The following was written by University of Arizona graduate student Atila Meszaros, and lead researcher on Bioregeneration experiments at SAM. Any changes from the original body of text are in [brackets].

We are reaching the end of the second week of our first peas-experiment, still tweaking here and there, but learning pretty much every day. We are developing protocols and knowledge that will help us perfect growing cultivars at SAM for the next few years.

Since the last TODO list, before the experiment, we had 43 different activities to complete, each one with its own ramifications and tasks. But with everyone’s help we managed to pull through and we were able to finish the set up for the experiment. The next runs should be relatively painless from now on [in theory].

  • All monitoring and control for our main systems are wired, programmed, automated, and up and running. Something I will tackle soon, for both my thesis and SAM, is [a compilation of] the physical and computing processes—how I wired everything to each line of code, [including] video tutorials on how to operate Campbell and Logger net.
  • All data is saved in several places, the local computer at the IT room, [our shared SAM] Google Drive, and my personal PC. We are taking measurements every second, I will probably change it to every 10 seconds if the data gets too heavy to process. Just in 10 days we had 8 million data points. A little bit too much but it doesn’t hurt for now.
  • All racks are fully functional and with newly installed devices: extra lights, extra fans, new pumps, water pressure probes. We are reaching around 500 PPFD on our racks. Comparing it with Dr. Wheeler’s and Chinese Lunar Palace, their numbers vary between 400-600 for their highest output crops, and 700 PPFD for wheat. We are in a good range for our PPFD, although I would like to implement the dimmers in the future to have more flexibility. However, this also means that more lights cannot be added unless they are intercanopy lights that go in between the plants.
  • Temperature as we know is our biggest issue now. Hopefully with the recharge of the [failed mini-split unit], this gets solved for the foreseeable future. Our brand-new humidifier system is working perfectly, providing consistent values between the 40-45% relative humidity. We don’t see any reason why it would not provide the same consistency on higher humidities as we move the VPD. All the Whirlpool dehumidifiers have a range between 35%-80% currently setting is 45%. We haven’t seen any algae accumulation in the translucent tubes.
  • The crops seem to be growing strong and healthy. Revisiting the reflective wall experiment, where it took 20 days for us to see the first pea pods, 12 days since the transplanting, we are already seeing some of them in all the racks. One disadvantage of not being able to go inside, is not being able to record events like these every day. The addition of inner-rack cameras could be a possibility that we add in the future.
  • The CO2 injection gave us some problems the first days, as we were figuring out how to properly manage the regulator + CO2 tank. The CO2 tank gauge needs to be completely open, while every pressure change is in the regulator. I know it makes sense as I said it, but we didn’t want to have too much pressure at the beginning, so we half-opened the CO2 tank gauge. [Then] we find out that that CO2 gas output would shut off. Now, the system is working as intended, and we have consistent CO2 injections.
  • Now, on CO2. After some comparison between the SIMOC arrays, Campbell, and the handheld CO2 device. We have concluded that the SIMOC values at the TM are off by approximately 100 ppm. Talking with Ezio he mentioned that the calibration might be off. The numbers are ultimately constant, with the same offset value at different points. I am confident we can just process this post data recollection. I didn’t want to change the offset just yet, in case I was wrong, and it was an error from my devices.
  • The CO2 addition during the time that we go inside the TM is considerable. 20 minutes between Luna and I can increase more than 100 ppm. Every time we go inside, we have a specified agenda that we tackle as fast as possible. Tomorrow, we have a scheduled ingress, and I am thinking about running the blower with extra ports open so when we worked inside the CO2 ppm remains closer to 800, instead of taking longer to stabilize.