So I’m starting out trying to grow vegies indoors (and out) all year round.

Hoping to start out with soil for seedlings and move up to a more hybrid perlite hydro and maybe later consider full hydro.

I started with peppers, followed a lot of tutorials for medicinal plants, as they are so common, set up a grow tent. I did note that peppers will require more heat than normal.

100W LED lights (Viparspectra), 70cm*70cm*160cm mars hydro tent + extractor and filter (turns out I don’t need the filter, but it’s in there now).

Starting with the pepper seeds, I tried to start with soil,Problem no. 1, bought the wrong stuff, mostly wood chip. Mixed it 50% with perlite. Got them to germinate in 7 days on top of the gaming PC which averages around 28*C exhaust temp. When they sprang out of the ground and all 7 produced their seedling leaves I moved them under the LEDs in the grow tent… in the garage. No humidity dome either.

Friends told me to put the LEDs right down on them and on for 16 hours a day. So I put them on full and at about 5″ from the seedlings. I also installed a webcam to time lapse them over time, a temperature and humidity sensor.

Problem no 2. Temperature. I had seen this coming and had a 250W heater in the tent. However with the extractor off it would oscilate wildly from 15*C to 25*C, only lowered slightly with a circ fan. With the extractor on, the heater ran 24/7 and by tuning the extractor I got it down to running stable between 20*C and 25* depending on the outside temp. Too expense to run.Solution: Automate the heater with a Wifi power bar. Bang, stable 20/21*C. Heater cycles about once every 5-10minutes giving 20.5 +/- 0.6*C

However by this stage the plants had stopped growing and pointed their leaves up like praying hands hiding from the light. Over watered? I left them until the tray was light, nothing, watered the hell out of them, no response.

Problem no 3. Using air heating in a confined space with limited ventilation to maintain heat… leads to dry air. Humidity slowly fell over a day or so to 25% until experiments with soaked kitchen roll and jars of water in front of the heater failed.Solution: Humidifier with an auto function at 60%RH.

A few evenings making and tinkering and I had environmental control over soil temp, ambient floor temp, humidity and monitoring of the upper temp, the garage temperature and outdoor temp/humidity. All graphed in grafana and being controlled by a python script. W00t!

Problem no 4. Self inflicted due to blonde moment and beer. I got cocky. After a few beers one evening I decided to make it more tropical for my continually stationary pepper seedlings. I manually set the humidifier to 75% and the temperature target to 25*C. It only took it half an hour to stabilize at the new figures. All was good. So not wanting to leave it over night at those settings I dropped the temps back and went to bed.

Tropical, yes. Absolutely. Night time, yes. What happens in the jungle at night time when temps drop? What mixes with electronics about as well hippies at a corporate function? Dew. 100% Humidity. Instant condensation on any surface cooler than the due point…. what at that stage was everything. It literally rained.

As cascade failures go, it was fairly amusing as a profession software engineer to pick apart in the post mortom the next day. The first failure seems to have been the humidity sensor in the humdifier which, because someone wrote it’s firmware on a Friday, went to 100% misting output and stuck there. My humidity sensor then pinned at 100%, the temperature sensor dropped offline around 5am. I became aware of it around 8am when I pulled the plug on the humdifier, turned the extractor up full and the heater on full. Then observed the graphs and time lapse photos… the webcam survived it’s sauna, as did the microcontroller mounted in the gland and the DS18B20 sensors in their metal caps.

Thankfully everything dried out… or rather is still drying out. The humidifier even recovered, but it’s off until the tent dries out properly and will be reinstated with a safety shut off should humidity get over 85% in future.

The pepper plants which survived (?) this, still appear to be alive and have grow nodes for their first true leaves, but it looks like the seedling leaves are determined to remain closed, even now I have moved them out of the tent and indoors under a normal kitchen light.

Reading up the LEDs the manual that came with it does say to place it at 20-24″ and introduce seedlings to it at 40% for a few days, then 60% until they have real leaves. Ooops.

Peppers now, they aren’t dead, but they are a 3-4 weeks old.


Lettuce in the propagator instead.



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