Lighting Your Indoor Garden

BY MELISSA SUE SORRELLS GALLEY

Want to grow your indoor garden like the guys at NASA? Get yourself some Light Emitting Diode (LED) components. 

Light is, of course, essential to plant growth. Plants convert the energy from light to power their life functions through photosynthesis. And as part of that process, plants synthesize food directly using energy from light. But while natural sunlight contains a complete light spectrum, most plants don't absorb the full spectrum and can't utilize a lot of that energy for photosynthesis. 

 Plants grow with no natural sunlight. (via: hydroponicshabitat.com)     

LEDs are relatively new for many home horticulturists, but they're used  by NASA scientists, who consider them a “efficient and versatile,” because  they're able to refine the spectrum of light emitted to only those that plants actually use for photosynthesis, resulting in quicker growing and ultimately healthier plants. 

In addition to their ability to generate up to 93% more efficient light absorption, LED lights are also highly prized for their low power consumption, low heat production and exceedingly long bulb life when compared to high-intensity discharge, incandescent or fluorescent lights. 

World of Color

Many specialty grow lights are available in different wavelengths, and different wavelengths affect plant growth in different ways. The two most effective and important wavelengths for plant growth are 620-750 nanometers and 450-495 nanometers, which are seen by the human eye are red and blue.

Graph shows wavelengths of light that are actually usable by plants. (via: keystone.edu)   

Photosynthesis works most fundamentally from red light and secondarily from blue light. The red light drives the engine of photosynthesis and also promotes the creation of phytochromes, which help plants determine the time of year and day. By changing the amount of red light, you can make a plant believe it's time to grow, even in the dead of winter. 

Blue light regulates plant development, and the right amount of blue light results in faster flowering and quicker fruit development. Working together in the right combination, blue and red grow lights will not only support indoor plant growth but promote high-producing and blooming plants while simultaneously creating less unnecessary heat and light. 

PAR for the Course

Rather than promoting the specific red or blue spectrums, some specialty grow lights focus on producing high Photosynthetically Active Radiation (PAR) values. PAR measures the amount of usable light that a source can emit, and higher PAR values result in more robust plant growth over a shorter period of time.

Purdue Professor of Horticulture Cary Mitchell studies LED lighting. (via: Purdue.edu)     

By focusing on the spectrum of light that plants can use effectively, these PAR-producing lights can eliminate a lot of heat and energy waste associated with indoor grow lights-they simply don't produce light or heat that isn't directly useful to the photosynthetic process. 

 What are you growing in your indoor garden this winter? Are you using specialized grow lights? Tell us about your experiences in the comments below.