Question
I am an eigth grader doing a science fair project. My topic is "How Much Chlorine Can a Plant Tolerate?" and I would really appreciate some of your help so that i can get some research done. I am testing Lima Beans because they grow faster. I am growing 7 plants 10 times (70 plants total) each in a separate 10cm high cup. I am going to water each cup with a different amount of chlorine. If  you have any comments or suggestions or any possible information, it would be a big help to me.

thank you very much.

Sincerely,

Angela

Answer
Hi Angela,

This sounds like a well-designed science project.

I have a few suggestions. Be sure that all of the plants get the same amount of light and liquid so those factors do not affect the results. In general, provide as much light as possible for the beans and water the soil thoroughly whenever the surface of the soil feels dry.

Chlorine affects some plants more than others, but when the concentration of chlorine gets high enough it will be toxic to just about any plant. I do not know just how much chlorine beans will tolerate, but your experiment should determine what the tolerance level is.

Look for signs of dry, brown leaf edges; wilting; and leaf yellowing as signs of chlorine damage. It may take a week or more for symptoms to show up, especially at lower levels of chlorine concentration.

If you get a chance (I know 8th graders are very busy!), let me know the results.

Let me know if you have further questions.

Regards,
Will Creed
[email protected]