I’m Building a Pi-Controlled, Crypto-Heated Hydroponic Garden

Raspberry Pi + Crypto + Hydroponics + Solar = Some Wildly High Tech Tomatoes

Thomas Smith
Jan 24, 2020 · 6 min read
Photo by Harrison Broadbent on Unsplash

I am planning to build a Raspberry Pi controlled, cryptocurrency heated, indoor hydroponic garden that uses recycled water and solar power to grow plants in my garage.

No, this isn’t a clickbait article where I try to throw as many irresistible tech concepts into a headline as possible. This is really a project, and I’m really doing it.

Why? There are a bunch of reasons.

For one thing, I’ve been studying new models for crypto mining in a ton of detail. And I’ve been obsessing about solar for a while, too. In this very publication, I wrote an article talking about combining the two.

I’ve also been experimenting with crypto heating for over a year. It’s nice to add a little extra heat to my house with a crypto computer, but I think one of the most promising applications of crypto waste heat is for industrial and commercial uses, like growing plants in cold climates. Greenhouses already use a ton of electricity for heat — why not derive this from cryptocurrency mining, as this 5 acre tomato greenhouse has done?

Hydroponics and indoor farming is a fast-growing (pun certainly intended) field, too. Much of this growth has been driven by innovation in the cannabis industry. I have no interest in growing cannabis. But I’m curious to see how innovations like improved grow lights, fertilizers, etc. can be applied to growing vegetables or other plants indoors.

Hydroponics also appeals to the scientist in me. Dirt seems like an almost magical substance, which requires the investment of time, careful attention, and the addition of witches-brews like compost tea, bacteria, and fermented fish parts. Hydroponics seems like a cleaner, more precise way to feed plants.

Also, I’m a very incompetent gardener. I never have any idea when to water plants, or even how to tell when they’re dying from too much water or not enough. With hydroponics, I’m assuming you don’t need to worry about watering. Then again, I know nothing about hydroponics.

The Raspberry PI aspect feels obvious to me. I’ve been working with the PI and other microcontrollers for the better part of a decade. I’ve served as a Beta tester for Arduino, and even built products around the boards. If I want to build an automated indoor garden, it’s going to need to have a Pi at its core.

Also, and perhaps most importantly, my kid loves plants, but even here in California, it’s too cold for him to grow his tomatoes outdoors. That’s reason enough to build a wildly complex, sustainable, indoor garden right there.

So how would this proposed garden actually look?

What I’m imagining is a desktop-sized greenhouse that I can put in my unheated garage. For starters, it would by fed by waste heat from my cryptocurrency mining computer. The computer puts out about 220 watts of waste heat when mining, so that’s more than enough to heat a small greenhouse.

I’m imagining a hydroponic garden, primarily because I’m curious about this. And soil is yucky.

If possible, I would get the water from captured rain during the CA rainy season (winter), and the condensate drain of my suburban-sized AC unit in the Summer, where water is otherwise wasted (it makes about a gallon per hour.) I would use grow lights to keep the plants growing 24 hours per day.

Ideally, I’d like this to be totally hands off and automated. We travel quite a bit, so this is something that should be able to run for a few weeks at a time with no input. Also, I’m lazy, and can’t be bothered to monitor plants — I’d much prefer to let some fancy AI do it for me.

To achieve that, I’m planning to use a Raspberry PI to sense and control the internal temperature of the greenhouse (probably by controlling how much of that hot, hot crypto air enters it), control the hydroponics system (whatever that entails), monitor and control lighting, and likely stream the whole thing online via a camera, so I can monitor it remotely. I could even build in a plant-health-sensing camera using IR, which is apparently a thing and can be done with a PI.

Ideally, I’d like at least the Pi, and possibly the grow lights, to run off solar from my private microgrid. I’d like to run the crypto PC off solar too, but my HOA frowns on putting off-grid panels all over one’s roof. Such is life.

The Pi draws almost no power at all. I have no idea how much power grow lights draw, but hopefully solar could at least be an offset to that.

Oh, and there should be plants in it. We can’t forget about those.

I wasn’t sure what would be best to grow with this admittedly overly complex setup.

At first, I thought about growing plants that would filter the air, cutting down on indoor air pollution in my home. I read lots of articles about this that begin with the dubious words “According to studies by NASA…”.

Then I read in-depth expose in The Atlantic that basically confirmed all those articles are bunk. Plants don’t filter the air, unless you literally line every surface of you home in them. That tracks--plants don’t have a ton of surface area (unlike, say, activated charcoal), so they’re not going to do much for air quality. So that use case was out.

I also thought about growing something to sequester carbon, to prove this could be done at home. But the plants that sequester carbon the best are all giant evergreen trees. Those won’t fit in my garage. And anything else has a disquietingly small impact. Looks like I’ll have to invent something else to solve climate change.

What I’ve arrived at is growing some kind of food plant. This could be dwarf tomatoes (again, my son is an expert), or perhaps a high-value cash crop like a bunch of kitchen herbs (parsley, sage, rosemary, and thyme, with apologies to Paul Simon) that could replace those little $5 plastic trays from Whole Foods that my family would definitely otherwise buy.

Something that grow continuously would be nice, so I could harvest little bits throughout the year. I’m not totally sure of the best plant yet, but it will almost certainly be something you can eat or use as an ingredient.

Now that I have the basic ideas in place, the next step is to actually build this.

My first move will be to see if anything even remotely similar already exists. Ideally, I could find something which covers the basics, like the greenhouse itself and perhaps the plumbing for the hydroponics (they use plumbing, right?).

I could then modify this to add my own smart features. No need to totally re-invent the wheel.

There are several popular kits out there. Add in a small greenhouse, some extra grow lights, the crypto/solar/pi systems, and I’d be in business. I’m under no false illusions that this would be a money saving endeavor. But I think it would be a great way to experiment with some of today’s most exciting technologies — blockchain, microcontrollers, hydroponics, solar, and more.

And some of yesterday’s most exciting technologies, too — like heirlooms plants and kitchen herbs you can’t get at the grocery store.

Oh, and tomatoes. First and foremost, tomatoes.

Follow along here as my crypto/hydroponic/solar/pi greenhouse comes together, and I’ll share the experience along the way.

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Thomas Smith

Written by

Co-Founder & CEO of Gado Images. I write, speak and consult about tech, privacy, AI and photography. tom@gadoimages.com

The Startup

Get smarter at building your thing. Follow to join The Startup’s +8 million monthly readers & +787K followers.

Thomas Smith

Written by

Co-Founder & CEO of Gado Images. I write, speak and consult about tech, privacy, AI and photography. tom@gadoimages.com

The Startup

Get smarter at building your thing. Follow to join The Startup’s +8 million monthly readers & +787K followers.

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