Seeds have a life span. Their shelf life depends on the variety as well as storage conditions. Seed companies use germination tests to insure the quality of seed farmers and gardeners buy. Gardeners who often buy more seed than they can use in one season also conduct germination tests on stockpiles of old seed to determine its viability. Test results predict the percentage of seeds that will germinate in the garden.
Conducting a germination test requires both simple and sophisticated mathematical mental maneuvers. Teachers involve students in making seed germination tests to help them visualize and apply math concepts related to set, operations of addition and subtraction, fractions, ratio and percent.
Seed Germination Test
A simple seed germination test uses old seeds, paper towels, water, and a ziplock bag or petri dish. Pumpkin seeds are excellent choices because they are easy and fast to germinate, familiar to students, and large. Good alternates include old bean, pea, sunflower, squash, cucumber, and radish seeds.
The following germination test instructions may be adapted for individual students or groups of students:
- Count out and line up ten pumpkin seeds on top of a damp paper towel.
- Roll up the paper towel with seeds inside and place all in a plastic ziplock bag. Zip the bag closed.
- Label the bag with date, seed variety, and student or group’s name.
- Leave the bag at room temperature out of direct sunlight.
- Make a germination peek every 3-4 days to see what is happening and if the towel remains moist. Close bag up well each time.
- Open the bag after 7-10 days from the starting date and count the number of sprouted and unsprouted seeds.
Mathematical Seeds
Each student or group started with a set of 10 pumpkin seeds. The germination test created two subsets, sprouted and unsprouted seeds. Where does instruction go from here?
For early elementary students the seed germination test is an introduction to sorting and sets. The initial ten pumpkin seed sample can be counted and sorted into sprouted and unsprouted seed sets. Children can arrange the sprouted vs. unsprouted seeds in vertical column bar graphs creating a visual of the relationship between the two sets.
Additionally, the seeds can be used to introduce fractions by modeling a denominator with ten pumpkin seeds representing the original set and a numerator with sprouted or unsprouted seed. Separate the numerator and denominator seeds with bright yarn.
In primary grades the germination test provides practice of simple addition and subtraction facts. Students can create addition and subtraction problems represented by their sprouted and unsprouted seed data for peers to solve.
For older elementary students the germination test retrieves past mathematical experience to move to more advanced concepts. Students now must compare the number of sprouted seeds with the number in the total sample by writing a ratio. For example, if 7 seeds of the 10 sprouted, the ratio would be written 7:10 or the fraction 7/10.
Then move students to write the fraction 7/10 as a decimal fraction or .7. Since percent is expressed in hundredths, have students express .7 in hundredths or .70. It may be necessary to include the following step: 7/10 x 10/10 = 70/100. Then, the student calculates 70/100 as 70%.
Repeated experience with decimal fractions will allow the student to automatically take an expression like .70 and multiply it by 100 to yield 70% and state that the germination rate of his sample is 70%.
Next, have students determine the percent of seed that did not germinate using two methods. They may follow the same procedure used to arrive at germination rate to determine percent of nonviable seed. Secondly, they may subtract 70% from 100% to determine 30% of the seed that did not germinate.
Extension Activities with Sprouted Pumpkin Seeds
Pumpkin seeds are science manipulatives too. In spring, a germination test could double as a presprouting preparation for planting the schoolyard pumpkin patch.
Anytime of year sprouted seeds can give children concrete experiences to extend vocabulary and enhance contextual meanings of plant concepts. They view the embryonic root or radical, the first part of a seeding to emerge. As seedlings emerge from the seed coat, the protective function of the tough coat is observed. Some germination tests reveal the cotyledon or embryonic seed leaves.
Students have conducted germination tests on many varieties of seed sent on NASA space shuttle missions. Your students can explore their findings.
Pumpkin seed germination tests will produce a vine of ideas for teaching the growing minds of children.
Sources
- Jakum, Betty. “Testing Seeds for Germination,” The Master Gardeners website
- Nuffield Math Project. Mathematics Begins. New York: John Wiley and Sons, Inc., 1967.
- Washington State University Extension. “Seed Germination” post on website
Arlene Marturano - Arlene Marturano, an educator, consultant, master gardener, and writer advocates gardens as a context and gardening as a tool for ...
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