Designing a Plant Science Experiment: Light, Soil, and Fertilizer Variables

Choose Distinct Treatments for Measurable Differences

• Soil: Use pure clay, pure sand, potting soil (your choices too similar).
• Light: Compare 100%, 50%, 10% sunlight (grow light vs. sun too similar unless months-long).
• Fertilizer: 0x, 1x, 10x (0x vs. 1x vs. 4x showed little difference).
• Miracle-Gro vs. no-name: need a year to see difference.

Photos of our setup:

Shade covers demonstrate effect of light levels

Section at right end of bed received no fertilizer

Bed sections filled with (in order) clay, potting soil, sand

Difference between plants grown in clay and in potting soil