Plant Growth & Development
Lesson 4
Thinning and Transplanting
To maintain a healthy garden, people must periodically thin plants and transplant them to a more desirable location. As part of students’ experience during this unit, they will be asked to thin to one plant per section in their quad and to transplant the surplus seedlings to empty quads. This activity should be done on DAY 4 or 5 after planting. A class discussion about these two practical gardening techniques helps students understand why they are so important.
Objectives:
Students discuss the purpose of thinning and transplanting. Students learn how to carry out these two tasks.
4. Lesson set up and Management
GLE 1.1.4 Understand that energy comes in many forms.
(Lessons 3-7)
*Describe the forms of energy present in a system (e.g., light energy is needed in a plant system so the plant can make food through photosynthesis.)
GLE 1.1.6 Understand the characteristics of living organisms.
(Lessons 1-7, 9, 10, 16)
*Identify observable characteristics of living organisms (e.g., plants have roots, stems, leaves, seeds, flowers; bees have two antennae, compound eyes, six legs, two pairs of wings, a head, thorax, and abdomen).
*Describe how plants and animals get food differently.
GLE 1.2.1 Analyze how the parts of a system go together, and how these parts depend on each other.
(Lessons 1-14, 16)
*Identify the parts of a system (e.g., roots, stems, leaves, flowers, fruits, and seeds) and how the parts go together.
*Describe the function of a part of a system (e.g., leaves are the food factories of Wisconsin Fast Plants.)
*Explain how one part of a system depends upon other parts of the same system.
*Predict and explain how a system would work if one of its parts was missing or broken.
GLE 1.2.2 Understand that energy can be transformed from one object to another and can be transformed from one form of energy to another.
(Lessons3-8, 10-12, 16)
* Identify sources of energy in systems (light energy is the source of energy in a plant system; food energy is the source of energy in an animal system).
GLE 1.2.7 Understand the life cycles of plants and animals, and the differences between inherited and acquired characteristics.
(Lessons 3-12, 16)
*Observe and describe the life cycle of a plant or animal (e.g., Wisconsin Fast Plant).
*Describe that the young of plants and animals grow to resemble their parents as they mature into adults (e.g., Wisconsin Fast Plants; bees).
*Describe inherited characteristics (e.g., leaf shape, flower shape and color).
GLE 1.3.8 Understand that living things need constant energy and matter.
(Lessons 3-12, 16 and EXTENSIONS: students also earn information from listed books, videos, web sites)
*Identify sources of energy and matter used by plants and animals to grow and sustain life (e.g., air, water, light, food, mineral nutrients).
*Identify sources of energy and matter used by animals to grow and sustain life (e.g., air, water, light, food, mineral nutrients).
*Explain how plants and animals obtain food (e.g., plants make food from air, water and sunlight, mineral nutrients; animals obtain food from other living things.)
GLE 2.1.1 Understand how to ask a question about objects, organisms, and events in the environment.
(Lessons 1-16)
*Ask questions about objects, organisms, and events based on observations of the natural world.
GLE 2.1.2 Understand how to plan and conduct simple investigations following all safety rules.
(Lessons 1-16)
*Make predictions of the results of an investigation (e.g., growth rate of the Wisconsin Fast Plant during the growth spurt).
*Generate a logical plan for, and conduct, a simple controlled investigation with the following attributes: 1) appropriate materials, tools, and available computer technology, 2) gather, record, and organize data using appropriate units, charts, and/or graphs
*Identify and use simple equipment and tools (such as magnifiers, rulers) to gather data and extend the senses.
*Follow all safety rules during investigations.
GLE 2.1.5 Understand how to report investigations and explanations of objects, events, systems, and processes.
(Lessons 1-16)
*Report observations or data of simple investigations without making inferences.
*Summarize an investigation by describing: -materials used in the investigation, -observations, data, results, -explanations and conclusions in written, mathematical, oral, and information technology presentation formats, -safety procedures used
GLE 2.2.1 Understand that all scientific observations are reported accurately and honestly even when the observations contradict expectations.
(Lessons 1-12, 15, 16)
*Explain why scientific observations are recorded accurately and honestly.
*Explain why scientific records of observations are not changed even when the records do not match initial expectations.
*Explain why honest acknowledgement of the contributions of others and information sources are necessary.
GLE 2.2.3 Understand why similar investigations may not produce similar results.
(Lessons 3-12, 15, 16)
*Describe reasons why two similar investigations can produce different results (e.g., identify possible sources of error, different rates of plant growth).
GLE 2.2.4 Understand how to make the results of scientific investigations reliable.
(Lessons 3-12, 15, 16)
*Describe how the method of investigation insures reliable results (i.e., reliability means that repeating an investigation gives similar results).
GLE 2.2.5 Understand that scientific comprehension of systems increases through inquiry.
