En Español

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
685 ratings

Friday - March 13, 2009

From: Austin, TX
Region: Southwest
Topic: General Botany, Container Gardens
Title: Do plants grow faster in natural or artificial light?
Answered by: Nan Hampton

QUESTION:

Do you think plants will grow faster in natural light or artificial light or a combination of both? And why do you think that. and need your answer for my biology project please and thank you for your time

ANSWER:

First, I think you need to define what you mean by "faster".  For instance, plants growing in very low light tend to become very tall, but it isn't because they are increasing their cell number.  Instead, their cells are elongating without dividing in an attempt to find light to carry out photosynthesis.  Photosynthesis is how plants convert the energy of the sun into food for growth.  See the answer to a previous question: "Why do plants grow faster in the dark?" So, it seems to me you need to decide for your experiment what measure you will use to determine growth.  Will you use plant height, number of leaves, size of the leaves?

Visible light is one of the forms of electromagnetic radiation that we receive from the sun.  We measure electromagnetic radiation in 'wavelengths' and the units we use are nanometers (nm). A nanometer is very small—one billionth of a meter, or one millionth of a millimeter.  We see the different wavelengths in visible light as colors. For instance, the wavelenths around 475 nm gives us blue light, those around 510 nm gives us green, and near 650 nm is red.  Plants don't use the entire spectrum of light for photosynthesis, they absorb light at two wavelengths to use in photosynthesis—430 nm, at the blue/violet end of visible light, and 662 nm at the far end of red.  You can read about the light spectrum and photosynthesis.   Natural light from the sun, of course, contains these wavelengths, so you expect—all other factors being equal—that plants would grow very efficiently in natural light. 

Synthetic light does not necessarily carry all wavelengths of light, different synthetic light sources produce different spectra.  You can see graphs of spectra from different light sources in a paper about how light wavelength and intensity affect poultry performance. However, there are lights made especially to produce light at the wavelengths that are used for photosynthesis.  You can find thousands of entries about such lights by googling "plant grow lights."  These "grow lights" should also be very effective in making plants grow.  There is, however, another aspect to the question of light that you will need to consider for your experiment—that is its intensity or how strong it is.  As you might expect, natural sunlight is much more intense than any light produced by an artificial source. More intensity means more energy transferred to the plant.  You may find that you will need to compensate by leaving your plants under the "grow lights" for a longer period than your plants growing under natural sunlight experience in the sun. You can find a very good discussion about light intensity and wavelength of "grow lights" compared to natural light in Fluorescent Plant Lighting. This article should also give you some ideas about how to set up your experiment so that you can answer the question you asked Mr. Smarty Plants:  "Will plants grow faster in natural light or artificial light or a combination of both?"  


 

 

 

More Container Gardens Questions

Texas native shade plants for metal troughs in Austin
December 22, 2012 - Interested in finding Texas natives that would do well in metal troughs in the shade.
view the full question and answer

Potted Plumbago, struggling with the heat, in Spring Texas
June 29, 2011 - Why do some of the leaves of my plumbagos that are grown in large, well-draining planters turn brown? The brown starts on the tips, then extends to the whole leaf. They get several hours of west aft...
view the full question and answer

Darkened leaves on blueberry bush
July 02, 2008 - I have a blueberry bush planted in a very large pot. It has been doing very well, producing berries and new growth. All of a sudden the leaves have begun to turn dark. I have it potted in good soil...
view the full question and answer

Care of a sedum indoors
December 16, 2007 - I have a coworker who has trusted her Sedum Burrito plant into my care because it is not doing well in her office. It appears to need repotting, as it is very crowded in the pot it came in and is dif...
view the full question and answer

Use of non-native pothos for outside wall from Las Vegas NV
January 05, 2014 - I am in Las Vegas, NV. I live in a cottage-style apartment so I have a north facing porch with no one on the west so I get some there (and have an inherited cactus probably a yard all round) I would ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center