Reaping What We Sow

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Updated on Feb 08, 2012

Grade Level: 6th - 8th; Type: Agricultural Science


This project involves a study of the relationship between seed size and plant size. The goal of this project is to determine whether or not bigger seeds yield bigger plants.

Research Questions:

  • What is the relationship between seed size and plant growth?
  • How can the answer to the above question be used to improve agricultural techniques?


  • Computer with Internet access
  • Color printer
  • Digital camera
  • Typical office/hobby/hardware/craft supplies (paper, poster board, glue, etc.)
  • One giant, ripe sunflower
  • Soil
  • Popsicle sticks
  • 30 feet of outdoor fencing at least six feet high.
  • Twine
  • Tape measure All materials can be found in your home, at local stores, or on ebay. Introduction: The question has often been posed, “Do bigger seeds yield bigger plants?” An online search reveals assorted yes-or-no answers to this question. This simple experiment involving sunflowers will shed further light on the subject.

Experimental Procedure:

  1. Read overview of relevant topics (see bibliography below and terms listed above)
  2. Address all of the above terms and research questions.
  3. Search and print out interesting images of different types of sunflowers, or any other types of plants you choose to include in this experiment.
  4. Take photographs throughout the course of the experiment.
  5. Remove the seeds from one large ripe sunflower.
  6. Remove the seed hulls
  7. Separate the seeds into two groups – smallest and largest. Both groups should contain the same number of seeds.
  8. Weigh each seed group precisely and record these measurements.
  9. Plant each of the seeds about six inches from the fencing, about 12 inches apart.. When the sunflowers reach 10 inches in height, use twine to tie them loosely to the fence.
  10. Carefully mark each one small or large. Use the popsicle sticks as ground markers.
  11. Water the plants until fully grown. Sunflowers are ripe when the seeds turn black.
  12. Measure the height of each sunflower, and calculate the average height for each group.
  13. Cut off the heads and weigh both groups of sunflowers. Compare these measurements.
  14. Remove the seeds from each group of sunflowers, and count how many seeds are in each group. Then, weigh each group.
  15. Carefully record all observations.
  16. Analyze your data.
  17. Interpret your findings in a detailed report.
  18. Include interesting photos, diagrams and live sunflowers in your science fair display. Maybe even include a few sunflower recipes.

Terms/Concepts: Germination


Judee Shipman is a Bay Area Educational Consultant and professional writer of quality educational materials. Her recent writing credits include (a popular and entertaining website about states), and a book called The Portable Chess Coach (Cardoza, 2006), currently available in stores.

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