The challenge of space gardening: One giant 'leaf' for mankind

Tomatoes grow in an LED-lighted box, similar to what astronauts use to grow lettuce on the International Space Station, at Fairc
Tomatoes grow in an LED-lighted box, similar to what astronauts use to grow lettuce on the International Space Station, at Fairchild Tropical Botanic Garden in Miami on April 25, 2018

It's not easy having a green thumb in space.

Without gravity, seeds can float away. Water doesn't pour, but globs up and may drown the roots. And artificial lights and fans must be rigged just right to replicate the sun and wind.

But NASA has decided that gardening in space will be crucial for the next generation of explorers, who need to feed themselves on missions to the Moon or Mars that may last months or years.

Necessary nutrients, like vitamins C and K, break down over time in freeze-dried foods. Without them, astronauts are increasingly vulnerable to infections, poor blood clotting, cancer and heart disease.

So the US space agency has turned to professional botanists and novice gardeners—high school students, in fact—to help them practice.

"There are tens of thousands of edible plants on Earth that would presumably be useful, and it becomes a big problem to choose which of those plants are the best for producing food for astronauts," explained Carl Lewis, director of the Fairchild Tropical Botanic Garden, which is leading the effort.

"And that is where we come in."

Useful foibles

The Miami-based garden has identified 106 plant varieties that might do well in space, including hardy cabbages and leafy lettuces.

They have enlisted 15,000 student botanists from 150 schools to grow plants in space-like conditions in their own classrooms.

The four-year project is about midway through, and is paid for by a $1.24 million grant from NASA.

Using trays rigged with lights that mimic the grow boxes used in space, students must tend to the plants and record data on their progress, which eventually gets shared with NASA.

"We're not using typical gardening equipment," said Rhys Campo, a 17-year-old high school student who tried her hand at growing red romaine lettuce this year.

"We have setups that are a lot more high-tech."

High school students specializing in botany attend an event at Fairchild Tropical Botanic Garden in Miami where they talk about
High school students specializing in botany attend an event at Fairchild Tropical Botanic Garden in Miami where they talk about space gardening with astronauts Ricky Arnold and Drew Feustel via video downlink from the International Space Station

Still, some plants get overwatered, some classrooms are hotter or colder than others, and holiday breaks may leave the grow boxes unattended.

In Campo's class, the lettuce dried up, and students were unable to taste it.

Such foibles have turned out to be an unexpected but useful part of the project, said NASA plant scientist Gioia Massa.

"If you have a plant that does well in all that variability, chances are that plant will do well in space," she told AFP.

New textures

Astronauts living at the space station, 250 miles (400 kilometers) above Earth have encountered their share of failures while gardening in orbit, too.

The first portable growing box for space, equipped with LED lights, called Veggie, was tested at the orbiting outpost in 2014.

Some of the lettuce didn't germinate, and some died of drought.

But astronauts kept trying, and finally took their first bite of NASA-approved space-grown lettuce in 2015.

Now, there are two Veggie grow boxes at the ISS, along with a third, called the Advanced Plant Habitat.

The food being grown is only occasionally harvested, and amounts to just a leaf or two per astronaut, but it's worth it, said NASA astronaut Ricky Arnold, during a live video downlink with students at Fairchild last month.

"The textures of food are all kind of very similar," he said of the freeze-dried fare available on board the ISS.

"When we are able to harvest our own lettuce here, just having a different texture to enjoy is a really nice diversion from the standard menu."

JoLynne Woodmansee (L), a teacher at BioTECH High School, sits with her students during at an event at Fairchild Tropical Botani
JoLynne Woodmansee (L), a teacher at BioTECH High School, sits with her students during at an event at Fairchild Tropical Botanic Garden in Miami on April 25, 2018, where students spoke live with astronauts on the International Space Station
The ideal space veggie

Plants don't need gravity in order to grow. They just orient themselves to the light.

According to Massa, a good space plant has to be compact and produce a lot of edible food.

Plants also have to do well in a spaceship like the ISS, which has a temperature of 71 degrees Fahrenheit (22 Celsius), 40 percent relative humidity, and high carbon dioxide—some 3,000 parts per million.

