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Lesson 2: Classroom Cuttings

To prepare, read Background Information

Objectives
 Students will:

  • Learn about vegetative (asexual), propagation of plants
  • Observe the growth of roots on cuttings
  • Compare different rooting media for cuttings

Standards addressed: click here

Materials:

  • Stock plants such as coleus (Coleus spp.), Swedish ivy (Plectranthus australis), or wandering jew (Tradescantia zebrina). You'll need enough so that each student can make two cuttings.
  • Clean scissors
  • Clean plastic water bottles with the tops cut off
    (Note: Cutting plastic can be tricky and should be done by adults ahead of time.)
  • Water
  • Moistened soilless potting mix
  • Dark colored construction paper (optional)

Central Concepts:

  • Plant growth and development
  • Factors affecting rooting

Discussion Questions

1. What happens if you cut off a person’s toe? Will it grow back? Will it grow into a new person?

2. What happens if you cut off a stem from a plant? Will it grow back? What will happen to the cutting?

In-Class Activity: Comparing Rooting in Different Media

1. Explain to students the concept of vegetative propagation and how to take a cutting.

2. Give each student 2 plastic bottles with the tops removed. Instruct students to fill one of their bottles with water (call it “the vase”). Fill the second with moistened soilless mix (call it “the pot”).

3. Show students how to take stem cuttings from the stock plant and then let them each take two cuttings. Use clean scissors and make sure that each cutting measures 4 to 6 inches long and has at least 4 leaves. (For fair comparisons, each student should use two cuttings from the same stock plant.) Have students remove the bottom leaves so that you can see the stem. Next, have them place one cutting in the vase and one in the pot.

Note: The point at which the leaves attach to the stem is called the node. For many plants, the node is where roots will first emerge, so make sure at least one node is below the water or soil surface.

4. In the vase, only the stem should be submerged in the water. Students may need to adjust the water level to make leaves are above the surface. In the pot, students should insert the cutting against the side of the pot so they can easily observe root growth.

5. Monitor the plants daily and check for root growth, and record any changes. Compare root growth in the vase versus the pot. Have students add more water to their vases if it dips below the original level. They should also make sure the soilless mix in the pots remains moist.

6. Finally, kids can pot up their cuttings to keep in the classroom, take home, or give to family and friends.

Students can also test the effect of light on root growth. Divide the class in half. One team can cover their pots with removable, dark-colored construction paper sleeves while the other team covers their vases. Does light affect root growth?

Extensions:
Science: Take a field trip to visit a local nursery to see propagation practices and equipment in person. If a field trip is not feasible, contact the nursery to see if a speaker can come to visit the classroom for a hands-on demonstration.

Math -- Keep track of the development of root growth in pots versus vases. Students can use statistics or create graphs to document and compare various data:

  • Number of days between making cuttings and when roots first appear
  • Root data – After 2 to 3 weeks of growth, they can remove the plants from the soil and the water and use other measurements to compare root growth using the two methods
      a. count and compare the number of roots on each cutting
      b. measure the roots of plants on the two cuttings

Wrap up the activity by giving students time to prepare a summary of their findings including discussion of their conclusions.

English -- To reinforce the process of taking a cutting and to practice communication skills, ask students to write instructions for making cuttings. The instructions could be written in paragraph form or as an itemized list, and can include illustrations.

History, Social Sciences or Geography -- Explorers and plant collectors of the past and present use the technique of taking cuttings to document and move plants around the world. Lead students in brainstorming session about why cuttings are useful tools for plant transportation. For background, see The Plant Hunters.

Also challenge them to consider some of the dangers of introducing plants into new environments. Use examples of invasive exotic plants in your area (e.g., kudzu, eucalyptus trees, purple loosestrife).

 

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