1. STC Plant Growth and Development Lesson 4: Thinning and Transplanting (Day 4 or 5) Kennewick School District

2. Overview 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 thin to one plant per section and to transplant the surplus seedlings. 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. This is a hidden slide for teacher information. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

3. Lesson Objectives  Students discuss the purpose of thinning and transplanting.  Students learn how to carry out these two tasks. This is a hidden slide for teacher information. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

4. Background Your students may balk at the idea of thinning. The excitement of planting and of watching the seedlings emerge is still so fresh. Who wants to pull out those tender young plants? But thinning is important. As gardeners thin their beds to give their plants the best possible growing conditions, so must we. For the Brassica plants, it is best to thin to one plant per cell. This ensures that each plant will have ample space, light, food, water, and air circulation. Under these conditions, the plants will thrive and produce the highest possible seed yield at harvesttime. Plants grown under more crowded conditions must compete for these essentials and will be less productive. This is a hidden slide for teacher information. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

5. Background (cont.) There are several ways to thin. One way is to pinch off plants at the soil line. Another way is to cut them off at the soil line with scissors. A gentler way is to pull up the plant, root system and all, and transplant it to another location. In this lesson, students will be given two choices of what to do with the plants they thin: pinching, or cutting off, or transplanting to cells where no seeds germinated. Transplanting takes planning ahead and a gentle touch. Be sure each student has decided where the plant is to go before he or she uproots it. Minimizing time in transit for the plant is important to prevent rood damage. The Brassica is a survivor. Most transplants probably will perk up a few hours after placement in their new cells although they may lag behind developmentally by a few days. This is a hidden slide for teacher information. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

6. Preparation  Set up “class plots” with potting mix, wicks, and fertilizer. Place them in an easily accessible location so students can transplant their plants at their own rate This is a hidden slide for teacher information. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

7. Materials list For each student:  Student notebook  1 toothpick  1 pair of scissors For every 2 students:  1 hand lens  1 pair of forceps (optional) For the class  Potting mix  Surplus planter quads  1 large or several small containers for the class plot (egg cartons, milk cartons cut lengthwise, margarine tubs)  Wicks for above containers (if none available, use cotton twine) STC Plant Growth and Development Lesson 4: Thinning and Transplanting

8. Have you ever had experience thinning or transplanting plants? Why is it important to thin plants? Why is it sometimes necessary to transplant plants? STC Plant Growth and Development Lesson 4: Thinning and Transplanting

9. Observe your plant with a hand lens. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

10. How are the plants different from one another?  Are all the seedlings the same size?  The same color?  Where are the differences, exactly? In the shape or size of the leaf? In the length of the stem?  Did every seed sprout, or germinate? STC Plant Growth and Development Lesson 4: Thinning and Transplanting

11. Decide which one plant from each cell you will keep and which one you will thin out. You will end up with four plants, one per cell. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

12. Thinning and Transplanting STC Plant Growth and Development Lesson 4: Thinning and Transplanting

13. Before thinning…  Gently loosen the soil with a toothpick.  Plan to set aside one of the extra seedlings to draw later. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

14. You may thin your plants by…  Cutting them close to the soil and discarding them. or  Uprooting the plants and transplanting them. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

15. If you choose to uproot your seedlings you have the following choices:  Transplant then into one of their own cells where no seeds germinated.  Donate them to a classmate for transplanting.  Transplant them into the prepared class pots. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

16. Draw and label the parts of one of your uprooted plants in your science notebook. Be sure to include:  The seed leaves, the stem and the roots.  Today’s date and the age of your seedling STC Plant Growth and Development Lesson 4: Thinning and Transplanting

17. seed leaves The first two leaves that appear on a plant after germination. Add this vocabulary word and its meaning to your glossary. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

18. germinate To start to grow from a seed into a new individual. Add this vocabulary word and its meaning to your glossary. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

19. Clean up. Throw away any plants you can’t use and return equipment to their containers. STC Plant Growth and Development Lesson 4: Thinning and Transplanting

20. Discussion  Even though the seedlings are exactly the same age, how were the plants different?  You are all about the same age. How are you different from one another? STC Plant Growth and Development Lesson 4: Thinning and Transplanting

21. Discussion  What are the requirements for plant growth?  What are the optimum conditions for plant growth?  What are the differences between the bean seed embryo and the Brassica seedling? STC Plant Growth and Development Lesson 4: Thinning and Transplanting

22. Update your Table of Contents STC Plant Growth and Development Lesson 4: Thinning and Transplanting