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Q:
Does the type of light effect the growth rate of a tomato?
- Johnathon Currid (age 15)
MCW, Welcome, Minnesota, USA
A:
Johnathon -
The most important thing for how the plant will grow is
how much
light it gets. Plants use special molecules called chlorophyll to turn
light energy into chemical energy that they can use. The more of this
energy that the plant gets, the more it will grow. So, if you use a
really bright light, you will probably find that your plants will grow
more than if you use a dim one.
But there's more to it than just this. The chlorophyll that the
plant uses to get energy is green (hence the fact that most plants are
green). When something looks like it is a certain color, it's actually
because all the light of that color that hits it bounces right back
off. The white light from the sun is actually a mixture of all the
different colors of light (this is why separating the colors gives you
a rainbow). When the white light hits the leaves of the plant, the
chlorophyll absorbs all the colors except for green and the green
bounces right off. So I'd bet that if you tried this experiment at
home, you might find that the plant doesn't grow very well under a
green light, but that it does fine with blue or yellow. Since I'm not
sure about this, please try it and let me know what happens.
-Tamara
(published on 10/22/2007)
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