Grow Light Generations

Introduction

The world of grow lights has evolved significantly over time, transforming indoor gardening and revolutionizing plant growth. From the early days of incandescent bulbs to the advanced Light Emitting Diodes (LEDs) of today, each generation of grow lights has brought us closer to achieving efficient and effective indoor cultivation. In this blog post, we will take a closer look at the fascinating history and workings of each grow light generation and explore how they have shaped the world of horticulture.

First Generation: Incandescent

How: Incandescent light bulbs produce light by passing electric current through a thin filament that is heated to a very high temperature causing it to glow.

History: The first incandescent light bulb was invented by Humphry Davy in 1802 using a platinum filament. Davy's bulb was very inefficient and burnt out quickly. In the 1870s, Thomas Edison and Joseph Swan independently developed more efficient incandescent light bulbs. Edison's bulb used a carbon filament, while Swan's used a bamboo filament. Edison's bulb was more efficient than Swan's and became the standard for incandescent light bulbs. Incandescent light bulbs first became commercially available in 1880 and rapidly became the most popular form of lighting. The next major advancement for incandescent light bulbs came in 1904 when tungsten filament was introduced which lasted longer and had a brighter light comparatively. Finally, in 1913 Irving Langmuir figured out that using an inert gas, such as nitrogen, inside of the bulb doubled its efficiency. Scientists continued improving the incandescent bulb for the next 40 years but by the 1950s, we could still only convert roughly 10% of the energy produced by this bulb, into light.

Second Generation: Fluorescent

How: Fluorescent light bulbs produce light by passing electric current through a mercury vapor, which produces ultraviolet light that is then converted into visible light by a phosphor coating.

History: The Fluorescent light bulb was invented in 1896 by Peter Cooper Hewitt. Hewitt's first design produced a blue-green light. Even though Cooper Hewitt's lamps were more efficient, they were not suitable for most uses because of the blue-green light it emitted. It wasn't until 1910 that Edmund Germer developed a way to coat the inside of a fluorescent bulb with a phosphor, which improved the efficiency and color of the light. Then, in the 1926 Jacques Risler developed a way to bend fluorescent tubes into a spiral shape making the even more efficient and significantly more compact. Fluorescent bulbs were eventually opened to the commercial market in the 1930s. Finally, in the 1970s, compact fluorescent light bulbs (CFLs) were introduced offering a smaller and more efficient option than its predecessors. Since, they've grown to be the most common type of fluorescent light bulb.

Third Generation: High-Intensity Discharge (HID)

How: HID grow lights work by passing an electric current through a gas, which produces a bright light. The type of gas used in an HID grow light determines the color of the light produced. For example, metal halide lights produce a white light, while high-pressure sodium lights produce a deep red light.

History: The high-intensity discharge (HID) light bulb was invented in the 1960s by a team of scientists at General Electric. The first HID light bulbs were used in commercial greenhouses, but they soon became popular among home growers as well. HID light bulbs are more efficient than fluorescent light bulbs, and they last longer. However, they can be more expensive. The first HID light bulbs used mercury vapor as the gas. These bulbs produced a blue-green light that was not suitable for most plants. However, in the 1970s, a new type of HID light bulb was developed that used metal halide as the gas. Metal halide bulbs produce a white light that is ideal for plant growth. In the 1980s, a third type of HID light bulb was developed that used high-pressure sodium as the gas. High-pressure sodium bulbs produce a deep red light that is ideal for flowering plants. Today, HID light bulbs are a common sight in commercial greenhouses and home grow rooms. They are a good option for growers who need a bright, efficient light source.

Fourth Generation: Light Emitting Diode (LED)

How: LED lights pass an electric current through a semiconductor material, which causes the material to emit light. The color of the emitted light depends on the type of semiconductor material used. 

History: The first LED light was invented by a British Engineer named Henry Joseph Round in 1907. Round's LED was made of a crystal of silicon carbide, and it emitted red light. In 1962, Nick Holonyak Jr, an American engineer, invented the first practical LED light made out of gallium arsenide which also emitted a red light. Then in the 1970s, scientists began to develop LEDS that emitted other colors of light, such as green, yellow, and blue. Next, in the 1990s, the first commercial LED light bulbs were introduced. Although they were a significant improvement over the previous generations of lights, they were expensive and inefficient. In the 2000s, LED light bulb technology continued to improve and the cost of LEDs began to drop. Finally, in the 2010s, LED light bulbs became the most popular type of light bulb in the world. They are now more efficient and less expensive than predecessors and last much longer. It's fair to say that LEDs have revolutionized the lighting industry (especially grow lights). They are more efficient, longer-lasting, and environmentally friendly than traditional light bulbs. 

Comparison

Conclusion

From the humble beginnings of incandescent bulbs to the high-efficiency and long-lasting LED technology, each generation of grow lights has played a vital role in the development of indoor gardening. As we continue to explore new frontiers in horticulture, LEDs have emerged as the leading choice for growers, offering unparalleled efficiency and sustainability. By understanding the evolution of grow light generations, we can make informed decisions in selecting the most suitable lighting solutions for our indoor plant cultivation.

References

The History of the Light Bulb. (n.d.). Energy.gov. https://www.energy.gov/articles/history-light-bulb

LED Grow Lights for Plant Production - Oklahoma State University. (2017, April 1). https://extension.okstate.edu/fact-sheets/led-grow-lights-for-plant-production.html