Episode 17: The Science Behind Growing Food in Space

Episode 17: The science behind growing food in space

Dr. Bruce Bugbee, Professor of Crop Physiology and Director of the Crop Physiology Lab at Utah State University, discusses his space farming research and what we earthlings can learn from space farming techniques. Find out what happens to plants in a zero-gravity environment and how scientists overcome the particular challenges of deploying measurement sensors in space. He also shares his research on the efficacy of LED lights for indoor growing.


Dr. Bruce Bugbee is a Professor of Crop Physiology, Director of the Crop Physiology Laboratory at Utah State University, and the President of Apogee Instruments.

His work includes collaborating with NASA to develop closed life-support systems for long-term space missions. He’s been involved with the development of crop-growing systems for future life on the Moon, in addition to in-orbit or in-space shuttles. He’s worked on projects for Mars farming, including the use of fiber optics for indoor lighting, And as a part of this research, he was involved in the creation of the NASA Space Technology Research Institute’s Center for the Utilization of Biological Engineering in Space (or CUBES). 

Dr. Bugbee also has long been a critic of the use of indoor farming as a means of solving food shortages, due to the large amount of electricity needed to provide light for photosynthesis. His recent work in this area has included studies into the efficacy of LED lights for indoor growing. (Credit: Wikipedia)



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Hello everybody, and welcome to We Measure the World, a podcast produced by scientists, for scientists.

We’re working with colleagues at UC Davis to put genes in plants to produce thyroid stimulating hormone. And this is mostly in lettuce. And that helped, we are hoping that will help increase bone density in people living in space. But this is genes that we’re inserting in the plants to help the plants synthesize valuable hormones that we’re going to need more of.

That’s a small taste of what we have in store for you today. We measure the world explores interesting environmental research trends, how scientists are solving research issues, and what tools are helping them better understand measurements across the entire soil plant atmosphere continuum. Today’s guest, Dr. Bruce Bugbee, is a professor of crop physiology and director of the crop physiology laboratory at Utah State University, and the President of Apogee Instruments. His work includes collaborating with NASA to develop closed biological life support systems for deep space missions. He’s worked on projects for Mars farming, and as part of this research, he’s involved in the development of the NASA center for the utilization of biological engineering and space or cubes. Dr. Bugbee also has analyzed the use of indoor farming as a means of solving food shortages, with regard to the large amount of electricity needed to provide light for photosynthesis. His recent work in this area has included studies into the efficacy of LED lights for indoor growing, and today he’s here to talk to us about his many fascinating research projects. So Bruce, thank you so much for being here with us.

Thanks, Brad. Glad to be here.

So first, we wanted to start off just by getting into your background a little bit. How did you first get involved or get interested in a career in crop physiology or plant physiology,

you would think that I grew up on a farm or something, you know, got interested in plants that way. But I grew up in a very rural area, but wasn’t on a farm. In college, I took a botany class, it was at the University of Minnesota, we were germinating different kinds of seeds. And I just got so fascinated by how they grew. And that one thing led to another and I I switched from engineering, which is what I started in to plant biology as an undergraduate. And that that just kept going on pretty soon people are instead of you paying tuition, people are paying you to work and and there I am 40 some years later, still still doing the same things. But it all started with a botany class and in as an undergraduate in college.

And so going from that undergraduate there in in that botany class, how did your I guess academic career or your postgraduate research evolved from undergrad botany class onward through your PhD and beyond?

Once I discovered my passion in plants, I wanted to learn a lot of stuff fast. And I remember when I changed majors, and there was a semester I took 27 credits, all in Plant Biology, because I just wanted to learn it all at once. It’s all I did was studied this stuff. And it grew and and then I decided I wanted to go to graduate school. And at the time, I got accepted at the University of California Davis for a master’s degree. And I was really interested in vegetable crops. So I went there and studied more physiology, and had more opportunities to do research. And then I got really recruited by a professor at Penn State University to come there for a PhD. And work on a project that was energy efficiency in greenhouses, how to get use less energy in greenhouses, because they’re just such massive energy users. And that was my PhD. And then I have positioned came up at Utah State University, Faculty position. And this is my first job after graduate school. And you never think you’re going to stay in one place. But things evolved. And here I am, over 40 years later. And I guess that’s a huge thing for me is, early in my career, I was able to get funding from NASA through a competitive proposal. And that was just perfect for me because of really intensive control of the environment to optimize plant growth. And the beauty of working for NASA is cost is no object. It’s all about the weight of the system and Doesn’t matter if it’s expensive, what does it weigh? Because we have to launch it. And of course, then you recycle everything, because weight is such a big deal. So that that led to studies with NASA.

