponics system is that the plants grow in air not in soil or water. A nutrient water solution is sprayed on them, but the majority of the time the plants are hanging mid air with no water being present. In order to get the water to the roots a fogger or sprayer unit is needed. Both these systems must be capable of getting the water into small enough droplet sizes that the water is almost instantly absorbed by the plants. In order to accomplish this, we chose to go with a fogger unit because we have heard that sprayer units accumulate minerals on the tip and eventually become irreparably clogged.

One of the key features of a true aeroponics system is droplet size of the mist being used to deliver water and nutrients to the plants. Water droplet sizes between 5 and 50 microns in size are ideal. Larger droplets are unable to deliver enough moisture and nutrients and smaller droplets cause excessive root hair to develop thus detracting from leaf and fruit production.

More infos here and here and here. You may notice in that final video that the root systems did not seem to be light-isolated, that is, their roots were exposed to the grow lights. This leads us to believe that dark root chambers are not strictly necessary. Time will tell. We’ll be testing out this, and many other variables in our research. Also there is another person experimenting with aeroponics that we would like to mention: kellbot.

We purchased two of the cheapest fogger units we could find to test things out. We hope to tear one apart and reverse engineer it and use the other for the aeroponics system. Here is a video of the working fogger unit. This is just a demonstration so that you can see how much fog it is going to produce.

Fogger Test from crackchihuahua on Vimeo.

You’ll notice that there was a small amount of fog coming out of this unit in the video. We found that when keeping the unit 3″ under the surface as recommended in the documentation, this is the amount it would produce. However, when we got all crazy with it and moved the unit closer to the surface of the water, we found that it produced substantially more fog. At least 4 or 5 times the amount. Needless to say, we will be voiding our warranty on this one and operating the units close to the surface to maximize fog production.

These are cheap, $20, fogger units designed for use in small fountains which is why it has that stupid red LED on it. The “professional” aeroponics foggers can cost hundreds of dollars each and do the same thing though they do output more fog. In all our research we were unable to find documentation stating categorically that the “professional” units did anything different than these cheap units. Both are subject to mineral buildup that needs to be periodically cleaned off the small transducers and both produce droplets around 5 microns in size. Incidentally, we would really love a way to measure droplet size so if any of you smart people out there have a simple way, tell us about it!

We are configuring a good layout for getting the fog to the plants. We know that we will need some sort of fan to move the fog out of the fog chamber. We suspect that we can use a waterproof fan made for cooling computers to do this. We also think that we can use some sort of large, dryer type, hose to channel the fog from the fog chamber to the plant chamber. We plan on using some sort of large plastic container for the plant chamber and maybe a smaller one for the fog chamber.

For future expansion, it would be best if the hoses were removable. This way we could attach the fogger unit to the other plant chambers and expand our growing ability. Maybe even automate it! We’re thinking one central fogger hose that can be hooked to multiple root chambers in turn to supply the needed fog.

To deliver the fog to the root chamber we’ve found a waterproof computer case fan–that’s what it says–from newegg. We will use this to either suck or push the fog from the fogging chamber into the root chamber once enough of a head has built up. Since the roots only need to be fogged for something like 30 seconds

We also did some research on the types of lights that would be necessary to grow plants indoors. For a long time we were under the assumption that plants need UV light to grow, but this is not the case at all. Plants need light in the blue and red light range. We also discovered the red wavelengths of light produce greater crop yields, while the blue wavelengths promoted more leafy growth. You can check out a book on that here.

That’s it for this week,

P&S