Divine Seeds Contest: Auto Opium (and probably my last grow)

Waiting for first signs of life … While we are, I thought I’d give you a short explanation on the software’s graphics in case you did not follow my first diary. The one to the upper left, as its headline says, is the temperature graph. Most important line is the red one, showing the leaf temperature measured with an infrared temperature sensor. As there are no leaves yet, it is pointed towards one of the pot’s wall at soil level. Air temperature from a sensor that usually hangs around somewhere around top level is violet, and the grey line is the outside temperature close to the tent, helping the software to determine if a main blower action will effectively lower temperature. As I learned from the first grow a plant day that corresponds to the natural day can cause enormous gaps both to temperature and humidity, I inverted the plant day now, starting their night at 11 a.m. So after the first day temperature will only vary around 1.5 °C, which is of course due to the low light intensity too. Humidity graph on the upper right is quite crowded. Main line is the blue one, tent air humidity, which on this first day was between excellent 65 – 70% most of the time. For the moment humidifier is electrically disabled. There is quite some excess humidity on the tent floor and no reason to push this any further. Outside air humidity is grey again and taken from the same outside sensor that reports outside temperature. The soil humidity sensors are simple analogue capacitive sensors which have their flaws. I am interpolating their measurements to have a somewhat smoother reading, but as you can see from the turquoise humidifier reservoir reading (in legend named as plant soil hum 1), they can get confused when humidity is very high and start to report random numbers for some time. The most important graph for all growing stages is the lower left one, where the pink line meaning plant VPD should be inside the green optimum range for somewhat perfect conditions. This cannot be attained all of the time – dehumidifying isn’t as easy as humidifying –, but software tries its best to do so. Outside VPD is grey again. The last graph is more for amusement than anything else. The light intensity sensor is hard to position correctly, and everything you see about illumination and DLI (orange and green, plus grey for the accumulated 24 h DLI) should be taken with some spoonful of salt. Any resemblance to real world professional instrument readings can be considered purely coincidental. The violet line is the CO2 reading from such a sensor, and you can see that its tiny peaks correspond to even tinier black peaks at the bottom of the graph, reading TVOC values which in this case, once they will be more than possible measurement irregularities, can be interpreted as smell. ------- End of week 1: All seeds germinated. I wasn’t at home most of the time, and it turned out using the humidity sensor to monitor the humidifier’s tank wasn’t good for the stability of the system. Arduino crashed, so there are no pictures yet and no graphs to show. I have the feeling light was a bit low as the seedlings grew a bit tall, but with lights now up to 20% I guess this problem is fixed. More tomorrow when I have some more data to share. Even more end of week 1 (I extended this week to 9 days as I cannot tell when the seedlings started to show): Lights are at 40%, meaning 40 W in total. No reason to give them new water until next week. As some flies showed up from the BioBizz soil, I added 2 yellow cards. So far, everything in normal ranges. I’ll switch the control to grow phase soon which will raise the VPD slightly by 0.5 kPa. It’s interesting to see the CO2 level started to climb by 50% during their last night and has not come down to baseline afterwards. I restarted the app to check if the sensor had lost its calibration, but it still sits at around 660 ppm now.