Lighting helps growers extend the growing season. This is especially important for growers of hydroponic produce, such as lettuce and tomatoes, for it allows them to grow indoors year-round rather than be controlled by the seasons. You can select from different types of lights, and each serves different purposes.
HID, or high intensity discharge, lights are "the most efficient way to convert electricity into light that is available to the consumer," according to ACF Greenhouses. HID lights come in two forms, metal halide and high-pressure sodium. The metal halide bulb emits light in a blue spectrum, which is good for growth of the leaves and can help keep the plants more compact. High-pressure sodium lights have a red-orange light, which help to promote more budding as well as flowering.
Fluorescent Grow Lights
The lights have improved over time, so that they are able to produce up to 90 lumens for each watt. They do not produce as much heat as the HID bulbs. The color the bulbs emit encourage the plants to grow, and because they are not hot, you can hang them closer to your plants.
Incandescent Grow Lights
These lights are not efficient as fluorescents. They use more energy and are good mainly as supplemental lighting. CFL bulbs, compact fluorescents, are better, and their lights emit colors that the plants like.
LED Grow Lights
These innovative lights are the coolest and are extremely efficient in the about of lumens per watt.
This bulb can be used in either a high-pressure sodium ballast or a sodium ballast. This can be a cheaper alternative than buying different ballasts for each type of bulb.