Alex's Science Fair Project

"Dandelion Dilemma"

    Pesticides are poisons designed to kill a variety of plants and animals such as insects (insecticides), weeds (herbicides), and moulds or fungus (fungicides). Since the 1960's, use of pesticides has grown. They are used almost everywhere, not only in farmer’s fields. They can be found in the air we breathe, the food we eat, and the water we drink. The dangers of pesticide use, such as development of cancers and childhood leukemia, birth defects, and developmental abnormalities are now becoming well known. Today, more and more communities like Halifax and Ottawa are passing laws which prohibit the non-essential use of pesticides. Homeowners need to find alternatives to pesticides for lawn and garden care.

To see if the use of vinegar is an effective way of controlling weeds (dandelions) without harming the grass.

The 15% acetic acid will kill the dandelions and will not affect the grass.

 containers with dandelions and grass, acetic acid, household vinegar, spray bottle, ruler.

I researched on the Internet the use of pesticides in the environment and alternate ways for homeowners to eal with weeds growing in their garden.

Acetic acid - a clear liquid acid that gives vinegar its characteristic taste.

Pesticides - poisons designed to kill a variety of plants and animals.

1. Fill 5 containers with soil.

2. Plant dandelions and grass seed.

3. Water daily.

4. Wait until grass and dandelions are growing well.

5. Measure height of grass.

6. Obtain 20% acetic acid and household vinegar.

7. Dilute acetic acid to 10%, 15%, and 20%. Handle acetic acid with caution.

8. Mark containers as Control, 5% (vinegar), 10%, 15%, and 20% acetic acid.

9. Spray the containers of dandelions and grass with the appropriate solutions.

10. Measure height of grass in each container and observe and document condition of   grass and dandelions daily.

   The results show that the 5% acetic acid or vinegar was the only solution that provided some weed control without affecting the grass. The other concentrations of acetic acid (10, 15, and 20%) all had some or significant effect on the grass, although they did kill the weeds. The 10% concentration did kill the eeds and did not kill the grass. However, the grass was impacted and showed signs of damage

    This project shows that the 5% acetic acid or vinegar had the least affect on grass, but may not be strong enough to totally kill the dandelion weeds, while the 10% acetic acid killed the weeds but also caused some damage to the grass.

   Chemical pesticides pollute our environment and cause harmful health effects to people. We need to find alternatives that prevent and treat weeds and do not cause pollution.

    Vinegar provides a means of treating weeds such as dandelions and does little harm to the environment. The 10% acetic acid is more effective than vinegar, but has to be used cautiously to prevent damage to the grass. Therefore, the vinegar or the 10% solution may be the best to use in dandelion control, but whatever solution is used, it should be applied directly to the weeds to prevent grass damage. Acetic acid or vinegar s a pesticide would also work best in conjunction with methods to prevent dandelions in the first place.

Project Summary

1. How did I come up with my project idea?

My mom gave me a newspaper article on using vinegar as a weedkiller. I read it and thought it would be a good topic since I don’t like it when our neighbours use pesticides on their lawns.

2. What did I learn from my experiment?

I learned that there are other ways of dealing with weeds like dandelions than using pesticides which may be linked to things such as cancers and birth defects.

3. How close were my hypothesis and conclusion?

I guessed that the 15% acetic acid would kill the dandelions but not hurt the grass. I found that the 15% did kill the dandelions, but that it also affected the grass. The 5% and the 10% acetic acid had less affect on the grass.

4. Did I learn anything new from my project?

Yes. I learned that some communities are now banning the nonessential use of pesticides and that there alternate ways to kill weeds.

5. What was the most interesting part of my project?

It was interesting watching the dandelions die once they were sprayed with vinegar. The ones sprayed with 20% acetic acid died in just over 2 hours.

Alex R

Grade 5

Mr. Murray

St. Bonaventure’s College

St. John’s, NL

 Spraying Weeds

Pesticides