Plant Growth With Artificial Light & Natural Light

Light

The light that humans and plants "see" is known as visible light. And visible light is composed of seven specific colors arranged along a spectrum. This light spectrum is comprised of the colors red, orange, yellow, green, blue, indigo and violet. Over time, plants have evolved and adapted themselves to make great use of only a few colors within the visible light spectrum. Natural light contains all colors. Artificial lights might not, though many contain the colors truly needed by plants.

Plants typically use two specific colors of light to grow: red and blue. Red light is used by plants for flowering growth, while blue light enables vegetative, leafy growth. Most other colors in the light spectrum tend to be reflected away by plants. Light reflection also helps explain why plants look green to human eyes. The chlorophyll in plants is reflecting green light away. Any light source that can provide red and blue light will work well on plants.

Artificial light of certain types can compete with natural sunlight to provide the colors of light plants need to grow and thrive. Incandescent bulbs provide large amounts of red light but they're also very hot. Heat above a certain point is harmful to plants and can burn them. Standard fluorescent light, also known as cool, white light, provides large amounts of blue light. Plants grow hardily under blue light as long as a little red light is also included.

The benefit to natural light is that you don't need to worry about the proportion of blue light to red light your plants will be receiving. The drawback, though, is that you can't grow plants indoors because natural light will be missing. Plants, though, can grow well under indoor artificial light, including fluorescent lighting. Fluorescent lights also contain a very small amount of red light, though more can be added by using an incandescent bulb occasionally.

Keep in mind that plants also need periods of darkness to grow well. If using fluorescent lighting on plants, about 10 to 14 inches of distance between the lighting and the plants is all that's needed. If you'd like to add a bit more red light, just use a medium-wattage incandescent bulb on occasion. Keep any incandescent lighting at least a few feet away from plant tops. Special plant grow lights are also available to aid in the growing effort.