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Project Summary

Difficulty	5
Time required	Very Long (several weeks to months)
Material Availability	Readily available
Cost	Low ($20 - $50)

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Sponsor

Sponsored by a generous grant from Monsanto Fund

Objective

The purpose of this project is to find if the size of the seed determines the ideal planting depth.

Introduction

You may think planting seeds is as simple as putting them in the ground and giving them water. But did you realize that there are a number of different types of seeds that require different conditions to grow? Some seeds may need light to grow, some may need darkness, and some may even need to be charred by fire. So with all these variations in the ideal conditions to stimulate seed germination how does seed size impact the process of germination? Do certain size seeds need special conditions?

Terms, Concepts and Questions to Start Background Research

To understand the relationship between planting depth and seed size, you should have solid understanding of the seed germination process, the structure of a seed, and the factors that break dormancy for different size seeds.

Bibliography

Some sources for information on germination and seed structure:

• http://koning.ecsu.ctstateu.edu/plants_human/seedgerm.html
http://gardening.wsu.edu/library/vege004/vege004.htm
• http://aggie-horticulture.tamu.edu/wildseed/info/3.1.html
• http://www.agron.iastate.edu/plantscience/Planting_depth.htm

Materials and Equipment

• Seeds. We recommend using the following sedds for this project:
  • Garden pea
  • Supersweet corn
  • Onion
  • Lima bean
  • White pinto bean
  • Radish
  • Lettuce
• Scale (for recording weight)
• Ruler (for measuring seed size, plant growth, and planting depth)
• Pots
• Potting soil
• Tape or popsicle sticks to mark each of the pots with the type of plant and planting depth

Experimental Procedure

• Select the types of legume seeds you will be using for the experiment.
• For each seed type, record the weight, size, and recommended planting depth
• For each seed type, determine the planting depths that you will use for this experiment. Here is a recommendation for determining the different depths:
  
  • Depth 1: recommended planting depth
  • Depth 2: surface
  • Depth 3: two times the recommended planting depth (this will be your deepest seed)
  • Depth 4: half way between the surface and the recommended planting depth
  • Depth 5: half way between the recommended planting depth and the deepest seed (which is twice the reommended planting depth)
• For each seed type, plant the seed in a pot at each of the depths. (So if you are using 6 different types of seeds, you will have 30 pots, one for each seed type at each depth)
• You should repeat this experiment at least twice to ensure you get enough data for each seed type at each of the depths.
• After about 17 days, measure and record the heights of each of the plants.

Variations

Is there a relationship between seed size and the amount of light needed to germinate seeds?

• For more science project ideas in this area of science, see Plant Biology Project Ideas.

Last edit date: 2005-08-31 14:56:20