Natural lighting is not the only source of lighting in hydroponic gardens because some gardens use a mix of natural and artificial light and some even use artificial lighting completely. Crops utilize different parts of the light spectrum at different stages of growth. The lights used in hydroponics are called "grow lights", appropriately named because they are designed to emit light that make plants grow! Because synthetic lights can't cover the full spectrum that natural sunlight can, it's important to use the right kind of grow light for the kinds of plants you're raising, and it's important that the correct lighting be used at the right stage of growth. In order to make it simpler for you to select the right type of grow lights, here are some useful details.

For plants that are on the early stages of growth along with leafy plants, the perfect grow lights are those lights that fall within the blue-white color spectrum. Metal Halide (MH) bulbs are very good at supplying this type of light. These bulbs can burn hot but does not require close proximity to the crops in order to provide adequate ligthing, these bulbs are otherwise known as High Intensity Dishcharge bulb or HID. Plants that are subjected to the MH bulbs have the tendency to grow thick, leafy, and compact. MH bulbs are used as the primary lighting supply in many gardens.

During the blooming phase, plants draw more from the orange-red side of the spectrum. During the blooming phase plants will benefit more if you use one kind of HID grow light called the High Pressure Sodium bulbs or HPS. Because of their restricted spectrum, HPS bulbs are not a good choice as a primary source of light, but are best used as supplemental to other kinds of lights (like MH), or to supplement natural sunlight. Otherwise, your plants will grow abnormally tall and thin.

If you are mainly growing seedlings (or if you have a separate area for the seedling stage of plants), a great choice is standard fluorescent lighting, placed close to the seedlings. Standard fluorescent lights supply a good amount of the lighting spectrum in low intensity which is an ideal condition for seedlings. They also emit low heat, so they can be placed close to the young plants without burning them. In other applications, the low intensity of standard fluorescent bulbs is not very conducive to growth.

A blend of different grow lights are often used in various hydroponic gardens, but if money is an issue then you can usually use a high-output fluorescent lights as grow lights. Unlike standard fluorescent grow lights, the high-output bulbs provide a more intense light with low heat, and can be arrayed to cover almost the entire spectrum of natural light. These bulbs may not be as intensive as HID bulbs but these high-output bulbs are more affordable and because it produces little or low heat you can place these bulbs close to the plants and compensate for the low intensity and the results are still excellent.

Selecting the right type of grow light for your hydroponic garden can be intimidating, but knowing how different types of light help your plants grow will help you pick the right grow lights for your garden.