Grow Light Tutorial

Providing sufficient light for plant photosynthesis of indoor plants is a common problem that many indoor gardeners face. A grow light is an electric lamp, which simulates natural sunshine, and provides the appropriate light spectrum to promote plant growth and blooming. Vegetronix caries innovative innovative grow light systems for indoor potted plants.

Anyone who has played with a prism will know that white light is a spectrum composed of all of the visible colors. The goal of a grow light is to provide just the right amount of light of the appropriate light spectrum to the plant. When evaluating a grow light the following criterion are important to consider:

  • Light Spectrum - Just because a lamp is bright, does not mean that it is providing the correct spectrum. For example, a green lamp is of no use to plant growth, because plants reflect green light, and that is why they appear green. In addition, plants utilize light spectrum that isn't visible to humans, namely, the infrared ultraviolet bands. When selecting a lamp, select one that is intense in the desired spectral bands.
  • Power Efficiency - All lamps generate heat in addition to light. Generated light is measured in lumens. When selecting a lamp, chose one that generates lumens in the desired photosynthesis bands and minimizes the Watts. Since grow lamps are typically constantly on they can be costly to operate, especially the higher power ones.
  • Bulb Lifespan - All bulbs have a finite lifespan. Replacing bulbs can be costly, and so this should be a consideration in making a purchase. Incandescent grow lamps tend to burn out the fastest, since they have a hot filament that burns up over time. Florescent bulbs have decent lifespans, and LEDs typically last a very long time.
  • Aesthetics - This may or many not be important depending on the application. Many of the grow lamps for commercial applications tend to be boxy looking, and just plane ugly. For home decor, the grow lamp should be slender, attractive, and unobtrusive.

Types of Grow Lights

  • Incandescent Grow Lights - These are the most energy wasting of all of the lights and at 750 hours they have the lowest bulb life, since the filament tends to burn out over time. They tend to put out visible spectrum in the red and yellow bands.
  • Fluorescent Grow Lights - Fluorescents grow lamps are typically twice as efficient as comparable incandescent bulbs. They also can last up to 20,000 hours, which is more than 25 times longer than incandescents. Standard incandescent lights can be used to grow leafy vegetables such as lettuce, and spinach and herbs or start seedlings. High output fluorescents produce twice the light output as standards, are slim, but have half the life span. Since they produce white light which is not fully utilized by photosynthesis, they still are not as efficient as they could be.
  • High Pressure Sodium Lights - These tend to produce a yellow spectrum, and so are usually only used in the reproductive or blooming phase of growth. They have long bulb life, but tend to generate a lot of heat.
  • LED Grow Lights - Grow lamps that utilize LEDs are capable of having all of the desired benefits discussed above, without some of the limitations. They are highly efficient, produce a narrow spectrum that can be tuned to optimal photosynthesis absorption, and are compact, and so they can be used to design highly attractive lamps for the home gardener.

LED Grow Lights

Most traditional commercially available grow lights are unattractive, bulky and use excessive amounts of power, and tend to have short life spans as bulbs burn out. With the advent of LEDs many new grow lamps are overcoming these limitations by leveraging their inherent power efficiencies, small size, low cost, and long life.

How LED Grow Lamps Work

The key to LED grow lamp efficiency is that photosynthesis only requires a few spectrum bands. Since plants leaves are typically green, this means green light is reflected, and not used by the plant for growth. Because green light is reflected, a lamp that provides green light is wasting energy. It is common knowledge within the scientific community, that there are only 4 light bands that are necessary for plant growth. The upper blue and ultraviolet bands are most important for plant growth and the lower bands of red and orange are related to plant blooming. LEDs operate in fairly narrow spectrum bands, and so LED grow lamps can target the narrow bands required for photosynthesis and ignore all other bands, thus increasing power efficiency.

Grow Lamp Applications

  • Home herb gardens.
  • Potted plants for home decor.
  • Indoor hydroponic farming.
  • Aquatic plants.
  • Home production of personal use medical marijuana and cannabis.

Grow Light Manufacturers

  • Hydrofarm
  • Sunshine Systems