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Lesson 2: Chill Out!
To prepare, read Background Information

Objectives
 Students will:

  • Participate in a science experiment to learn the cold requirements of spring-flowering bulbs.

Central Concepts

  • Most spring-flowering bulbs require exposure to cold temperatures in order to bloom.
  • Different varieties of bulbs require different amounts of cold exposure.

Standards addressed: click here

Materials

  • At least five tulip bulbs and five crocus bulbs (preferably 10 of each)
  • Soil
  • Five 6-inch pots and five 4-inch pots
  • Ruler
  • Paper
  • Pencils

Discussion Topics

  • What do bulbs need to bloom? (Most spring-flowering bulbs need exposure to cold temperatures to bloom. All bulbs need access to water to grow and develop.)
  • How can we test a bulb’s need for cold temperatures? (Gather student ideas on experimental design before presenting the activity listed below.)

In-Class Activity
* Note: Some people experience skin irritation from handling bulbs, so make sure students wash hands thoroughly after planting or wear gloves while planting.

1. Using the Background Information, share information about the cold exposure needs of spring blooming bulbs. Tell them you are going to design a scientific experiment to test out this information. They will monitor the growth of each plant in the experiment until it blooms or until growth slows.

2. Fill the 10 pots with soil. In the five 6-inch pots plant tulip bulbs (one or two bulbs for each pot depending on availability – it is best to have two in case a bulb has been damaged). In the five 4-inch pots, plant crocus bulbs (one or two per pot). Click here for information on planting bulbs in containers.

3. Set one pot of tulips and one pot of crocus in the window. Place the other pots in a refrigerator. On a daily basis through the duration of the experiment, monitor the growth and development of the bulbs in the window and record data on a chart (see example chart below).

Plant Name:
Length of Cold Exposure:

Date
Height
Is it blooming?
Day 1  

 
Day 2  

 
Day 3  

 
Day 4  

 
Day 5  

 
Day 6  

 

4. After two weeks, remove a pot each of tulips and crocus from the refrigerator and place them in the same window. Monitor and record the growth data of these as well. Repeat this step at six and eight weeks.

5. Translate your growth charts into graphs and compare the growth of the plants exposed to the various treatments. How long did it take for each plant to bloom? Did all the plants bloom? What does this tell you about the cold treatment needs of crocus versus tulips?

Extensions

Science - In this lesson we tested temperature needs of bulbs. Create additional experiments exploring the effects of other variables, such as light (intensity, quality, and/or duration), water, and fertilizer. Track and measure differences in growth.

Science and Geography - Participate in the Journey North Tulip Project. Journey North is an educational project tracking migrations and seasonal changes based on observational data from classrooms throughout the country.

English - During the above experiment, have students keep a daily journal documenting observations in addition to height data. Encourage them to use these observations in conjunction with the growth charts to arrive at final conclusions.



Copyright© 2005 National Gardening Association

  

September 2005
Kids Garden News

Contents

Newsletter Home

Program Spotlight:
Bulb Award Brings Spring
Color to Vermont School

News Items

Lesson Feature:
Bulbs

Introduction

Background

Lesson 1:
Bulb Botany

Lesson 2:
Chill Out!

Plant of the Month: Tulip

Resources

 

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