This week our plant science lessons are taking a bit of a detour and going on a long trip. In fact, is honor of World Space Week we're investigating growing plants in space.

You may have heard some of the buzz about the new movie The Martian starring Matt Damon (see info and trailer). The premise is that an astronaut is accidentally left on Mars and has to figure out how to fend for himself, which involves growing plants for food under extreme conditions. The movie's popularity makes it a perfect time to get kids excited not only about science in general, but also plant science (botany) in particular.

Background Information

There are many reasons to grow plants in space. The most prominent, of course, is to provide food for long journeys or for colonies on other planets like Mars. Growing plants also remove carbon dioxide and produce oxygen, which can be important for long term survival. Plants may also produce and help regulate humidity in confined areas, can be used to purify water, and/or serve to detect certain environmental toxins.


Microgravity- When in space, people and objects seem to be weightless. The term microgravity reminds us that even in the conditions of space, gravity is still acting.


Tropism - Plants can exhibit directional growth in response to certain stimuli. Examples of tropisms include hydrotropism (growth in response to moisture levels), phototropism (growth in response to light), thigomotropism (growth in response to touch or contact), and gravitropism (growth in response to gravity). NASA has a short video about tropisms.

Resources and Lessons:

There are a number of plant science in space resources and lessons  available from sources online. Let's take a look at a few of them.

1. The University of Florida Space Plants Lab is using our old friend Arabidopsis to study plant growth under microgravity conditions. This video from Science Friday explains some of their goals and findings.

Keep up with their research at the Exploring Space Blog.

2. Wisconsin Fast Plants and Space

Wisconsin Fast Plants® are cultivars of Brassica rapa that have been selected to complete their live cycles extremely rapidly (in about one month). Their fast growth makes them ideal for experiments in space.

Wisconsin Fast Plants® website has a Fast Plants in Space activity resource page, which includes links to:

  • Plants in Space on the International Space Station (see details below)
  • Farming in Space
  • Tumbling in Space activity (investigating gravitropism)
  • Astroplants in Space

Wisconsin Fast Plants® are available online from sources such as Amazon (contains affiliate links)

Wisconsin Fast Plants® Standard Seed, Pack of 50

Wisconsin Fast Plants® F1 Hairless Non-Purple Stem, Pack of 50 Seeds

3. Plants in Space on the International Space Station

In the fall of 2011, a group of agencies* banded together for the Plants in Space experiments on the International Space Station. Resources for the project are archived at BioEd Online, and include a 21-page teacher's guide to download for free. These experiments used Fast Plants®, but could be performed using other fast-growing alternatives (for example, Rapid Radishes from Ward Scientific).

Although the experiments on the International Space Station have been completed, there are still many ways to use the project as a jumping off point for further studies. Watch the introductory video (also available on the website) for many ideas for designing plant science experiments.

*The agencies included Center for Educational Outreach, Baylor College of Medicine, in collaboration with BioServe Space Technologies of the University of Colorado, and the United States National Aeronautics and Space Administration. Funding was also provided by the National Space Biomedical Research Institute.

4. Tumbling Plants:  Gravitropism Experments

a. In the above video from Plants in Space, the narrator suggests investigating the effect of gravity on plant growth by designing a device that rotates the plants every thirty seconds, thus removing the directional aspect. Although it is not completely clear, apparently Dr. Vogt uses a Lego Mindstorms Nxt to program the rotation of the plant.

b. Seed spinner with littleBits and Fast Plants®

In another version of the same experiment, microgravity conditions are simulated by rotating the plants via littleBits electronics combined with snap cubes and a petri dish.

5. NASA's Plants in Space lesson plans

NASA also has some Plants in Space lesson plans. These contain a range of related activities, not just plant science.

Educator Guides available on the website:
•    Moon Munchies Educator Guide (Grades K-4)
•    Packing Up for the Moon Educator Guide (Grades 5-8)
•    Lunar Plant Growth Chamber Educator Guide (Grades 9-12)


Investigating how plants grow in outer space expands our horizons, but it will also help us better understand how plants grow here on Earth. Hopefully the links will inspire you to try some plant science experiments with your children/students.

Do you have any questions or more plants in space activities to suggest? Feel free to leave us a comment.



To see our complete plant science lessons, either visit the plant science category (newest posts to oldest posts) or the plant science section of our experiment archive page (links to posts in order).

For more activities, try our Gardening/Plant Science for Kids Pinterest board.

This week we had two caterpillars on our rush milkweeds.

stripy-2-caterpillarAt first glance they look quite similar.

stripey-3-caterpillarBoth have bands of color and filaments (also called tubercles) that look like antennae.

stripey-2-47Looking more closely, it is apparent that this caterpillar has two pairs of filaments, one pair in front and one pair in back. In addition, its bands of color are unbroken.

stripy-three-68This caterpillar has three pairs of filaments and some of the dark bands have droplets of yellow in them.

Do you know what species of caterpillars these are?

Note on the filaments (tubercles):  These threadlike projections are often mistaken for antennae. Caterpillars do have antennae, but they are only tiny bumps on the front of the head near the mandibles. The filaments vary in length and are occasionally missing.

Caterpillars like these can move their filaments, sometimes in a jerky motion.

