It has been two weeks since my last post. A lot has happened with the project since then, but even more has happened in my personal life. I have been too busy to post because my son was born 11/9! He surprised us by coming about a month early, but I had most of the physical build and automation done before then, so I was able to just plant and watch them grow. The only part I have not completed at this point is the wireless communications and web based monitoring and control.
For this blog post, I will give an update on the plants I have growing, and explain the 2nd grow area I just completed.
I planted these seeds and put them in the germination section on 10/20. Here they are on 10/28 :
The germination rate was 100%, but the timing was off by severaly days. Ideally all of the seeds should germinate at once and sooner than they did. I determined that this problem was due to uneven heating of the germination section from the heat from the lights on the level below. You can see in the picture that the seedlings on the outside were more developed than those in the middle. The middle was just too warm for lettuce germination. This will have to be corrected for future plantings. For now, the result was not ideal, but acceptable.
The most developed seedlings were transferred to the main growing area on 10/30. Here are a few pictures showing their development.
11/3:
11/12:
11/15:
11/21: Here is the lettuce today ready for a partial harvest! I will be picking some tomorrow for a salad.
In addition to this, I finished the second growing section and transferred seedlings to it as well. The second section is a test of the growing technique that I think will work better in the long run but is more difficult to implement: low-pressure aeroponics. This section consists of a pump connected to a PVC manifold with small spray heads attached. This manifold sprays the nutrient solution on the roots of the plants which are suspended above. For the top part that is holding the plants, I used a sheet of 1/8” thick HDPE. I drilled holes in the sheet, placed netpots in the holes, and then placed the seedlings in the netpots. This has worked pretty well so far with some minor issues. Here are some pictures:
First Planting 11/11:
Today 11/21:
As you may be able to tell from these pictures, I had a few issues with the aeroponics. For one, the sprayers did not produce as powerful a mist as I expected. Some of them produced really large drops, some only sprayed in one direction, and some hardly worked at all. I think this is probably due to a combination of three factors: the pump needs to be larger, the hole I drilled for the misters was not perfectly sized, and the misters are of low quality.
The result of this problem was that 7 out of 32 plants got so little water that they either died or had stunted growth. These plants we removed and/or trimmed, and I readjusted the sprayer orientation and schedule. The sprayers are now on for 10 minutes and off for 20. I also replaced three dead lettuces with strawberry plants from the garden which is now closed for the winter. I want to experiment with indoor strawberries because I miss them so much in the winter and you can really get nothing comparable in the store to homegrown strawberries.
I also have made progress on my wireless communications to the hydroponics system. I have programmed the EZR32WG kits to basically act as serial to 915MHz converters. My BeagleBone Black is now talking to the Arduino running the show through the 915MHz link. I still have to write the code for the BBB to process the data from the hydroponics system and send commands. I'm off to work on this now!
That's all I've got for this update. I will post another short one when I have my first harvest, and one more after that when I hopefully have everything working.
If you guys have any questions please post below!
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