Improving upon the sun—LED lights fuel plant growth in space

January 10, 2018 by Michael Dixon, The Conversation
Light-emitting diodes (LEDs) used in medical devices and for growing plants, like potatoes seen here, are used by NASA to grow plants in space. The U.S. space agency plans to grow food on future spacecraft and on other planets as a food supplement for astronauts. Credit: NASA

If you've ever seen the film The Martian, you're familiar with "plants in space." The protagonist in the film, played by Matt Damon, successfully harvests potatoes on Mars to feed himself when he's stranded on the planet.

Far-fetched? Not at all.

Here at the University of Guelph in our Controlled Environment Systems Research Facility (CESRF), we've been investigating controlled-environment and how best to get the most out of in terms of food, oxygen, fresh water and carbon dioxide scrubbing —in other words, human —for decades. Since the mid-1990s, we've been home to the Space and Advanced Life Support Agriculture (SALSA) program.

These research activities form Canada's contribution to the niche field of space exploration known as "biological life support" —or plants in space.

Research and technology developments in this field include:

  1. Biofiltration of indoor air (with terrestrial applications to mitigate "sick building syndrome");
  2. Disinfection methods that leave no toxic residue;
  3. Ideal candidate crop selection as a source of food on long-term space exploration missions;
  4. Reduced pressure studies to develop low-mass, inflatable "greenhouses" for the moon and Mars;
  5. Environment control "recipes" for , CO2, temperature, humidity, nutrients and water and, of course, a host of sensors of these environmental variables to facilitate plant growth.

Among the more recent tools in the pursuit of high-density production of a range of crops are light-emitting diodes (LEDs) as a source of photosynthetic energy. In our research facility, we're working to refine and perfect LED technology.

The advent of ever-increasing intensity and efficiency of LEDs has expanded their use beyond cars and street lights. We now routinely consider LEDs as supplemental, or even sole-source, lighting for plants.

LEDs have a unique narrow wave band of light that represents a small sub-section of the solar spectrum. There are many examples of LEDs that virtually fill the spectrum of visible light and beyond to include ultraviolet bands and far-red to infra-red components.

We know quite a bit about how plants respond to various wavelengths, and certain combinations of wavelengths of light, based on research with filters and other more conventional lights that include high-pressure sodium, metal halide and fluorescent lighting.

Improving upon the sun

However, LEDs offer the opportunity to design a spectrum and assess the responses of plants to some very unusual colour combinations.

Improving upon the sun—LED lights fuel plant growth in space
Results of lettuce plants grown under the three different light spectra showing differences in accumulated biomass and expressions of anthocyanin (pigment) in the leaves. These plants also tasted different, indicating additional secondary metabolite responses to the colour of the light. Credit: University of Guelph, CESRF

Among the suite of environmental variables that optimize plant production, the most powerful in determining just how a plant responds to its context is lighting.

Indeed, with the new attributes of LED lights, we can seemingly improve upon the sun in the production of various plant commodities.

The latest research findings on various spectral qualities—colours, in other words—provide details on specific responses in some plants related to the plant's size, shape and photosynthetic efficiency. We can even modify the content of metabolic compounds that influence the colour, taste and medicinal properties of a plant.

Those medicinal properties have attracted the scientific and industry communities in the evolving phyto-pharmaceutical —medicines from plants —sector.

Low-cost production of reproducible, high-quality medicinal compounds is the main focus of the sector, and the range of commodities is growing rapidly. They include cancer drugs, vaccines for a range of viral pathogens, antibodies and, of course, cannabis or marijuana. Cannabis has a new-found status due to changes in laws in Canada and elsewhere governing the use of this unique plant.

But these technologies, especially LED lights born in Canada's research community, bring with them the responsibility to get it right —and the danger of getting it wrong is very real.

Early attempts in the recreational cannabis community a number of years ago when LEDs were deployed as a photosynthetic light source in efforts to reduce energy usage in basements and closets didn't work so well.

It became obvious to those early pioneers growing cannabis under LEDs that something was amiss. The vague idea that some red and blue lights would do the job was quickly dispelled, but the stigma of those early failures still haunts the proponents of LEDs in that sector today.

