Project Grow can help you design a lighting system to meet the needs of any indoor growing project. The most commonly used grow lights are:
High Intensity Discharge - Both Metal Halide (MH) and High Pressure Sodium (HPS) bulbs fall into this category. Their intensely bright light makes them ideal for lighting indoor gardens. Both require Reflector housings and Ballasts to operate. Ranging from 150 watts to 1000 watts, a single fixture can cover from a small self-contained hydroponics garden up to 20-40 sq. ft. Since HID lamps create a great deal of heat, proper venting or even ducting and fans are usually needed.
Metal Halide (MH) - These bulbs produce an intense light of blue-white spectrum, excellent for vegetative plant growth. A plant grown under a metal halide light will often exhibit increased leaf growth and strong stem and branch development. Metal Halide lights are less suited for the flowering and fruiting stages of most plants.
High Pressure Sodium (HPS) - HPS lamps produce an orange light, which simulates the autumn sun. HPS light is best for fruiting and flowering. Fruit and flowers will be larger and more prolific when HPS are used. Flowers and vegetables finished off under HPS will show tighter, stouter blossoms with increased yields. If there is to be only one light source for the entire life of a flowering plant, HPS is the best economical choice.