Rooting for Space Plants
Author: Sarah Pounders
Overview
Onboard Space Shuttle Columbia in 1997, Leonid Kadenyuk,
Ukrainian payload specialist, works with the Brassica rapa plants
being grown for
the Collaborative Ukrainian Experiment. (Photo credit: Marshal Space Flight
Center - NASA)
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Discovering an efficient way to grow plants in space is critical for
expansion into the extraterrestrial frontier. Space travelers will
need a reliable source of renewable food and oxygen to survive over
long periods of time. Traditional gardening techniques are not a good
match for conditions in spacecraft and space stations so scientists
are challenged with creating new growing systems. Many of these systems
draw on principles related to hydroponics.
Objectives - Students will:
Contemplate the challenges of growing plants in space
-
Learn about hydroponics and experiment with different
hydroponics set ups.
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Brainstorm other ideas for growing plants in space
Standards (Microsoft
Word document)
Materials: Copies of the chronicles
of International Space Station Science Officer Don Pettit from
this Web site for distribution to the class
Background
Soil is both heavy and bulky which – two qualities to avoid when packing
for space travel. How can you grow plants without soil? Try hydroponics.
The word hydroponics actually comes from two Greek words – hydro,
meaning water and ponos, meaning work. With hydroponics, a solution
of water and nutrients surrounds the plant roots, doing the work of
soil. Plants grown hydroponically still have the same needs as those
grown in soil including water, air, nutrients, light and a stable place
to grow.
For more information, visit Exploring
Classroom Hydroponics.
Laying the Groundwork
As a class, read the space chronicles of International Space Station
Science Officer Don Pettit (see Materials, above)
about his efforts to grow plants in space. Use the following questions
to lead a discussion about his experience:
-
What were some of the challenges
he faced in trying to start his seeds?
-
What did he use to start
his seeds? Why did he think it would work?
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What did he discover
when his seeds did not immediately sprout? What did he do to
overcome this new challenge?
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Why did his first batch of seedlings
die? What did he change on the second batch of seeds?
-
Ultimately,
why did his second batch of seeds die? What could he have done
to help them live longer?
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Have students experiment using one or more of the basic
hydroponics set ups detailed in
Step
5 of the Hydroponics Guide.
We suggest beginning with crops such as lettuce, herbs, and houseplant
cuttings, and experimenting with other plants once you have a feel
for the setup.
-
As a comparison, also grow the same plants using
traditional gardening methods in pots using garden soil or a soilless
potting mix.
-
Track observations daily in a journal. Describe and
measure plant growth.
Making Connections
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How did your setup(s) meet
different plant needs? Were there some needs that were not well
met? What did you observe to make you believe that?
-
If you compared
plants grown with and without soils, did you observe
any differences? What were they? What do you think caused them?
-
Where in nature have you seen plants growing without
soil? Did they appear to have specific adaptations to grow in a soilless
environment?
What were they?
-
Can you think of any purposes of soil that
are not fulfilled by hydroponics?
-
How do you think hydroponic growing
could be used in world agriculture? What type of limitations do
you think it has?
-
Would you rather raise a garden hydroponically,
or with soil? Why?
Branching Out
Research some of the experimental systems used to grow plants
in space:
Bioserve Plant Growth Chamber (PDF)
VEGGIE, the Deployable Vegetable System
Ask students to design a space garden of their own that will
provide the basic elements plants need. As they share their designs
with their classmates, have them describe how it fulfills the plants’
basic needs.
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© 2009
National Gardening Association