How long ago was that when you first got involved with your research and connections with NASA?

Yeah, it was it was 1981 When I came here and started working with NASA, so more than 40 years ago. And it’s been almost continuous. Yeah, yeah, well, yeah, it’s been almost continuous funding, that that whole time, just different options to have opportunities to write proposals to different groups in NASA to solve different kinds of problems, all centered around the use of what you mentioned in the introduction, biological life support, which means growing food, and the plants automatically make the oxygen for the people, and they automatically purify the water. So if you grow your own food, you get all these other things for free. And if you don’t grow your own food, Well, number one, you got to bring a lot of bag lunches into space. And number two, you have to have some system to purify the water, you have to have some system to split, split water to get oxygen. Those are expensive systems. So NASA has increasingly seen the value of biological life support for long term missions in space.

I’m sure that there are a lot of different side projects that went along with that. But with everything focused on plant growth, and germination, etcetera in space, or at least in micro or zero gravity, how do plants respond in general to an environment such as that?

Yeah, it’s a great question. I get asked that question a lot. And the quick answer is the plants do a lot better than the people. People lose, we lose calcium from our bones. And it’s a problem, you’re in space long enough. You can’t come back to a one G gravity environment and just walk around, you just can’t do it. It takes weeks and even months to have to reestablish your bone mass and equilibrium back in the earth. Plants don’t have that problem. They grow towards the light. So there’s no problem there. The roots grow away from the light. There’s some evidence that less gravity is even good for plants. They don’t have to make so much lignin to stand up tough and tall. Gravity is a stress on plants and you take away they grow faster. So there’s no way there’s a lot of challenges to growing plants without gravity, but they are indirect challenges there. It’s not a direct effect. Here’s a perfect example. And it’s really good for for the people using METER Group equipment. How would you water plants in space? Well, I just pour the water on the pot. Ah yes, but the excess water does not drain out of the pot. It just stays in there. And now you flooded the plant and I have to apologize to the taxpayers we’d spent 10 or $20 million of your money flooding plants in space because we it took us a while to hear them out. And now we use TDR probes we use lots of sensors and we precisely water the plants like literally with a syringe sometimes we never over water the plants it but it took us a while to get to that point. And we’re still refining the systems. We want the media up there we can do continuous cropping in year after year the same media so we call that no till farming in space.

Along with that to the plants have any issues in for instance, like the uptake of water or nutrients or you know carbon dioxide or other things like that with in zero gravity or microgravity.

The short answer is no, they do not. But as you get into this a bit more, you realize a hot air rises on Earth. And that’s pretty, pretty simple concept. But hot air rises in micro turbulence like a leaf gets warm, and the air around the leaf arms in it and it starts to float up because it’s warm air. That doesn’t happen in space. If air is different temperatures. It just sits there. It doesn’t separate So the solution to that is we have to use a lot of fans to blow the air around. But warm air doesn’t rise. To emphasize that point how interesting this is. Here’s a question I ask PhD students sometimes on comprehensive exams. What would happen if I lit a candle in space? What would happen to that candle. And the first thing is, well, nothing it it burns just like it does on the ground. But then you go, Wait a minute, a candle burns because the hot air rises, and it draws in fresh air from the bottom, and the fresher has more oxygen. And that’s what makes the candle burn, the hot air rises and it gets oxygen. That doesn’t happen in space. And so in fact, you light a candle in space, and it will go out, it’ll self extinguish, because it can’t get enough oxygen. Now, in reality, if you have any kind of fans, it’s fine. But if you have to absolutely no fans, the candle won’t go out. Because the hot air doesn’t rise, and it doesn’t draw fresh oxygen. And so now imagine that same concept, but applied to the leaves of plants where the bright light is shining on him and they get warm, and the heat doesn’t rise away from the plants. These are fascinating challenges, but they’re indirect effects of gravity on the planet.

Interesting. I was also wondering about the effect of, you know, transpiration or evaporation on that system as well.