"That is something plants aren't adjusted to," said Massa. "On Earth it is about 400 ppm."

Under a system Massa described as akin to hydroponics but not exactly the same, space plants also have to germinate from a plant pillow with only a small amount of dirt, do well under LED lights, and be microbially fairly clean, because it is hard to wash vegetables in space.

Some of the student-tested crops are expected to launch in coming months, including dragoon lettuce and extra dwarf pak choi.

By next year, tomatoes could be on the menu.

Connection to Earth

NASA is looking into the possibility of robotic space gardening, to automate the process so crew can focus on other tasks.

But many astronauts say they like tending to plants, because it helps them maintain a connection to Earth.

"The psychological benefits can be important for astronauts," said NASA research scientist Trent Smith.

Besides—as many gardeners know—having a plot dry up or be devoured by mold isn't the end of world.

"The thing that the students learn is that making mistakes is okay," said JoLynne Woodmansee, a teacher at BIOTech High School in Miami.

"The whole process of science is all about building. You can't learn something new without making a mistake."

Explore further

Salads in space? Astronauts try growing own veggies

© 2018 AFP

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May 11, 2018
They should try growing algae or microbes. They are more energy efficient. Microbes can grow on hydrogen. Problems would appear (large bioreactors may be needed, special food processing may be required as we don't usually feed on algae and they may even be toxic - i.e. products from dead cells may require washing etc.) but instead of a leaf/person, they may get a full meal.

May 11, 2018
Algae, fungi, yeasts and the like will all eventually be part of the waste recycling system, but except for a few of the mushrooms they're not **FUN** to eat. They don't have interesting textures or flavors that people enjoy eating. They also tend not to have a lot of the vitamins and minerals that we need, like C and K (mentioned in the article).

In an off-planet colony, whether on the Lunar surface or in deep space, growing its own food there will be a lot of stems, leaves, seeds, roots, etc. left over. Small animals like guinea pigs and quail can quickly process them into usable biowaste while providing (very tasty) meat. Tilapia and freshwater anchovies are already used on Earth to process sewage into human-acceptable food. It won't be a "human colony" it will be an "Earth-life colony" that gets us off this planet and into space.

May 11, 2018
@Cusco: while most people would love that, it is not a very efficient process and it will require lots of space, i.e. a big ship. Right now it may be more important to feed the crew in an efficient way. People can skip flavour and texture most of the times if they are hungry. The food in food is more important than those.

May 11, 2018
G, the problems growing algae for food within enclosed environments are legion.

Have you ever smelled algae mats in nature? Trapped in a spacecraft, you can't open a window to let out the stench.

What algae or other cultured microorganisms can provide necessary nutrients? How stable are the cultures with the stresses of space travel?

It made me laugh ...high carbon dioxide—some 3,000 parts per million. "That is something plants aren't adjusted to," said Massa. "On Earth it is about 400 ppm."

That humans can tolerate high CO2 better than plantlife. Funny!

And there is the psychological factor. Would you eat the product, endlessly repetitious?
After harvest processing to render the gloop edible would ruin the stability of the nutrients.

If you have ever experienced aircraft meals and compared them to the same meal at ground level? Your own senses react differently. Smell and taste and physiological needs seriously constrain what is possible and reliable.

May 11, 2018
So long are we are limited by chemical rocket technology it will be very expensive to get things like food water radiation-shielding etc into space.
The low gravity of the moon and it's lava tubes make for an ideal stepping stone to our solar system. The moons low gravity makes practical momentum exchange tethers in polar orbit to get on and off the moon.
The lava tubes are huge pre-built and have withstood the test of time. Kilo-power reactors can provide power at night along with lunar orbital mirrors.
Lunar dust is easily separated and provides ideal feed-stock for metal 'printers'. The high school kids would be much more motivated if it looked like they could actually get jobs off planet. We haven't done much in space for 40 years but once that changes there will be a whole new future for mankind.

May 11, 2018
Permanently excluded from planetary landings in zero gravity!

We cannot live in space without gravity 10m/s*, what are we going to do when we send an away team to the planet's surface when we live in zero gravity.
We are permanently house bound in zero gravity in our space transporter.