'Refining recipes'

We've come a long way since those missteps and misconceptions about how to use LEDs, but we have more work to do.

Researchers at the University of Guelph's CESRF have been working with industry collaborators in the phyto-pharmaceutical sector (Plant Form Corporation), the medical cannabis sector (ABcann Medicinals Inc.), the LED sector (Intravision Light Systems) and the controlled environment sector (Conviron Ltd.) to refine recipes of environment control to grow plants for medicinal purposes.

We're also working to develop the best management practices to serve these industry sectors and the Canadian public—as we seek to make the most of the latest technologies in controlled environment plant production.

And given U.S. President Donald Trump's recent comments about sending American astronauts back to the moon and Mars, there's every likelihood that we'll get to test our "plants in space" expertise some time soon.

Explore further: Growing cannabis with modern science and technology

Related Stories

Growing cannabis with modern science and technology

November 20, 2017

In Canada and around the world, legal cannabis producers face many challenges: varying government regulations, high security requirements and a lack of reliable information on how to grow their crops.

Ornamental plant seedlings grown with LED lights at Purdue

October 29, 2014

Purdue University researchers' success in using red and blue LEDs as the only source of light to grow ornamental plant seedlings indoors has led to a new phase of determining whether they can reduce production time with more ...

Researchers test effects of LEDs on leaf lettuce

November 19, 2013

In the life cycle of plants, most developmental processes are dependent on light. Significant biological processes such as germination, shade avoidance, circadian rhythms, and flower induction are all affected by light. Recent ...

Recommended for you

Superflares from young red dwarf stars imperil planets

October 18, 2018

The word "HAZMAT" describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by ...

Blazar's brightness cycle confirmed by NASA's Fermi mission

October 18, 2018

A two-year cycle in the gamma-ray brightness of a blazar, a galaxy powered by a supermassive black hole, has been confirmed by 10 years of observations from NASA's Fermi Gamma-ray Space Telescope. The findings were announced ...

Astronomers catch red dwarf star in a superflare outburst

October 18, 2018

New observations by two Arizona State University astronomers using the Hubble Space Telescope have caught a red dwarf star in a violent outburst, or superflare. The blast of radiation was more powerful than any such outburst ...

Magnetic fields may be the key to black hole activity

October 17, 2018

Collimated jets provide astronomers with some of the most powerful evidence that a supermassive black hole lurks in the heart of most galaxies. Some of these black holes appear to be active, gobbling up material from their ...

Astronomers find a cosmic Titan in the early universe

October 17, 2018

An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (2) Jan 10, 2018
Since the soil on Mars has been found to be highly toxic Damon's Farm cannot be. He would have been poisoned within a few days (MIT has estimated all 'colonists' would be dead from cosmic radiation within 68 days of arrival). Among the many, many other problems with that movie (winds on Mars don't get anywhere near high enough to knock over a space ship) is the idea that he could plant potatoes in toxic soil, fertilize them with human waste (!), which is the most common cause of e coli incidents.
Stop drinking the Musk Kool-Aid; colonization of Mars is not going to happen, so how about fixing things here on Earth?
5 / 5 (3) Jan 10, 2018
Since the soil on Mars has been found to be highly toxic

Where do you get this from?

The only region where perchlorates make bacterial life difficult is near the surface. This doesn't mean that all the soil cannot be used for growing any kind of biologicals.
Mark Thomas
5 / 5 (1) Jan 10, 2018
Stop drinking the Musk Kool-Aid; colonization of Mars is not going to happen, so how about fixing things here on Earth?

So says the anonymous expert of nothing. Paraphrasing Wolfgang Pauli, your comment is so pathetic, it isn't even good enough to be wrong. Plants have already been grown in simulated Mars soil. Mars is the only planet we have a chance of colonizing in the solar system beyond Earth for the foreseeable future, so giving up on Mars is just plain giving up, not a good idea. It is fundamentally flawed reasoning is to wait on exploration and colonization of Mars until life is perfected. Why set such a ridiculous standard? How about waiting on tax breaks for the rich until we succeed in "fixing things here on Earth?"

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.