Hello. I am a junior in high school in a Botany class and I am researching the question “What plants can be grown in conditions outside of Earth, and how do the conditions change the plant?”. I am researching this because I love space, and I have been wondering if future life on different planets would eventually be possible. If so, plants are going to have to be able to grow consistently without Earth Conditions, so I decided to do my final about this topic. If you know anything about this topic, feel free to help me out! Thanks!
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Your current question is so broad, you would have to read a whole library to begin an answer. Try narrowing your question down to something that could form the basis of an experiment.
Ask yourself:
What conditions (“Earth Conditions”) do plants need to grow (water, nutrients, light, soil, temperature, humdity, …)? What is different in space than here on earth (and what conditions differ according to earth geography!)? Then look at which ones you can (and cannot) control, and ask yourself how each of these makes a difference.
You can then start looking at different plants and think about how they might respond; would shade loving plants work better or worse? How do different soils (sandy, loam, clay) affect growth (moisture retention, nutrient availability, …)?
From here you can form an experimental question (what is the effect of humidity on strawberries?), and narrow down your search results to a few dozen articles.
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Thank you for your advice!
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I have decided to change one of my questions to " How Would Differences Between Mars and Earth Impact Plant Growth?". I have research about the differences between Mars and Earth, but I am curious about if plant growth is even possible with Mars’ conditions. Mars is colder than Earth, along with other variables that are essential for plant growth, so I am researching whether or not it would be possible for Sweet Potatoes to grow on Mars.
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Hey @spacenerd, thanks for joining the MARSfarm community and creating a new topic. I consider myself a #nerdfarmer - so I love the name of your account!
Great job pivoting your question based on @webbhm’s advice.
First question
If you live in the United States (and lots of other places around the center of the Earth), thousands of plants can be grown outdoors and dozens of them are produced at scale. When deciding whether to plant something outdoors, the most important thing to consider is temperature, because if it gets too cold the plants will certainly die. To help people decide which plants will thrive where they live, the United States Department of Agriculture (USDA) publishes a “Plant Hardiness Map Zone Map” based on the average annual minimum temperature. If you look at where I live (St. Louis, Missouri) you’ll see that it actually stays warmer in the city (see all the highways) than it does in the rural areas - which means I can plant tomatoes in my garden a week before they can!
Map of USDA plant hardiness zones for area surrounding St. Louis, MO.
Now, if you’re trying to grow lots of plants for food or money (agriculture) then you want to make sure that you’re maximizing the productivity of whatever plants you are growing. One way of doing that is to find out how many “Growing Degree Days (GDD)” the plant you are growing requires in order to reach harvest. Essentially, for every 10F increase, plants double their productivity. For a plant that has to produce something with a lot of calories (like a sweet potato), it requires more GDD than something with very few (lettuce). To help farmers know if there are enough GDD in their region, the USDA publishes a map showing the number of GDD over the last 30 years.
USDA GDD Map
Some plants are worth more than others. People are willing to pay more for fresh fruits and vegetables (lettuce, herbs, tomatoes, cucumbers, peppers, strawberries, etc.) because they are more nutritious and taste better when eaten fresh. These plants are worth so much that companies are investing billions of dollars to build “Controlled Environment Agriculture (CEA)” farms to grow them. CEA is a fancy term that describes high-tech greenhouses/vertical farms, which use technology like hydroponics and LEDs to control the temperature, irrigation, and lighting of the plants being grown.
Examples of companies that use CEA technology on Earth to produce food
If Mars had a “Plant Hardiness Zone” - it would be at least -10. Honestly, it’s a horrible place to try and grow plants. The temperature is way too cold, there’s no rainfall, and there’s not even enough light. That’s why we’re going to have to use CEA technology to grow plants in space. That’s why NASA picks people like Dr. Gene Giacomelli to research what technology and plants should be grown in space. Dr. Giacomelli teaches students who usually go on to work in CEA farms (on Earth), but check out this video where he talks about the Lunar Greenhouse prototype they built using funding from NASA - they learned a lot!
Second question
In an interview Dr. Giacomelli had this say about “The Martian” - where someone actually grows potatoes on Mars: “It was science fiction, of course, but it brought a lot of real science and engineering to all the people - young people particularly. It should have excited a lot of people about the ingenuity, the capabilities that we have for living on another planet 10, 20 years from now. But the real exciting part to me was that we’re working on much of what Mark Watney had to do so he could survive. We’re doing that in our laboratory,”
Let me know if you have any more questions!
If you want to learn more about what plants are best suited for growth in CEA farms, check out this forum post:
I think this is a better question, you have one variable (temperature) and a good constant (sweet potatoes).
You could explore what could be done about the temperature. We grow plants in cold climates here on earth with various types of greenhouses. What could be done on Mars to collect solar energy?
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