Plants compared side-by-side, with LED-illuminated plants growing way more than the sunlight-illuminated plants

Plant Growth Accelerated Tremendously With LEDs

April 30, 2022 by Arya Voronova 37 Comments

[GreatScott!] was bummed to see his greenhouse be empty and lifeless in winter. So, he set out to take the greenhouse home with him. Well, at least, a small part of it. First, he decided to produce artificial sunlight, setting up a simple initial experiment for playing with different wavelength LEDs. How much can LEDs affect plant growth, really? This is the research direction that Würth Elektronik, supporting his project, has recently been expanding into. They’ve been working on extensive application notes, explaining the biological aspects of it for us — a treasure trove of resources available at no cost, that hackers can and should learn from.

Initially, [GreatScott!] obtained LEDs in four different colors – red, ‘hyper red’, deep blue, and daylight spectrum. The first three are valued because their specific wavelengths are absorbed well by plants. The use of daylight LEDs though has been controversial. Nevertheless, he points out that the plant might require different wavelengths for things other than photosynthesis, and the daylight LEDs sure do help assess the plants visually as the experiment goes on.

Next, [GreatScott!] borrowed parts of Würth’s LED driver designs, creating an Arduino PWM driver with simple potentiometers. He used this to develop his own board to host the LEDs.

An aluminum PCB increases heat dissipation, prolonging the LEDs lifespan. [GreatScott!] reflowed the LEDs onto it with solder paste, only to find that the ‘hyper red’ LEDs died during the process. Thankfully, by the time this problem reared its head, he managed to obtain the official horticulture devkit, with an LED panel ready to go.

[GreatScott!’s] test subjects were Arugula plants, whose leaves you often find on prosciutto pizza. Having built a setup with two different sets of flower pots, one LED-adorned and one LED-less, he put both of them on his windowsill. The plants were equally exposed to sunlight and equally watered. The LED duty cycle was set to ballpark values.

The results were staggering, as you can see in the picture above — no variable changing except the LEDs being used. This experiment, even including a taste test with a pizza as a test substrate, was a huge success, and [GreatScott!] recommends that we hit Würth up for free samples as we embark on our own plant growth improvement journeys.

Horticulture (aka plant growing) is one of the areas where hackers, armed with troves of freely available knowledge, can make big strides — and we’re not even talking about the kind of plants our commenters are sure to mention. The field of plant growth is literally fruitful and ripe for the picking. You can accomplish a whole lot of change with surprisingly little effort. The value of the plants on your windowsill doesn’t have to be purely decorative, and a small desk-top setup you hack together, can easily scale up! Some hackers understand that, and we’ve started seeing automated growing solutions way before Raspberry Pi was even a thing. The best part is, that you only need a few LEDs to start.

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Hardware Store Hydroponics

October 5, 2020 by Brian McEvoy 34 Comments

Science fiction movies often portray horticulture in the future, be it terrestrial or aboard spacecraft, with hydroponic gardens overflowing with leafy greens and brightly colored fruit. There is no soil, just clear water that hints at future-people creating a utopia of plant strains untethered from their earthly roots.

This star-faring food production method is not fiction if you forego the polycarbonate tubing, neon accent lights, and gardening robots. For his 2020 Hackaday Prize entry, [AVR] shares how he creates a bed for sixteen plants with parts sourced at a nearby home-improvement store. It may lack the visual pizzaz of the Hollywood versions, but it will grow soil-less crops on a hacker budget.

The starting point for this build is a sturdy wooden base. The PVC tubing and fence parts on top are light, but the water inside them will get heavy, and if you grow large plants, they become surprisingly heavy. Speaking of water, the sub-category of hydroponics this falls under is Nutrient Film Technique, or NFT, which uses a shallow stream of water laden with all the nutrients for plant growth. The square fence posts provide a flat top for mounting mesh cups where the plants grow and a flat bottom where the stream continuously flows. A basin and pump keep the plants refreshed and fed until they are ready for harvest.

Compile A Hydroponics System From Source

June 16, 2020 by Bryan Cockfield 18 Comments

Tending to a garden is usually a rewarding endeavor, as long as there is good soil to work with. If there isn’t, it can either get frustrating quickly having to deal with soils like sand or hard clay, or it can get expensive by having to truck in compost each year. Alternatively, it’s possible to set up systems of growing plants that don’t need any soil at all, although this requires an automated system otherwise known as hydroponics to manage water and nutrients sent to the plants.

This setup by [Kyle] is unique in that it uses his own open-source software which he calls Mycodo to control the hydroponic system. It is loaded onto a Raspberry Pi 4 (which he notes can now be booted from a USB drive instead of an SD card) which controls all of the peripherals needed for making sure that the water has the correct amount of nutrients and chemical composition.

The build is much more than just a software control panel, though. [Kyle] walks through every part of setting up a small hydroponic system capable of effectively growing 15-20 plants indoors. He grows varieties of lettuce and basil, but this system can work for many more types of plants as well. With just slight variations, a similar system can not only grow plants like these, but fish as well.

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Adding Mobile Control To Your Gardening

October 11, 2010 by Mike Szczys 13 Comments

[The Cheap Vegetable Gardener] wanted to check in on his garden from the road so he wrote a control app for his WinPhone. The hardware work is already done; having been built and tested for quite some time.

The implementation comes in two parts, both shown in the chart above. The grow box is behind a firewall as you don’t want random folks turning on the water and grow lights on a whim. The first part of the interface takes care of this separation by providing a set of functions on the host machine. The second portion is the phone app itself which calls those functions and displays all the pertinent information from the status of the lights, heater, exhaust, and water pump, to the current temperature and humidity. He’s even used Google Charts to graph data over time. The app itself took about two hours to code with no prior experience, a testament to the level of approachability these tools are gaining.

Greenhouse Guard

July 24, 2009 by Zach Banks 15 Comments

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[Seth King] sent in his latest hack where he used an Arduino to regulate various aspects of a greenhouse. He has sensors for soil and air temperature as well as light and moisture. He built a custom circuit that uses relays to power fans, lights, and heaters. Using timers and the sensor data, the devices can be triggered to create the perfect environment for sprouts. He hopes to make the whole thing wireless by integrating XBees, but for now he ran a USB cord to his computer.

Related: Automatic grow light

Automated Plant Growing

January 6, 2009 by Caleb Kraft 29 Comments

[youtube=http://www.youtube.com/watch?v=7tnfcTAoggI]

The Cheap Vegetable Gardener sent us his fully automated grow chamber project. In the quest to have fresh strawberries year round, they’ve made some progress in the area of automating their plant care. The whole thing is controlled by a computer that can turn on/off the lights and adjust the temperature. It also takes snapshots and logs the environment conditions so you can chart it all out nicely. The automated watering feature isn’t done yet, but hopefully will be soon.