METAL HALIDE LAMPS - are blue-orientated in the spectrum. It is the best type of light to be used as a primary light source (if no or little natural sunlight is available). This type of lamp promotes plant growth. They are most often used in athletic facilities. Metal Halide lights are quite popular with reef aquarists, who need a high intensity light source for their corals.

HIGH PRESSURE SODIUM LAMPS - These lamps are red/orange in the spectrum. They are the best lamps available for secondary or supplementary lighting (used in conjunction with natural sunlight). This type of light promotes flowering / budding in plants. It is ideal for Greenhouses / Commercial growing applications.

Deciding on the proper lamp to purchase is a daunting and difficult task. Light is the number one limiting factor next to genetics that will determine harvest size and quality/quantity. First things to consider are the requirements of the plant you want to grow, what spectrum and light intensity does it grow best in? A majority of plants grown will do best under a combination of MH and HPS lamps. Many 1 lamp gardeners will use a MH lamp for the vegging and early to mid flowering growth stages, then switch to an HPS lamp for late flowering. This technique simulates nature closely.
Lighting suggestion - is to purchase a 600 or 1000 watt HPS ballast and reflector, a quality HPS bulb, as well as a conversion MH bulb. This will allow you to switch out the bulbs for different stages of growth. This has been the most popular solution used by our customers thus far.
Hood suggestions - horizontal or vertical? This is always the question, and are answer is this. If your major concern is efficiency and maximizing each lights output then go with a vertical parabolic hood. If you are concerned about heat buildup then a horizontal hood equipped with flanges to attach tubing and a fan so you can exhaust the heat away from the growing area. Visit the reflectors page here...