Answers:  The caterpillar in the first and third photographs will turn into one of these. The caterpillar in the second and fourth photographs is one of these.



Today we are going back to visit the book Seed to Seed: The Secret Life of Plants by Nicholas Harberd for more insights.

(Image is affiliate link)

The author, Nicholas Harberd, has run into a bit of a roadblock in his research. When he asks his son what he is doing at school, his son tells him he is growing beans in a jam jar, a classic elementary school activity. There's an "Eureka!" moment as Dr. Harberd realizes the importance of these early experiences.

Sprouting bean seeds in preschool or kindergarten is a seemingly universal activity.  Just because it is very common, however, does not mean it has less value. Germinating bean seeds is a significant early introduction to how plants work.

Seed Germination

As you can see from this time lapse video of a mung bean germinating, the process unfolds in a defined sequence.

First, the seed coat begins to wrinkle and the seed swells as water is taken up. If you keep an eye on the center bean, you can see the tiny white radicle begin to emerge first. If you look closely at about 1:00 minute, you will see the end of the radicle, which is still white, starts to produce fine threads. Those are root hairs. At the same time, the part closer to the seed is also elongating and beginning to green up a bit. That is the hypocotyl, which is what supports the cotyledons as they rise about the surface. As the hypocotyl continues to elongate, the cotyledons begin to emerge from the seed coat. By 2:00 minutes, the cotyledons are beginning to open and the first leaves or plumules are beginning to show. The stem-like structure that will eventually arise between the cotyledons and the plumules is called the epicotyl.

Brittannica Kids has a good graphic showing the bean germination process.

Activity 1. Sprouting Bean Seeds (Observing and Experimenting)

This activity can be done any number of ways. I will give instructions for one way and links to other sites with good instructions.


  • Dry bean seeds, especially big types like lima beans, available in the grocery store in the dried food area. Dry bean soup mix is another fun source of different types of beans, and some contain barley or other grains.
  • Paper towels
  • Water
  • Plastic sandwich bag or paper plate covered with plastic wrap
Bean Soup Mix
Bean soup mix is fun to sprout.


Wash hands before starting to cut down the chances of mold.
1. Wet two or three paper towels until damp, not dripping wet. Lay the towels flat.

2. Place enough beans for all the children on half of the towel. Fold the top over, creating a sandwich with the beans inside.

3. Slip the paper towels into a plastic bag and close, or onto a paper plate and cover with plastic wrap. The plastic will help prevent the towels from drying out too quickly.

4. Check the beans every day to see how the beans germinate. Depending on the temperature, the beans should start to swell and a root start to form as early as 24 to 48 hours later.

Add enough water to keep them damp if the towels begin to dry out.

bean-soup-mix-sprouting5. Have the children draw the beans each day and measure how much each part has grown, if possible. Record the results.

6. Allow the children to experiment with the seeds. They might want to remove portions of the plant or seed or change the growing conditions (moisture, light, add soil) to see what happens.

Extension: Compare seeds with two cotyledons with seeds from plants like barley, corn or wheat, which have only one. See What is a Seed for dissection instructions.

Related links (some sites have ads):

Activity 2: Germination Test for Older Kids

Ever have a pile of leftover seed packets tucked away in a cupboard somewhere? You know, the ones with the “Packed for 2009” stamped on them?



If you are not sure whether the seed is still viable or whether planting it would be a waste of time, there’s an easy test to find out. It is called a germination test.

Pull out your old seed packets. Note: check the packages carefully to see if the seeds are treated with pesticides, such as fungicides or insecticides. Avoid handling pesticide-treated seeds.

For each packet you and/or your children want to test, gather the following:

  • Paper towels
  • Either paper plates and plastic wrap /or zip-loc style plastic bags
  • Water

Wash your hands prior to starting and try to keep everything as clean as possible.

1. Prepare a separate damp paper towel for each different seed packet.

2. Select 10 seeds from each packet you want to test. For example, you might have 10 marigold seeds and 10 corn seeds.

3. Lay the 10 marigold seeds on a damp paper towel and fold it over. Then either lay the towel on a paper plate and cover with plastic wrap, or slip the damp paper towel into a zip-loc bag. Repeat for the 10 corn seeds or whatever kinds of seeds are in the rest of the packets.

germination test

3. Come back in 24 hours and 48 hours and look for the tiny root (radicle) poking out of the seed, a sign that it is germinating.  Count how many seeds germinate and how many do not. Certain seeds, like carrots, take a long time to germinate (up to 2 weeks), so keep them moist and don't give up on them right away. If no seeds germinate after two weeks, then perhaps it is time to invest in a new batch of seeds.

You can calculate the percent germination by dividing the number that germinated by the number you set up. For example if 9 seeds germinated out of 10, then your percent germination = 90%. If only 5 germinated out of 10, then the percent germination is 50%.


Do you have any questions or seed germination activities to suggest? Feel free to leave us a comment.

To see our complete plant science lessons, either visit the plant science category (newest posts to oldest posts) or the plant science section of our experiment archive page (links to posts in order).

For more activities, try our Gardening/Plant Science for Kids Pinterest board.

Botanical Interests supplies high quality seeds (Image is affiliate link).