Adventures in Hydroponics (Weeks 23-26)

Automation edition

Well, another semester has gone by (time flies!). Let’s see what happened to the garden!

Day 163 (Nov 28, 2014)
Things got busy and winter came! Wind and temperature weren’t being super kind to my plants, so they took refuge in our living room. Which might turn into a permanent home — we’ll see. Anyway, the semester rolls along and the plants continue to get bigger.

But the question is: where is the promised automation? Wasn’t that the point all along? So, here’s the start of the water automation. First step: water drainage from the trays. Look, a first water test!

Day 178 (Dec 13, 2014)
First things first: prepping the system.

Fixing the drainage tubes to the trays resembles good soldering practice: a solid mechanical connection, along with good electrical connection (with solder). Here, that means, respectively: physically putting the 0.25″ tube through a hole in the tray and splitting the top end, and then attaching the tube from both top and bottom to the tray (with glue).

My system consists of one feeder tube per plant. With so many feeder tubes, it’s important to maintain sufficient pressure inside each tube. These fittings restrict the outflow, which did the trick. The long pieces are stakes, which position the feeder tubes.

Day 179 (Dec 14, 2014)
The water automation system itself is an open loop closed system. That is, water pumps out of this 20 gallon reservoir into a main 0.5″ tube, which runs out to 0.25″ feeder tubes to each plant. The extra water sinks to the bottom of the tray, which drains back into the reservoir. Remember: safety first!

Day 181 (Dec 16, 2014)
With 7 hours before I take off for Seattle, there are two outstanding issues: the system needs a timer and sometimes the trays don’t drain. Eep!

Good thing duct tape fixes many things. When the drainage tubes are submerged in the reservoir and there is air sitting in the tube, there is simultaneous atmospheric pressure from both the reservoir and the plant tray. The pressure from the plant tray is insufficient for forcing the water out of the drainage tube, so the water does not drain (thanks Joey, for the explanation!). Solution? Don’t submerge the drainage tubes in water in the first place.

The timer was easy enough too to set up. 1 minute watering, twice per day is what we decided.

And last but not least, I filled up the reservoir, dumped in some nutrients, and it’s ready to go!

Until next year, plants! I’m leaving you in good hands with Philipp, in case the system decides to take over the house! (Thanks Philipp!)

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