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Weed control using Bay laurel leavesFeatured science projectScience project video


This science fair project was done to study the effectiveness of using natural plant extracts to control the growth of weeds. The science project experiment was performed using different concentrations of juice extracted from Bay laurel leaves.


The higher the concentration of Bay laurel leaf juice, the faster the rate at which weeds are killed.

Scientific Terms

Allelopathy, species, ecosystems, herbicides, germination



Allelopathy describes a condition where a species of plant releases certain chemical substances that are able to inhibit the growth or seed germination of another species of plant. This naturally occurring condition will affect the diversity, structure and growth of the plant ecosystem.

Plants and animals have to compete for space, food and water. In the case of plants, they have to compete for water, nutrients from the soil and sunlight. Plants that are allelopaths have developed chemical means of inhibiting their competitors from growing or preventing their competitors’ seeds from germinating nearby, in order to eliminate competition for resources.

The substances that are released by allelopathic plants are quite similar to herbicides. The source of the allelopathic substance can be the leaves, flowers, tree bark or the roots of the allelopathic plant. Some of the chemicals that are produced by the plants can remain rather persistently in the surrounding soil over a long period of time while others may degrade fairly quickly.

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Complexity level:
Project cost ($):
Time required:
2 hours to prepare, 12 days for science fair project
Material availability:
May be purchased from a plant nursery
Safety concerns:

Handle chemicals with care and dispose of them properly. Wear safety gloves and goggles to prevent injury