Does the color of light affect plant growth?

Question

I have a science project and need to find out if the color of light affects plant growth, and if so, what color affects it most, or what color plants grow best in. Any information is appreciated. Thank you so much!

Answer 1

Light quality refers to the color (wavelength) of light. Sunlight supplies the complete range of wavelengths and can be broken up by a prism into bands of red, orange, yellow, green, blue, indigo, and violet.

Blue and red light, which plants absorb, have the greatest effect on plant growth. Blue light is responsible primarily for vegetative (leaf) growth. Red light, when combined with blue light, encourages flowering. Plants look green to us because they reflect, rather than absorb, green light.

Knowing which light source to use is important for manipulating plant growth. For example, fluorescent (cool white) light is high in the blue wavelength. It encourages leafy growth and is excellent for starting seedlings. Incandescent light is high in the red or orange range, but generally produces too much heat to be a valuable light source for plants. Fluorescent grow-lights attempt to imitate sunlight with a mixture of red and blue wavelengths, but they are costly and generally no better than regular fluorescent lights.
Try this experiment
Objectives/Goals
My objective is to find out how different light colors affect plant growth.
Methods/Materials
- 4 boxes
- Colored Transparencies: Red, Blue, Green, Yellow, and Clear.
- 5 flower pots and plastic bowls (for drainage)
- 15 lima bean seeds
- Potting soil
- Tap water
- 5 rulers
- Scissors
- Box cutters
- Construction paper in Red, Blue, Green, Yellow, and White.
- Tape
- Cup
- Paper towel
I built three boxes with 5 different colored transparencies on top and front. I planted seeds about ½ inch
into the pots and let them grow. I recorded measurements every 2-3 days. The Plants were shown different
colored light. There were 3 different plants for each different colored light. I measured overall height and
leaf width for the tallest and best plant of each color.
Results
The red grew the tallest, but the transparent was the healthiest. The blue died midway through the project
and the yellow was close to beating red. The green did poorly.
Conclusions/Discussion
My hypothesis was somewhat correct because red was the tallest and green was the worst living plant. I
did not expect that the transparent plant would be the healthiest. I conclude that if you want a healthy
plant show the plants the full color spectrum, but if you want a tall plant you should only show the plant
red light.
Hence it can be said that
Yes, light color definitely affects plant growth. Natural sunlight contains the full visible spectrum, plus plenty of non-visible spectrum. When a plant is deprived of the spectrum of light on which it depends, it will suffer. The "Grow-Lights" available for plants are expensive because they have made sure to include all the important spectrum elements necessary for a healthy plant's growth.

Since Science Fair is probably coming up at your school, an interesting experiment would be taking one kind of plant, putting different specimens into different pots, and testing growth rate and health under exposure to different colors of light. This way, you can see for yourself, and wind up with a possible winning project.

Answer 2

Light is needed for the plant for photosynthesis. The light of the sun is white or a pale color and it is the best for plant growth. I recently did an experiment to see how different color of light affect the rate of plant growth. I used a red light bulb at 60watts, an ordinary pale white color light bulb, a Green colored light bulb and a blue colored light bulb, all with 60watts. I discovered that the plant with the pale white color light shining upon it, photosynthesised faster, than the others. I got an A for it too.

Hope this helps

Answer 3

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RE:
Does the color of light affect plant growth?
I have a science project and need to find out if the color of light affects plant growth, and if so, what color affects it most, or what color plants grow best in. Any information is appreciated. Thank you so much!

Answer 4

Yes, light color definitely affects plant growth. Natural sunlight contains the full visible spectrum, plus plenty of non-visible spectrum. When a plant is deprived of the spectrum of light on which it depends, it will suffer. The "Grow-Lights" available for plants are expensive because they have made sure to include all the important spectrum elements necessary for a healthy plant's growth.

Since Science Fair is probably coming up at your school, an interesting experiment would be taking one kind of plant, putting different specimens into different pots, and testing growth rate and health under exposure to different colors of light. This way, you can see for yourself, and wind up with a possible winning project.

Answer 5

Plants absorb blue and red light and use this to drive photosynthesis, which in turn gives the necessary compounds required for growth (Simply put). They are green because they reflect those wavelengths. Because plants absorb red light, they can use the ratio of red light to near infrared (NIR) light to determine if they are being shaded by another plant above. This is done using the phytochrome system. For example if an understory plant is being shaded out by the canopy above the amount of red light coming into the understory will be low in comparison to the NIR. Through the use of the phytochrome system the plant responds by longer shoot elongation. If the opposite is the case and there is lots of red light to NIR then the plant will respond by deploying more leaves. Phytochrome sensing of R:NIR is also important in flowering and seed germination. Blue light is usually concerned with plant hormones that regulate stomata openings (Hey the light is on and its time to do some photosynthesis, which requires CO2) and phototropism (plants bending to or away from light). For a plant to grow successfully it requires both red and blue light. Using one or the other will not allow the plant to grow to its fullest and result in odd structured plants

Answer 6

Yes, it does. The chlorophyll contained in the chloroplasts of plant cells absorb light at two wavelength regions, in fact in terrestrial plants there are two types of chlorophyll namely a and b. They both have a bimodal absorption spectra (see reference below) where they absorb light strongly, but they also have a region of wavelengths where they are inefficient at the process. So, the color of light within the photosynthetically active radiation region (visible light that supports photosynthesis) is very important and has a direct impact upon plant photosynthesis and therefore growth.

Answer 7

Yes, because the chlorophyll in the plant only absorbs light at certain wavelengths. My recollection of what happens when you restrict a plants exposure to only one color of light is that red works best, and green the worst.

Answer 8

what about using the green tinted light (like a party light) to work in the grow area at night? is it true that this will not affect the plant photo period?

Answer 9

In the superstore, fruits are usually selected far too soon. Some are rocks, many are bad. Some of the fruit and vegetables are generally right (zucchini, onions, garlic, lettuce, greens, and a few others) so I'd have to go with vegetables.