Please can you think outside the box?
If we go into space without going into orbit, 4000miles from earth gravity is still 1/4 earth's gravity and it increases again when we fly closer to the planets.
The key to maintaining gravity is not to go into orbit

May 11, 2018
@rwillisj: Methylococcus is grown on methane for animal food: https://en.wikipe...psulatus
I suppose it would work for human consumption as well with some processing. Spirulina is also used as food supplement; some toxic effects have been found though, maybe because dead cells were not washed away, or maybe because it is simply toxic.

Aircraft meals are not that bad actually. I've eaten things from nature that would be considered worse (leaves, pine inner bark - although that is pretty good when roasted over fire). I actually like foods with less taste. I'm probably fit for space life. :)

That 3000 ppm CO2 probably dumbs down the astronauts:
They must be pretty well prepared not to have made some big mistakes until now.

May 11, 2018
It is horticulturalists you want. Botanists are concerned only with plant anatomy and categorization .
Cannabis would do well under those conditions

May 12, 2018
DDc, If we can solve the dust problem, our Moon might be usable for automated facilities.. We do not know what is in the lava tubes nor do we know how usable those could be. 'Miner's Lung' disorders would be chronic. As it is here on Earth.

granville points out the reality of colonization. What are the long-range effects of Lunar micro-gravity on Humans, over several generations?

G, animal feed is not the same as Human consumable. That's why they got all those extra stomachs for processing the feed.In addition to the difference in nutritional needs for different species.

The article points out that the Space Station crew are constrained by a very limited water supply. From thoroughly washing toxins & toxic residues from their grown foods.

Have you ever been trapped in an institution where your daily diet was always the same damn thing? Every damn day?

May 12, 2018
mack, I think you missed the point of this article. It's not just peoples needs but also peoples wants. Supplements have limited shelf-life. In addition to failing to account for each person's biological differences.

And the psychological effect of gardening. Plus the desire for novelty with cherished comfort fresh foods. Yes, I know, an oxymoron. Welcome to the perversity of being human.

Having a combination, a balance of artificial and natural methods of recycling the air inside an enclosed habitat would be more efficient. More pleasing for the inhabitants. As well as increasing safety margins.

Bong, The environment outside is cold-bloodily unforgiving. Dopers and drunks and stupid will have a very short lifespan in any Space environment. As well as endangering everyone trapped with them and wrecking megabucks of unreplaceable equipment.

Oxygen saturated enclosures are death traps.

May 12, 2018
Algae and microbes are almost certainly going to require a liquid medium, which is a nightmare all its own in microgravity. The added problems of gas exchange, harvest or extraction, and the possibility of infection by something harmful or noxious make it a nonstarter.

May 13, 2018
rs, right on! Also allergic reactions that will differ in intensity from person to person and even day to day for each person.

Cannot imagine the waking nightmare of being trapped in a pressure suit for EVA and having a sneezing jag! Or running nose and spasmodic coughing from a respiratory illness or allergy.

Your spacecraft/habitat is malfuncted? You can't just dope yourself up, go back to bed and pull the covers over your head. Hoping someone else will turn out and take care of fixing your specialty.

May 14, 2018
The microbestuff is not so bad. We have microbes inside us. We usually eat bread with small amounts of cooked yeast in them. You have to think about it: plants have an efficiency of converting energy to stored nutrients of about 0.3%, which is pretty low. Microbes could go easily to 10 times more, maybe even close to 100 times (but that may be hard to achieve).

May 14, 2018
According to Massa, a good space plant has to be compact and produce a lot of edible food.

I wonder if potatoes would be an option? Apart from the energy density they deliver (i.e. efficient use of growing space) they are very versatile in terms of what you can cook from them. With limited amounts of species being grown in space stations or on long flights I think it's important for morale to have a high variability in meals. Cabbage is fine for a while, but if I compare the prospect of eating cabbage every day to eating potatoes every day I know which I'd pick.

Jul 05, 2018
Great article! The one thing that really helps me with the indoor gardening was the grow lights! That thing is just amazing for indoor plants - take a look

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