(Lessons 3-12, 15, 16)
* Describe how scientific inquiry results in facts, unexpected findings, ideas, evidence, and explanations.
GLE 3.2.2 Understand that people have invented tools for everyday life and for scientific investigations.
(Lessons 1-12, 15, 16)
*Describe tools (technology) invented to advance scientific investigations (e.g., rulers, plant lights, automatic watering system, magnification devices, the development of Wisconsin Fast Plants by Dr. Paul Williams for classroom investigations).
- Many plants follow a life cycle that begins with growth from a seed and proceeds through the production of many new seeds.
- Plants have different stages in their life cycle.
- To live and grow, plants need light, water, carbon dioxide from the air, and mineral nutrients from the soil.
Thinning to one plant per quad section will ensure that each plant will grow in an optimal environment – ample space, light, food, water, and air circulation. Crowded conditions mean that each plant must compete for these essentials. Crowded plants will not grow as well and will not produce as many seeds.
Transplanting takes planning and a gentle touch. A quick transfer from one location to another will prevent root damage. Most transplants will perk up within a few hours, but may lag behind in growth by a few days.
Thinning techniques:
- Pinch off plants at the soil line.
- Cut plants off at the soil line with scissors, being very careful to only cut one plant!
- Gently pull up the plant, roots and all.
Transplanting technique:
- Prepare a quad by inserting a wick, filling it half way with moist soil, and adding 3 fertilizer pellets. Use a toothpick to loosen the soil around one seedling from the quad being thinned. Gently transfer the seedling to the prepared empty quad, being very careful not to crush the stem or destroy the root. Fill to the top with moist soil. Keep the soil moist by watering from the top with a dropper for a few days until the wicking system begins to work.
4. Lesson set up and Management
Because this is a long lesson, you might want to spread it out over two days. Students can prepare the planters on the first day (Steps 1 through 5 on Activity Sheet 2) and complete planting the seeds on the next day (Steps 6 through 11 on Activity Sheet 2)
Materials:
Every student will need:
- Student notebook
- Toothpick
- Pair of scissors (only if thinning and not transplanting)
Every pair of students will need:
- Hand lens
- Forceps (optional)
Tip:
Students tend to crush the stem of their plant when using forceps because it is very easy for them to squeeze too hard. A crushed stem will result in a dead plant. Students tend to have greater control and a more gentle touch when using their fingers for transplanting. Use forceps only if thinning and not transplanting.
The class will need:
- potting mix
- empty planter quads with wicks in place
- fertilizer pellets
PREPARATION (~ 10 minutes)
If your class is thinning only, then you will not need to prepare for transplants. If transplanting, set up the quads that will receive the extra plants. Cotton twine may be used in place of wicks if you don’t have enough wicks left. Set up the quads so that students can easily transplant their plants. Students have the following options:
- Transplant extra seedlings into one of their own quad cells where no seeds germinated.
- Donate extra seedlings to classmates who have empty quad cells.
- Transplant extra seedlings to prepared class quads.
Student Management:
PROCEDURE
Students will be either thinning only or thinning and transplanting. They will end up with a total of 4 plants in each quad. After students have removed a plant from the soil have them draw and label the uprooted seedling in their student notebooks. This is the only opportunity students will have to view the roots. Student drawings should include cotyledon leaves (seed leaves), the stem and roots. Remind students to include today’s date and the age - in days - of the seedling with their observations.
Tip:
If your class has read the first book in the Boxcar Children series, make a point to discuss the section where the older boy is thinning the garden for the doctor and link it back to this lesson.
FINAL ACTIVITIES
Class discussion topics:
- Discuss individual differences in seedlings that are the same age.
- Review the requirements for plant growth.
- Review the optimum conditions for plant growth.
- Review the parts of the plant and how the parts work together in the plant system.
- Discuss the differences between the bean seed embryo and the Brassica seedling.
EXTENSIONS
Set the extra class plants aside. When the flowers open and it is time for cross pollination, do not cross pollinate these plants. Students will see that the flower petals will fall off just like the cross pollinated plants, but the seed pod will not grow.
ASSESSMENT
Check the overall quality of notebook entries. The seedling drawing should be complete, clear, and accurate. The cotyledon leaves should be somewhat heart-shaped and labeled correctly (they are not true leaves). Share exemplary student work with the class.
Writing Support:
- Have students draw and label an uprooted seedling in their science notebooks. Student drawings should include cotyledon leaves (seed leaves), the stem and roots. Remind students to include today’s date and the age - in days - of the seedling with their labeled drawing.
Reading Support: Students use non-fiction reading skills.
- ScienceSaurus, A Student Handbook (use as a resource)
- How a Plant Grows
Have students partner-read and write interesting facts and questions they may have on sticky notes. Students leave their sticky notes on the pages of the book until they are ready to transfer their sticky notes into their student notebooks. Students will read this book cover to cover over the course of this science unit.