Water the Plants! Add Sugar? Would Adding Sugar to the Water Increase the Growth of Plants?

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Updated on Jun 25, 2014

Grade Level: 6th - 8th; Type: Biology


To determine if adding sugar to the water would increase the growth of plants?

Questions for Background Research:

  • What gives green plants their green color?
  • How do green plants obtain their food?
  • What is photosynthesis?
  • What is chlorophyll?
  • Are all sugars the same?
  • How do plants store sugar?
  • What are some of the methods being used to increase plant growth?
  • What is a control in an experiment?
  • Of what value is a control in this experiment?

On the information level, this experiment serves to acquaint students with basic information on the basic processes of the growth of green plants. Plants produce their own food by the process known as photosynthesis. The word photo synthesis when broken down into its component syllables yields photo meaning light and synthesis meaning putting together and thereby informs us that plants require light in order to produce their own food. Plants trap the sunlight and produce carbohydrates (sugars and starches) which in turn are converted into energy. It would seem logical to assume that were we to add sugar such as glucose to the water which plants require , we would increase the growth of the plant . Logical, yes? Will it work? Let us find out!

This science fair experiment also serves to acquaint 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 or graphic presentation of data and of being able to make better judgments as to the validity and reliability of their findings. They take on the role of scientists and in the process they learn to act as one.


  • six geranium plants of approximately the same size
  • sugar
  • water
  • a beaker
  • a graduated cylinder
  • a table spoon
  • a metric ruler
  • paper towels
  • a camera (if you wish to take photos of the procedure and the results).
  • These are all readily available from the local gardener, Home Depot or Wal-Mart’s.

Experimental Procedure

  1. Gather all the materials you will need for this project. These include six geranium plants of approximately the same size, sugar, water, a beaker, a graduated cylinder, a tablespoon , a pen, labels, tape, paper towels and a camera (if you wish to take photos of the procedure and of the results).
  2. Copy the charts provided on the next page so that you can record the data on a daily basis and summarize your findings at the close of this project.
  3. Divide the geranium plants into 2 groups, one will serve as the experimental group and the other will serve as a control group. Label the plants in each group .The experimental group may be #1EXP, #2EXP and #3EXP, the control group may be #1CON, #2CON, and #3CON.
  4. Find a location where all of the plants can receive an equal exposure the sunlight. Place the plants there for the duration of the project, the next 14 days. You may wish to start taking photos now.
  5. Make up a sugar solution using four tablespoons of granulated sugar to every 32 ounces of water. In watering the plants you will give each plant the same amount of water. You can make the sugar solutions as you need them each day for 14 days. The control group will receive only water; however it will be the same amount of water as the experimental group.
  6. Observe all the plants and in your data chart record the height of each plant, the number of leaves and any additional observations that you think are worth noting. Continue this procedure for 14 days.
  7. Review all the recorded data and the photos you have taken. What are your conclusions? Write up your report. Make certain to include all of your research, your charts and your bibliography.
  8. Has this project given you any new ideas about further project for the coming year? If so, start planning now. Good Luck!

The Daily Chart of Observations

Plants Height of Plants Number of Leaves Other

Plants Average Height Average # of Leaves Other Data
Experimental Group
Control Group

Terms/Concepts: Green plants, photosynthesis, glucose, carbohydrates, starches, energy, hormones, plant respiration.


Towle, A. Modern Biology, Harcourt, Brace, Jovanovich 1991

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 âNow That I`m Dead, I Decided to Write this Bookâ.

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