In the case of transpiration, what we have to deal with is a closed system. So we’re not blowing air. I mean, on earth, the wind, plants put water vapor in the air, the wind blows it away, and it falls as rain and somewhere else. But in a closed system that air gets more and more humid. And then the plants transpiration stops, because there’s it’s 100% humidity. But that causes disease. So we have dehumidifiers, and we condense the water out of the air. But you have to have fans and dehumidification so that the plants can keep transpiring water. But that’s a closed system that doesn’t have to do anything with gravity, it’s just closed. And indoor agriculture on earth has precisely the same problem. What do you do with all that water vapor? When you want to recycle the co2 and recycle the area, you have to condense it out of the air?

You’d mentioned earlier about spending taxpayers money on flooding pots of plants. You also mentioned that you had quite a few different sensors that you were involved in these projects. What were some of the sorts of variables that you were looking at with these sensors?

Oh, we mean, obviously we do the obvious things like temperature and humidity and especially light level. I mean, that’s that gets into part of the reason I founded Apogee Instruments, better sensors to really rigorously quantify the light that plants get. But and you take the root zone environment, and we want to very precisely measure the amount of water in the root zone. And on earth. It’s sort of the excess water. Like I said, it just drains out. But we don’t have that we we have to be super careful not to overwater. So, so we use all the latest technology to monitor all of those environmental variables. One, for example, is infrared sensors to measure temperature of the leaves. Now that’s done on earth too. If the leafs get hot, that means something’s wrong with transpiration. They’re not cooling by evaporation the way they normally would. So if we’re measuring leaf temperature, we can very quickly look what’s what’s going on what’s wrong right now, with these plants. We like to see the plants stay nice and cool, because that means the soulmates are open and they have a healthy and robust transpiration rate. One of the things that’s a little bit more cutting edge is spectral imaging, continuous imaging of plant size and plant color. And this gets into some of the more cutting edge work on that we do with with NASA. real time monitoring of plant health is really what it amounts to with with spectral imaging.

Along with that kind of moving from Earth into orbit over to Mars. Can you tell us a little bit about some of your research into the theories involved in farming on Mars?

The biggest challenges on Mars are closure, recycling everything. It’s that’s the biggest single thing. You know, imagine? How would you live in your house? If you didn’t have garbage pickup? What would you do if you just don’t have it anymore. And all of those ways, you don’t even have a sewer system, all of those wastes have to go back, and your whole yard is growing food, all of it, we soybeans, everything you need to grow, not just tomatoes and lettuce. That’s that’s a pretty good analogy for our challenges. Just take composting, for example, we 80% Even more than that 85% of the nitrogen we take in every day, leaves our body in urine. And it’s a simple molecule, it’s urea. And urea is the most widely used nitrogen fertilizer in the world. And we do nothing to recapture it, we just send it down the sewage system and goes into the rivers. And then and then with great expense, we refix nitrogen from the air. And it’s not going to happen with NASA, you got to capture that urea and put it right back on the plants and make sure that you don’t have microbiological issues. It’s so that’s a really fascinating thing. That’s something we’re very actively working on. And when I think about it, it’s sort of tragic that we don’t try to recycle the nitrogen in the urine, and of the whole world population. It’s it’s not that hard to do, you have to separate it from salt. But I can see in the future low cost systems to capture urine and separate it. So that nitrogen is available for agriculture.

Right? I mean, because this is one of the things from what I understand we’re nowhere near having a long term self sustaining ecosystem on Mars. But the ideas that are being you know, germinated here on Earth, they might actually help us here on Earth before they ever help us on Mars. There’s quite a few different spin offs, where they’re trying to do one thing. And then just by happenstance, this other thing comes to fruition.

On that note, Brad, I think both Gaylon Campbell, and myself, are giving an invited talk at the agronomy, society national agronomy, society meetings this November in Baltimore. And the title is that of the symposium is the value of serendipity in science. And it’s when you’re looking for one thing and you find something else, you weren’t really looking for that, but you would have never found it if you weren’t looking in the first place. And I think it’s really interesting that both David and I are talking in that been asked to talk and that symposium,

with your work with NASA, whether on Mars or elsewhere within those projects, what are some of the key takeaways that you’ve had?

