Science project

Natural Herbicide vs. Commercial Herbicide

Research Questions:

  • What is allelopathy and juglone?
  • How will the honeysuckle shrub be affected by the application of juglone solution compared to that of a commercial herbicide?
  • How long will it take for a shrub sprayed with juglone solution to die?
  • How long will it take for a shrub sprayed with a commercial herbicide to die?
  • Which plant died first?
  • Based on the experimental results should juglone be considered as a natural herbicide?


  • Honeysuckle shrubs (or seeds)
  • Black walnut hulls (or leaves, bark, or roots)
  • Name brand commercial weed & grass herbicide Ϯ
  • Three plastic cups or flower pots
  • Plant spray bottle
  • Large cooking pot
  • Marking pen
  • Potting soil

Ϯ Purchase only a commercial herbicide designated as being “systemic” if at all possible.

Experimental Procedure:

  1. Gather three young honeysuckle shrub plants and place each in separate flower pots or plastic cups.
  2. Label the three flower pots or plastic cups, “natural herbicide,” “commercial herbicide,” and “control.”
  3. Place all of the plants in an area where they will receive the same amount of sunlight.
  4. Place two or three Black Walnut hulls (or 20 leaves) in a pot and fill the pot half full with distilled water.
  5. Bring the hull-water mixture to a boil. Boil the hulls (or leaves) and water for 10 minutes using the stopwatch to keep track of time.
  6. After 10 minutes, use a large spoon to remove the hulls from the water.
  7. Continue to boil the now extracted juglone solution for 20 minutes.
  8. After 20 minutes, allow the liquid to cool completely. Once the liquid has cooled, pour it into a flower spray bottle.
  9. Follow the directions written on the commercial herbicide label for the amount of herbicide that should be applied to the honeysuckle shrub.
  10. Apply the same amount of juglone solution to the honeysuckle shrub labeled “natural herbicide” as was applied to the “commercial herbicide” plant.
  11. Do not apply any substance to the plant labeled “control.”
  12. Observe the plants over several days recording any changes seen. Write all of the observations in a table.
  13. Use phrases like “no visible change,” “change in leaf color,” “withering of steam,” “stunting of growth,” wilting of plant,” etc. when describing the plants’ appearance over time.
  14. The data in the table can be visually displayed by plotting a bar graph of natural herbicide vs. commercial herbicide eradication time on graph paper or a computer equipped with Excel, by listing the number of days to the shrub’s death along the vertical axis verses the names of the two herbicides along the horizontal axis.

Terms/Concepts: Allelopathy, Juglone, allelopathic effect, autotoxicity, herbicide, walnut toxicity, Black Walnut Tree, juglone toxicity, Honeysuckle shrub; why might it be more desirable to use allelopathic substances as alternatives to the use of traditional commercially produced chemical herbicides?


  • World Food and You, by Nan Unklesbay, pp. 362 (CRC Publishing, 1992).
  • Allelopathy in Sustainable Agriculture and Forestry, by Rensen Zeng, Azim U. Mallik, and Shiming Luo, pp. 305 ( Springer-Verlag New York, LLC, 2008).
Disclaimer and Safety Precautions provides the Science Fair Project Ideas for informational purposes only. does not make any guarantee or representation regarding the Science Fair Project Ideas and is not responsible or liable for any loss or damage, directly or indirectly, caused by your use of such information. By accessing the Science Fair Project Ideas, you waive and renounce any claims against that arise thereof. In addition, your access to's website and Science Fair Project Ideas is covered by's Privacy Policy and site Terms of Use, which include limitations on's liability.

Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

Add to collection

Create new collection

Create new collection

New Collection


New Collection>

0 items