[Jesse]

Jesse  asked the Naked Scientists:
   
Dear Naked Scientists,

I love your show, and listen to it every week.

Here is a question: I've heard that talking positively to plants makes them grow better. Is there any good scientific evidence for or against that claim?

Thanks,
Jesse
Ithaca, NY, USA

What do you think?

[Make it Lady]

Breathing CO2 on a plant may have a small, small difference but what really happens is that people talking to their plants give them more care and attention generally.

[Don_1]

I suspect MIL is about right.

I should think the only way to put it to the test, would be to treat 3 identical plants the same. Talk to one, shout and scream at another and ignore the last.

I would think after a week or two you will get a result, that being, a visit from the men in white coats.

[chris]

Scientists have discovered some sound-sensitive genes in plants that, they suggest, can modulate gene expression in response to the presence of certain audio frequencies; suggests that wheat really does have "ears"!

Actually I'm a little sceptical and I've not seen any follow up of the observation, so it might be just "noise" in the research field. (Sorry, terrible puns).

http://www.thenakedscientists.com/HTML/content/news/news/833/

Chris

[Laura_Kelly]

From an episode of mythbusters a while back, they played different types of music to plants. Their control tests grew at a normal rate, and those with additional noise grew faster. From memory, rock music was the most successful; I'm assuming this is because of an increase in the noise. Classical was the least successful of all the music.

[thedoc]

Listen to the answer to this question on our podcast.

[Lily]

Actually, I stumbled upon this while trying to find sources for a lab report I'm writing. I just finished conducting an experiment like the one mentioned above. I bought 3 identical plant (well...as near as I could come to identical)and yelled and screamed at one, sang and spoke nicely to the other and ignored (aside from watering) the other. They all stayed in the same place except when they were getting their 'treatment' so that no other factor could come into play. Although I did feel crazy, the one that got yelled at kept wilting afterwards, even though it grew at a similar rate. All in all, the one we sang to did only slightly better. The one that grew the least was the one that got ignored...weird.

[ewasankari]

I just helped my daughter conduct this test to see if positive language vs. negative language had an effect on plant growth for a school science project.  We grew 3 pots of snap beans (2 beans per pot) in equal soil levels, receiving equal sunlight (all next to each other on the same window sill) and receiving equal water (3 tbsp / day).  The plants sprouted from the soil on day 6 and the testing began.  One plant was used as a control (not spoken to) one was spoken to with sweet, positive language, and the third was screamed at with harsh language, each test plant receiving 5 minutes of conversation per day at night, when removing them from the window sill would not be robbing them from sunlight. 
The results were amazing.  The plant spoken to with encouraging words was 5 cm taller than the others after 5 weeks and far more robust with incredibly larger leaves and a lot more branches.  The ignored plant (control) was in the middle for growth and was healthy looking.  The plant subjected to the negative language was the shortest  and it's stock was rather irregular shaped with some branches growing downward.   On a few occasions during the testing period it was observed after some particularly loud and intense screaming sessions that the leaves actually began to wilt - no joke.

One common theory of talking to plants = growth stimulation is caused by the Co2 release from our speech infusing the plants with with the needed Co2 but yelling produces Co2 and the plants were only subjected to 5 minutes of speech/day, probably not enough exposure to have an effect.  Admittedly, our sample size was small, but the results were interesting.  Makes me think more about the power of words...........   

[Don_1]

ewasankari,

First off, welcome to the forum.

Though your experiment may appear to have given results which seem to confirm that talking to plants can be of benefit, you really did not have a big enough sample to come to any definitive conclusion. The fact is that two or more plants can show differing growth patterns even though they have been subjected to identical conditions.

As a case in point, I took 3 cuttings from a Hibiscus last autumn. All three cuttings were the same size and from the same plant. All were planted in identical pots with the same compost and kept in identical conditions. I have just had a look at the cuttings and can report 2 are doing fine with healthy signs of budding, but the third is not doing so well. Though it has survived it shows little sign of budding.

BTW, I have not conversed with any of them.

I don't want to put a dampener on you, but it might well have been that your plants would have shown the same results whatever treatment they were subjected to.

All the same, well done. Perhaps you might like to try again, one day, with a bigger sample and subjecting the plants to both speech and recorded sound. But to come to any meaningful conclusion, your sample will need to be of at least 10 plants per set condition and even then the result could only be considered as suggestive, not confirmed.

As the podcast has suggested, CO₂ is probably the greater factor, but vibration may also play a part, artificially tricking the plant into strengthening to be more resilient against wind.