I would say one of the significant recent things, was realizing that LEDs have now become so efficient, they caught up and passed solar fiber optic systems for providing light for photosynthesis. Until about as recently as five years ago, we were using great big parabolic mirrors and focusing light and bringing it inside with glass fibers, no electricity, just optical systems. And that was the state of the art for NASA. And they were putting a lot of money into that. And then we with a lot of help from mechanical engineers, we’re able to show that solar panels and LEDs have become so efficient, they caught up in past these big solar fiber optic systems. And that’s that’s really fundamentally changed. Huge research direction for NASA. And it opened a lot of doors now we can get all different ratios of colors of light, manipulate, where we put the light, how much we put in there and what colors it is those kinds of things. That was a significant thing. And that research is going to be played out in more food production under electric lights on Earth. Big partly because of this research. This is a little more technical, but we’ve never considered far red light to have any value for photosynthesis. And through a series of studies with LEDs we showed that far red light is valued for photosynthesis for plants, and this is quite a big finding. For understory plants and forests, which are enriched with FAR red light, it allows us to use far red light, to manipulate plant shape and help plants grow faster. It changes how we think about the colors of light for photosynthesis. That’s another quite a significant breakthrough that happened. As a result of our NASA funded research.

You talked about how money really wasn’t a problem when it came to NASA funding. But were there other challenges that you ran into?

Yeah, let me clarify the money thing, the money is always limited. It’s not like we get an unlimited research budget. What I meant to say with what something costs, it’s way less important than what something weighs when you launch it into space. And if titanium is lighter weight, than aluminum it’s a no brainer. I don’t care what titanium costs, just because it is so expensive. To launch it into space, NASA funds, the things that they need to, to help us develop a life support system. And certainly miniaturization is huge. But commercial companies are already doing that. NASA doesn’t have to further fund that research. With some exceptions, they let commercial developments go. NASA is not funding research on making more efficient LEDs, for example, because that’s already happening with all the big led companies, they’re working very hard to make them more efficient. lumileds is the company it’s the biggest American company making LEDs. There’s Chinese companies, Korean companies, European companies. lumileds is the company in the United States. So we worked with them to make lights that were just super efficient for our plant growth chambers. And they’re outside my office now running in chamber growing plants. So that was a demonstration that we could assemble off the shelf technology into something just highly efficient to grow plants. Now, those LEDs were expensive. But they’re more than 80% efficient. I mean, it’s just amazing. In turning electricity in photosynthetic photons. And as an example, our previous best technology for turning electricity and delight was high pressure sodium lamps. And they were about 40%. So Whoa, we’ve doubled that. With the advent of Le. It didn’t happen overnight. There’s lots of incremental improvements, but it’s a it’s a stunning advance for for Well, all of humanity really for human lighting for plant growth lighting.

You mentioned 80% efficiency, what then could be the theoretical limit or threshold for LED efficiency?

Well, theoretical limit is 100%. But it’s super hard to get 100% I think we will inch this up to 90% probably in the next several years. And then the increments past that are going to be very difficult. 91% 92% You know, it’s going to be gets increasingly hard as you approach 100%. But man, I mean, five years ago, we thought, Oh man, it’s gonna take a long time to get to 80% efficient. Well, we’re there now. And the manufacturers are all in competition with each other to push the envelope on this.

I guess what you’re describing then is kind of a, you know, a sigmoid curve of efficiency from original fluorescence to sodium to LEDs and onward did

yeah, and on that exact note I I’ve got quite a few videos online of different topics. I mean, if you search for my name and some topic bugby agriculture, you’re going to see lots of videos, some of them are on the efficiency of LEDs, and how it’s the historic change that sigma curve that you’ve talked about.

How did your research with LEDs get started? Was there a particular specific project that you were working on that was focused on LEDs? Or did it just happen to come along during your journey there?

20 to 25 years ago, the first LEDs we’re getting started, but at least the first that we used for commercial agriculture. And they were being used by NASA at NASA Kennedy Research Center. And we didn’t have access As to him yet, but we used a lot of filters under regular lights, to look at the effect of ratios of colors, and published some papers on that, then we could predict that when the LEDs got invented, here’s how we could be using them. And so then when they did become more favorable, then we started buying them and, and really, the lighting manufacturers were donating their prototypes to us for research. So then we ramp up pretty fast with manipulating colors of light to improve plant growth. That will say there’s some effect of colors of light on photosynthesis. But the big effect of colors of light is on plant shape. We can make plants tall and thin, we can make them short and fat, with colors of light. So there’s a much bigger effect of color of light on plant shape than there is on photosynthesis and direct effect on growth.

You talked about the far red being able to improve the photosynthetic process. Are there interesting byproducts from the other end of the spectrum, so to the to the violet ultraviolet.

