Natural Science Forum / Biology / Botany / December 2004

I posted earlier about a then upcoming episode of the Discovery Channel
TV series, Mythbusters, that did an experiment to determine if music
and talking had an effect on plants. I saw the episode, and it
concluded that is was "plausible" that music and recorded talking
improved plant growth. They got a benefit with both nice and nasty
talking and both classical and heavy metal music. Their control plants
did the worst.

Unfortunately, Mythbusters consulted no trained botanists on camera,
just a garden center employee who thought that supposed benefits of
talking and music on plant growth was an old wive's tale.

Among the problems in the Mythbusters experiment were the following:

1. No statistical analysis.

2. There was only one small greenhouse per treatment so no real
replication to take differing environments into account. A plus was
that there were ten pots with one seed per pot in each greenhouse.

3. One seed per pot was an unwise technique because some of the pots
ended up with no plants due to germination failure. The usual technique
for an experiment of this type would have been to plant three seeds per
pot and then thin to one seedling per pot.

4. Not all greenhouses were oriented in the same direction so light
patterns within the shaded structures could have differed and affected
the results.

5. An LA rooftop in mid-summer provided poor growing conditions for
plants, especially for peas, a cool season crop.

6. The control greenhouse was in the center of the roof. The treatment
greenhouses were closer to the edges. That could have resulted in
significant temperature differences.

7. The automated irrigation system failed midway through the experiment
so plants were harvested early and fresh weights measured. Plants in
some treatments were clearly affected by lack of water more than others
so that skewed the results. It would have been more logical to measure
plant dry weights because about half the leaves on some plants were
dead and dry.

8. There was no attempt to determine a mechanism that would explain why
plants would grow better with sound.

Their experimental errors indicated how easy it is for students to do
experiments on plants and sound incorrectly and reach wrong
conclusions.

The episode was titled "Exploding House."
.

David R. Hershey
dh321@excite.com