An update on my second attempt at hydroponic growing! I posted just over a week ago to introduce the new plan, growing some hydroponic basil, and am pleased to report that at the moment things are moving along well.

Hopefully you can see that the seeds have begun to move quite nicely – some are around 1 inch tall by this point, which I think is good going for 10-day-old basil (is it?). So far, the seeds have been kept in a propagator in dark conditions (it’s had a blanket piled on top of it to serve the dual purpose of keeping out light and inching the temperature up a tiny bit). I’ve had to re-moisten the whole grid twice with a spray bottle of light nutrient solution since the first immersion of the cubes.

Something I’ve been doing this time which I didn’t manage to do with the last attempt is keeping a much more accurate eye on the environment; the temperature specifically. I’ve set up a Raspberry Pi using one of the waterproof flexibly corded DS18B20 temperature sensor chips to take regular logs of the temperature inside the propagator. It’s been hovering a tiny bit too low for a few days due to the ambient conditions in my flat, as you can see from the below graph of the temperature dump (YES I made a graph YES you love a bit of it don’t you):

Recent passive efforts have brought it up a bit closer to the desired 21C, including my girlfriend’s illness and the ensuing incredibly high heating! However, today I’ve picked up this propagator warming mat which I’m going to hook up to be actuated by the Raspberry Pi doing the temperature monitoring – I hope to get this going as a thermostatic controller. The mat’s quite versatile, so I’m considering taking it with the plants when I migrate them to the DWC proper, sitting the small reservoir on top of it and taking the same approach, but that’ll depend on the success over the next few days.

Anyone notice something more I could be doing? When should I look to start exposing the seedlings to light? The moment even the first small leaves unfurl?

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