Yes, we use blue photons, and even violet photons, and even ultraviolet photons, to help keep plants compact. And it also tends to make them more rugged, can make them more disease resistant. If we can use UV to help reduce disease plant leaves, but the most efficient LED is red. And reds, the opposite color of green plants are green. So those red photons are very well absorbed by plants. So we give plants a lot of red photons. And then we add in the other colors to the red to get the desired effects. And then I say a lot 80 to 90% Red photons. And the rest is all the other colors, we add in green. So the people can see the plants. If you don’t have green, you can’t see subtle nutrient disorders. You can’t diagnose the plants. So we get green for the people. So he can see him. And then the plants use the green just fine. But they are not efficient. There’s no efficient green LEDs. So we have just enough for the people.

Is it plant dependent? Number one what those desired characteristics are? And is it plant dependent, the variety of colors that you’re getting?

Yes, it definitely is dependent. It may be I could say not as much as people think that but it’s still dependent. And then we give a perfect example of that. If we add far red photons, or far red light to leafy greens, the leaves get bigger and thinner. If we add far red light to tomatoes, the plants mostly get taller. And that’s bad. We don’t want tall plants. So there’s a case where the red is really helpful and where it’s where it’s not helpful at all. There’s a lot of species differences in sensitivity that colors of light for photosynthesis, it’s almost all the same photosynthesis, the pigments are so similar. There’s not very much species difference for photosynthesis. But there’s huge differences for plant shape.

What do you see the next generation of LEDs? What will they look like? Or how will they perform in your estimation?

Well, first of all, the very big improvement will be to get an efficient green LED for human lighting. And whoever figures that out is probably going to get a Nobel Prize, because, a lot of smart people are working on this to get an efficient green LED. So far, we don’t have it. We have efficient blue, and we have efficient red, but not green. So there’s a big breakthrough waiting to happen. After that, it’s multiple incremental improvements, more reap greater reliability, greater longevity, lower cost. Those all help bring LEDs into the marketplace. And I mean, at some point in the near future, we’re probably going to have building codes that say your building has to have LEDs. You can’t use an old those older technologies of lights.

There is that associated cost that even though we might be more productive when it comes to indoor controlled environments growing there does come a cost with the electricity that’s being used. I was wondering if you might be able to speak to that a little bit of that cost. Well, we’re increasing production, we’re increasing crop yield, but at the same time, there might be a global cost to that.

Yeah, It takes a lot of light to replace the sun, the sun, it comes up for free every day, it’s very bright, we get a lot of photons for free from the sun. So now you just think I’ll grow plants indoors and use electricity to replace the sun. And it’s, it’s like 50 cents per square meter per day to replace sunlight. With electric lights, it’s, it’s enormously expensive. So that’s a problem with thinking, we’re suddenly going to grow the world’s food supply indoors, we got to have a super cheap source of energy for that to happen. And that hasn’t been invented yet to do that. And meanwhile, the sun’s fine, just directly. Now consider that if we grow wheat, you can grow wheat anywhere in the world, and harvest it and store it and ship it anywhere else in the world. And if you eat it a year later, it’s still just fine. So in the case of wheat, we’re going to grow wheat where we can use free sunlight to grow it, and we’ll store it, and we’ll ship it to where we need it. But now think about lettuce. You gotta grow lettuce where you eat it. And we grow lettuce in southern Arizona, and ship it to Manhattan all the time all winter long. But what if we could grow it there in the winter with electric lights. And that’s the vision to be able to grow very fresh vegetables, very close to where the consumers are, to where they’re eaten.

I know from our perspective here, METER Group, and from what I’ve seen, we have seen a lot of these new up and coming vertical farms in and around big cities is that something that might be necessary supplement to our outdoor grilling?

Well, I don’t know, but necessary, but helpful. Here’s an example, if if we grow really fresh leafy greens, maybe we can get people to eat more salads. And if people eat more salads, there’ll be less cancer. So maybe we can make progress on cancer by growing leafy greens, fresh leafy greens. That’s something that we don’t think about. But here’s another example. Northern Utah is in a very arid climate, and we’re already out of water to grow plants in the field, we have beautiful fields, but we can’t grow a crop, because we don’t have the water. If we grow plants indoors, we can recycle the water, you can it’s higher humidity, you can condense the water out of the air and recycle it, just like NASA does. And now we can grow a lot of food on a very tiny amount of water. So I think that’s coming for indoor agriculture, that we’ll be forced into doing that, because we’re out of water.

