Re: Can you recommend a fast growing plant for my science experiment?

Dear Reeder:

I think what you're trying to do here is known as a 'bioassay', where the effects of certain substances on a living thing (usually plants) are tested. An example where this can be used is the testing of polluted water, to roughly gauge the toxicity. A good page to check out is: What is a Bioassay?.

As for your question on what plant to use, I would recommend duckweed (of the family Lemnaceae). Although it's winter where you are, I think these plants should still be quite easily obtainable. Duckweed have the fastest growth rate of any flowering plant, and are quite hardy too. There's a really great page on duckweed by someone who loves them even more than I do (= : The Charms of Duckweed.

However, you'll have to do your experiment indoors, preferably under some lamps, because their ideal conditions include warm temperatures from 20-30 degrees Celsius. There's more information on their ideal growth conditions at this place: Growth and Reproduction (of duckweed).

Sometime in the past some of my students tried a similar project using duckweed and it worked out very well, which is why I'm recommending it breathlessly.

However, you still might not be able to get the duckweed, since it's winter. This page Lettuce Seed Bioassays recommends using lettuce seeds, which you can probably get at any gardening store. I haven't tried using them myself, though, so I'm not very clear on how to use them, but the above page has many tips on how to do it. Perhaps you could ask your teacher or parents to take a look and help you with your project.

Remember to include a control sample in your experiment (where the plants are grown in 'normal' water, compared to the other types of water, so you can compare the difference between a healthy plant and one that has been affected by different types of water)!

A book that might be of help is Botany projects for young scientists by Maurice Bleifeld, published in 1992 by F Watts. You could try looking for it in your school library or public library.

It's best if you can get an adult to assist you in your experiment, or to help you get the plants. Good luck with your project! You can email me at pflanzen@smileyface.com if you have any other questions.

Regards,
Thiam Hock