I posted two photos of the current setup. Thanks to the esp8266 sketch I noticed that the plants were getting far too hot so I adjusted by opening the window during the day. This dropped the temperature down by 5 degree's from 30 to around 25-26 degrees.

Compare this to the red/orange plant tray. The lettuce in that container died as a result of being too hot during the day which likely promoted fungal growth/root rot.

I've also eliminated the use of the clear plastic tray covers to try to avoid containing heat within the planters.

If this batch goes well, I should have edible lettuce in approximately six weeks.

Which brings me to my plans for a few revisions to Phase II:
- Add a gold-plated capacitive soil moisture probe to the agi-esp8266 prototype (Looking at DFRobot for that)
- Integrate a water reservoir to both cool the plant soil in the hot sun during the day as well as water the plants.
- Integrate Homie-ESP8266 with contributions to the project for the various plant sensors OR integrating Arduino OTA updates and a default wireless AP mode for configuring the esp8266 uC.

In the final setup in the desired arctic window conditions, a reservoir would likely serve the opposite effect of warming the soil by getting the plants up to room temperature and/or passively warming the soil by using bleedoff heat from a nearby heated air vent or a nearby radiator. Keeping the soil warm will likely be more effective than attempting to warm the entire plant from residual air temperature. An actual implemented system down the road will be the ultimate test of that. So, that will likely be a testing parameter for Phase III.