It would be good to try to change the culture of of humans and human consumption, talked about eating more leafy greens, and that would help with cancer and other things. Is it something where we would definitely need to be moving toward sustainable agriculture, but then also the types of crops that were growing where we can focus on like you said more on the wheats, and maybe Rice’s or other things, as opposed to corn or other some of these other crops that take up a lot of water, but may not necessarily help in human health.

It’s something like 98% of the corn in the United States is fed to animals, eggs and cattle. And then we eat the meat, and meats really tasty. We all like it, but boy, it’s hard on the environment. And there’s a case where small changes in the diet can have big environmental impacts. Just because you think about all the corn and beans grown across the Midwest. A very tiny fraction of that is for direct human consumption. It’s for animal agriculture.

What do you think then, as scientists or those in the academic community? This is something that we ask a lot of our guests, how can we better communicate to the general population, our findings, our research, or ways that might better improve our community, our environment or the world in general?

I think you’ve got to stay very modest about what you know. It’s just a scientific principle. Most graduate students, when they have the finding, they write I have proven this. And then the major professor crosses that out and saying no evidence for it. It didn’t prove it. And so that concept is really important for scientists. And when somebody asked me, Do you think I should plant at the full moon? I don’t say you’re crazy. I just say, well, we don’t have any evidence that helps that I didn’t tell him they were wrong. We just don’t have any evidence that helps. And so that kind of thing. And people drive me they go crazy. They just tell me yes or no, Should I do it or not? And science isn’t like that. It’s not always black and white. We we go by the evidence. And some things we have. I mean, here, just smoking caused lung cancer, that really simple question 99.9% of the people’s way, but, of course, it does. Really well, my uncle lived to be 98. And he smoked all this life, that we don’t even know the mechanism by which there’s smoking, smoking is surely associated with bad lung cancer. But we don’t understand the mechanism. And there’s exceptions to that rule. So it’s, it’s very highly correlated with lung cancer, but we cannot say it causes it. That’s a that’s a key difference in science.

Along with that, as well as I think how science is depicted in the mass media, so in films, TV, other things like that can have a big impact. This is tangentially related back to farming on Mars, where you have tons of science fiction, movies, TV shows, books and other things. Very few of them really get into the nitty gritty about life support in deep space, and our long term trips, or, you know, how do they generate the biodiversity needed for life or other things like that? The film, The Martian does a relatively good job at getting into that, because it’s part of the plot, it’s there. And it’s necessary, are there things that that we can take from what we are learning about, you know, farming, whether in space, or on Mars, and then teach that or share that with the public to then help change their minds on certain topics.

Maybe back to the case of that nitrogen in urea, making people understand that can be completely safe. In your urine is not something it’s a valuable product, it’s not something you want to just get rid of you want to recycle it. Just that simple thing. So psychologically, getting people past those certain kinds of phobias. A big part of NASA, surprisingly, is Psychology. How does it change people when they grow their own food? For most people, it’s a great joy. It’s not a burden. It’s a deeply satisfying employee, do I think we’ve lost that? When somebody else grows the fruit don’t ask me to grow or anything. And along with that, satisfaction of growing your own food is gone, too. And in space, yeah, eventually we’ll have people that are specialized farmers. But boy, it’s at first it’s going to be all hands on deck, everybody is going to be helping grow the food. And I think they’ll embrace it. And in fact, they have I mean, I’ll tell you a famous story. 30 years ago, it was a Russian cosmonaut, and he’s a physicist, and he’s flying on the Russian Mir space station. And they said, We’re gonna do some experiments on germinating seeds. And you’re in charge, you need to germinate the seeds and take measurements on the seeds, how they grow. And he said, No, no, no, I can’t grow plants. I don’t like to grow plants. Don’t ask me to do this. And they say, it’s not a choice, you were going to do this science. And you have to do it. So he goes up there. And he said, the first week, he’s grudgingly taking his ruler and making these measurements. And then the next week, he’s spending more time on it and more time on it. And a couple months went by, and he’s spending all his time measuring these plants collecting intricate data. And they said, you could making so many measurements on the plants get back to work. And he came down after I think he was up there for like eight months. And he said long term spaceflight without plants is impossible. And he was talking about the psychological value of things in space.

What are some of the other issues that you hope to overcome or other things that you’d hope to learn about? As you progress in these projects of farming and growing and space?

