Some more northern parts of the world don't offer enough light for many plants in the winter. By using grow lights, either as a main or supplemental light source, you can grow larger plants with more flowers. There are several common types of lighting for indoor plant growth.
An advantage of fluorescent lighting is that there are a wide range of lighting tubes available. You have a choice of warm white, cool white and wide-spectrum tubes to choose from.
Wide-spectrum tubes are good if you are growing a combination of green leafy plants and flowering plants. A higher percentage of warm white bulbs in your light mix will increase the red end of the light spectrum, which is better for flowering plants. Using cool white bulbs have more light at the blue end of the spectrum--which encourage more green, leafy growth.
High Intensity Discharge (HID) Lamps
High Intensity Discharge lamps produce more light per watt of power consumed and are often more economical to operate than any other type of lighting. Installation costs, however, are higher. There are two types of HID lamps: Metal Halide (MH) and High Pressure Sodium (HPS).
Metal Halide HID lighting produces more blue light--best for growing green leafy plants and vegetables. MH is best in situations where no sunlight falls on the plants.
High Pressure Sodium produces an orangish-red light that is excellent for flowering plants. HPS lights are the best used as supplemental lighting in an area that gets some natural sunlight.
Incandescent grow lights are the least expensive of all indoor grow lights. They are also the least efficient, as they use the most electricity per lumen of light output. Incandescent bulbs produce light skewed toward the red end of the spectrum and are very good for encouraging flowering. Because they are hot, try to keep the bulbs behind a protective plastic or glass plate to prevent leaf or flower scorch. Starting with incandescent lights is an inexpensive way to start offering extra light for indoor plant growth; however, moving to compact fluorescent bulbs will be cheaper for more long-term use.