How Do Grow Lights Work?

Grow lights are artificial light sources designed to mimic the natural light a plant would typically receive from the sun, so that it can be grown without total reliance on natural sunlight. This allows gardeners to grow plants inside as well as in outdoor greenhouses where grow lights can act as a supplementary source of light. Plants usually rely on sunlight for photosynthesis, which is the process plants use to create their own food utilizing the energy provided by the sun. Understanding this, grow light manufacturers have developed many different types of grow lights; all attempting to emit light in a chosen spectrum that can best give plants the most intense and highest quality light possible.

A grow light will be designed to either mimic the spectrum of the sun, or will incorporate a spectrum that has proven to be the most beneficial for a specific plant species. Since a plant may require different types and amounts of light at different growth periods, some indoor gardeners will have different types of grow lights designed to give the plant the best light possible throughout all stages of growth.

HID Grow Lights
One of the most tried and trued grow light types is the HID grow light, or high-intensity discharge. HID grow lights are an electrical gas-discharge light, which utilizes a tube filled with gas and metal salts that are excited when an electrical current is introduced, thus generating light. The HID grow light replaced fluorescent grow lights and became the most popular choice for indoor gardeners as the technology became more affordable. HID lights today are still some of the most efficient lights on the market in terms of lumens-per watt, however, great leaps and bounds in LED grow light technology have evened the playing field, and it is likely that in the near future, LED grow lights will replace HID as the grow light of choice. There are many types of HID grow lights, including Metal Halide, High Pressure Sodium and the newer Ceramic Metal Halide.

Traditionally, metal halide lights are best for vegetative growth while HPS grow lights work better for flowering. Because of this, many people will switch the bulbs in their HID grow light system, while keeping the same housing and ballasts.

LED Grow Lights
LED grow lights use what are known as light emitting diodes (LED) to generate light. LED lights utilize a semiconductor and electroluminescence to generate light. In sophisticated LED grow lights, tiny reflectors and other engineered parts help to amplify that light and make it more focused. LED grow lights offer the advantage of not requiring ballast, and instead can be plugged directly into a regular wall outlet. Many strides in LED grow light technology have taken place in the last few years, evening the playing field between itself and the tried and true HID grow lights that are most commonly found in indoor gardens across the country.

One big advantage of an LED grow light is that the LEDs used can be engineered to emit very specific wavelengths of light, giving more control to the grower who can then learn what configurations work best for his given species. This strategy can even be effective at the phenotype level, if you are breeding your plants and taking in enough data to make informed decisions.

Fluorescent Grow Lights
Fluorescent grow lights used to be the most common grow light on the market, before the advent of newer and better technologies like HID grow lights and LED grow lights came about. Fluorescent grow lights excite mercury vapor contained in a glass tube with an electrical current, which causes the gas to emit photons at ultraviolet frequencies. These ultraviolet photons are then converted into visible light by a lining of phosphorous which coats the inside of the tube. Now that you know more about grow lights, check out our selection of grow lights, lamps and ballasts. We offer the best selection of HID grow lights, LED grow lights and fluorescent grow lights at a fraction of the price you’ll see in other online hydro stores.

We also offer grow light types that we didn’t cover in this article, such as T5 grow lights, Induction and Plasma grow lights. We will cover those grow lights in a future article, but that doesn’t mean you can’t go check them out now!