At a very fundamental level? The mechanism by which the cellular mechanism by which plants perceive gravity mean all plants grow vertical? And how do they tell which way is vertical? You know, you plant them on a side of a mountain, they don’t go perpendicular to the ground. They grow straight up. How do they know to do that? Right? We don’t know yet. We’re studying it with with flying glance. But they, you know, we know about humans it’s it’s our inner ear. That’s how we tell which way is up. But how do plants do that we don’t know yet. So that’s that’s a real fundamental science question. That’s just really interesting. That is being studied with the help of NASA funding, understanding how plants perceive colors of light, and how it changes their growth is that’s another big area. We’ve made a lot of progress on that in the last six or seven years. But we’re still working on that. How can we manipulate plants with colors of light. And it’s not just colors, but intensity of light, too. And it’s not just color and intensity, it’s timing, how long should the day be? And if we get color lights, or we give them a different color, at the end of the day, and the beginning of the day, these are all questions that are in front of us that we’re working on to optimize plant growth. And if we optimize plant growth, we optimize footprint, and the whole system gets more efficient. And if that system gets more efficient, then we can use it on the ground to

now for a potential self sustaining ecosystem, is there a minimal biodiversity for the plants that you would need to take or to grow in order to sustain human life in space?

That’s a very interesting and controversial question. If you ask the engineers in NASA, they would say, half a dozen food crops that’ll do it, you know, I can eat potatoes, and I can eat beans, and that’s good. Maybe tomato know and then, and then you go across the road to the nutritionist, and they tell the engineers, are you crazy, we need at least 1000 different kinds of plants to have a balanced diet. And those are the two extremes. And we really don’t understand exactly how many different things we’re going to need to grow, you know, we’ll bring vitamin pills. The more things the better. If you get too many things, the system is less efficient. And some of those things you can’t store you have to grow and fresh. So that’s in front of us too. But how diverse does a diet have to be? People we don’t realize how many different kinds of food products we eat an average day, the products of maybe literally 1000 different kinds of plants. If you start reading the fine print on all the jars of things and cans, and there’s a lot of things in there that are in the diet, we don’t know how many we can leave out and still have a good diet. On this note, one recumbent. We’re working with colleagues at UC Davis, to put genes in plants to produce thyroid stimulating hormone. And this is mostly in lettuce. And that helps we’re hoping that will help increase bone density and people living in space. But this is genes that we’re inserting in the plants to help the plants synthesize valuable hormones that we’re going to need more of,

would edible fungi be a viable product for deep space?

Absolutely. Everything really is on the table. And some things have higher yields than others that are more efficient. And some things are more stable part of the diet. Two things for sure. We need a lot of our rice and wheat. Those are a big dietary staple. And then we need beans to have high oils and high lipids in her diet. But those are beans, it could include peanuts, soy beans. And so those are the staple crops. And then we start to add in all the diversity of vegetables that are really a key part of diet. But there’s an awful lot of vegetables.

Is there a necessity for microbes within soils or soilless media to help with plant growth? You talked about recycling your human waste and being concerned about microbes within that? Are there good microbes that we want to be able to explore as part of farming and space?

Absolutely. And we call those our microbial partners mean, it’s essential to have me what did I read the other day, there’s more different types of microbes in humans than there are stars in the Milky Way. It’s just a striking, we’re full of all these microbes. And they’re good microbes, they help us digest food. They help us do all kinds of things. And plants have a whole host of microbial partners that help them grow well. And so certainly we’re looking at trying to enhance that synergism between the plants and the microbes.

Is there anything that you would like to share, you know, new research avenues that you’re searching for or anything that you’d like to share? With with our audience,

we are getting some funding in my laboratory from METER Group. And it’s to use the TEROS sensors to more precisely water and fertilize plants in controlled environments. So there’s that nice synergism. I mean, that’s us interested in that. And METER Group makes this technology. So we bring them together in a in a high, very high input agriculture to optimize them growth, and it funds a graduate student to study this. Everything’s about all the works done by the graduate students in this lab. So it’s, and a lot of the funding comes from commercial people, that one optimize something for agriculture on the earth.

All right, our time’s up for today. Thank you again, Bruce, for taking your time to share your passions, your projects with us. And if you in the audience have any questions about this topic or want to hear more, feel free to contact us at metergroup.com, or reach out to us on Twitter @meter_env. And you can also view the full transcript from today in the podcast description. That’s all for now. Stay safe, and we’ll see you next time on we measure the world.

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