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The Best Choice for Growing Large, Flowering Plants

3.3 based on 3 ratings

Updated on Aug 07, 2013

Which of the following will grow larger plants with a greater number of flowers in the same time period, under the same conditions of water, light and temperature? Those in compost, those in soil plus miracle- gro or those containing a mixture of both?




Middle School

Difficulty of Project



$ 10- $20

Safety Issues

Wear safety glasses and plastic or garden gloves when handling the different soil samples.

Material Availability

If you wish, create your own compost. See reference to Composting 01 below. If not , purchase it with all the other materials from a local garden center.

Approximate Time Required to Complete the Project

Five to six weeks. This is a function of the kind of plants you select and includes collection, recording and analysis of data, summary of results and completion of your report and bibliography.


To design and conduct an experiment to determine which of the following will grow larger plants with a greater number of flowers in the same time period, under the same conditions of water, light and temperature, those in (a) compost, (b) those in soil plus Miracle -Gro or(c) those containing a mixture of both?

Materials and Equipment Required

  • compost soil
  • regular soil
  • pkg. of Scott`s Miracle- Gro soil mixture
  • soil from your backyard (as a control)
  • seeds of a flowering plant
  • 5 pots of same size
  • trowel
  • light source for plants
  • air thermometer
  • measuring cup
  • water
  • charts for data collection
  • graph paper for display of results
  • Optional: Camera for photos of plant specimens at different stages of growth and or p photos of the steps taken in conducting the experiment. These photos may be part of your display and add points for dramatic value.


Background Information:
  1. Visit Composting 101 on the internet. You will learn how to create a quick and easy compost soil. Knowing what compost contains will assist you in formulating your hypothesis.
  2. Investigate the claims made by gardeners as to the value of using compost. Will their claims influence your hypothesis?
  3. Investigate the claims made by Scotts who produce Miracle –Gro . Will their claims influence your hypothesis?
  4. This science fair experiment also serves to acquaint you, the students, with the essential processes of sciencing such as the importance of the use of a control, of identifying dependent and independent variables, of data collection, of pictorial and graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. You take on the role of scientists and in the process you learn to act as one.
  5. In your report, make certain to state your hypothesis and the rationale for your prediction, identify the variables, describe the role of the control and state your results.

Research Questions:

  • Visit Composting 101 on the internet. You will learn how to create a quick and easy compost soil.
  • Investigate the rationale for keeping the atmospheric conditions of light and temperature the same for all plants.

Terms, Concepts and Questions to Start Background Research

  • What is a control? A control is the variable that is not changed in the experiment.
  • What purpose does a control serve? It is used to make comparisons as to what changed or possibly caused the change.
  • What are variables? Variables are factors that can be changed in an experiment.
  • What is an independent variable? The independent variable is the one that is changed in the experiment.
  • What is a dependent variable? The dependent variable is the one that changes as a result of the change in the independent variable.
  • What is the hypothesis? It is the prediction you make as to the results of the experiment, what you think might be the result or results.

Charting and Graphing Data

In the experiment, use charts to display the obtained data such as the following sample:

Type of Soil



Size & or Number of Flowers


Soil Plus Miracle-Gro

Mix of Compost & Soil Plus Miracle-Gro

Yard Soil Control

Experimental Procedure

  1. State the problem you are going to investigate in this science fair project.
  2. Create the data sheets you will use to record your observations.
  3. Gather all your materials.
  4. Put on your safety glasses and apron.
  5. Purchase 10 lbs of compost or prepare compost, following quick and easy recipe on Compost 101 in internet.
  6. Fill each of 4 pots and label, #1 with compost, #2 with soil plus Miracle-Gro, and #3 with 50/50 compost and soil with Miracle-Gro, #4ordinary soil from your backyard, serving as the control.
  7. Plant the same number of seeds in each pot following the directions on the seed packet.
  8. Make certain that all plants are exposed to the same conditions of light and room temperature during the entire month.
  9. Measure the growth of each plant noting height in centimeters and the size and or number of flowers for the month.
  10. Optional: You may want to take photos to document your observations.
  11. Optional but worthwhile: You may want to graph the data.
  12. Prepare your final report. Make sure that you include all of the following: a clear statement of the problem, your hypothesis, a list the materials used. Include the safety precautions taken. Describe the procedures used. Include all the data that were gathered. Include all charts and graphs. Formulate your conclusions. For dramatic value, you may include photos of the materials used or of you in the process of conducting this investigation. Include a bibliography of sources you used. As a final statement, you may wish to assess what you did and describe what you would do differently if you were to do this project again.


  • List all the sources of your information, books, magazines, articles, internet resources and individuals. Include
  • A final note: Good Luck!

Dr. Muriel Gerhard (Ed.D.) is a retired educator with fifty seven years of experience in all aspects of public education. She has been a teacher, principal, administrator, college professor, researcher, grants writer, change agent and science editor. She is the author of several books on education used as college texts. These include the best selling Effective Teaching Strategies with the Behavioral Outcomes Approach and The Behavioral Outcomes Handbook for Teachers and Administrators. Presently she is a consultant in science education and curriculum development, a marriage and family therapist, a newspaper columnist and an author. Her latest book, recently published, is a memoir of sixty vignettes entitled Ć¢Now That I`m Dead, I Decided to Write this Book."