Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

convenience of using these bulbs. A 1000-watt HP sodium bulb produces 140,000 initial lumens. A MH to HPS conversion bulb produces 130,000 initial lumens. If you only want one lamp, a conversion bulb is a fair choice.
Metal Halide to HP Sodium
    The White Ace (Iwasaki) and White Lux (Venture) are conversion bulbs. They have a metal halide spectrum and are used in an HPS system. The bulb converts from HPS to MH and produces 110,000 initial metal halide lumens.

Mercury Vapor Lamps
    The mercury vapor lamp is the oldest and best-known member of the HID family. The HID principle was first used with the mercury vapor lamp around the turn of the 20th century, but it was not until the mid 1930s that the mercury vapor lamp was really employed commercially.
    Mercury vapor lamps produce only 60 lumens-per-watt. A comparison of the spectral energy distribution of the mercury vapor and the photosyn-thetic response chart will show this is a poor lamp for horticulture. It is expensive to operate and produces a spectrum with a low PAR value.
    Lamps are available in sizes from 40 to 1000-watts. Bulbs have fair lumen maintenance and a relatively long life. Most wattages last up to three years at 18 hours of daily operation.
    Bulbs usually require separate ballasts, however there are a few low wattage bulbs with self-contained ballasts. Uninformed growers occasionally try to scrounge mercury vapor ballasts from junk yards and use them in place of the proper halide or HP sodium ballast. Trying to modify these ballasts for use with other HIDs will cause problems.

Conversion bulbs make it possible to have both metal halide and HP sodium spectrums at the expense of electrical efficiency.

Fluorescent Lamps
    Fluorescent lamps have gone through major changes in recent years. New bulbs produce more light. Most growers use fluorescents to grow clones and small vegetative plants and maintain mother plants. Some growers even use them to flower a crop. Fluorescents are available in many different spectrums, some almost identical to natural sunlight.
    Fluorescent lamps are long glass tubes that come in a wide variety of lengths, from one to twelve feet. The two- and four-foot tubes are the easiest to handle and most readily available. Two four-foot fluorescent bulbs in a shop light fixture cost from $20 to $30.
    Fluorescent lamps work very well for root cuttings. They supply cool, diffused light in the proper colorspectrum to promote root growth. Use any “daylight spectrum” fluorescent lamp to root cuttings. Fluorescents produce much less light than HIDs and must be very close (two to four inches) to the plants for best results.
    Using fluorescents along with HIDs is awkward and problematic. When using them in conjunction with HIDs, fluorescents must be very close to plants to provide enough intense light to do any good. Fixtures may also shade plants from HID light and generally get in the way.
    Plants will flower under fluorescent lights. The buds will be small and light, but, with enough fluorescent light, you can grow a mature crop. The grow show will have to literally be lined with fluorescents.
    Fluorescent tubes are available in so many different wattages or outputs that they are hard to track! All fluorescents require specific ballasts. The old standard (T12) tubes use about 10 watts per linear foot. A two-foot tube uses about 20 watts, four-foot: 40 watts, etc. The most common bulbs used for growing are available in lengths from 15 inches (38 cm) to four feet (120 cm). Lamps are available in very low to more than 50 watts. Circular fluorescent tubes are available but used by few growers.
    Power twist, or groove type, lamps offer additional lumens in the same amount of linear space. The deep wide grooves give more glass surface area and more light output. Several companies market variations of power twist fluorescents.
    Black light fluorescent lamps emit ultraviolet (UV) rays through a dark filter glass bulb, but they are not used to grow cannabis. Ultraviolet light is supposed to promote more resin formation on buds. However, all known experiments that add artificial UV light in a controlled environment have proven that it does not make any difference.
    Most of the major lighting manufacturers–GE, Osram/Sylvania, and Philips–make fluorescent lamps in a variety of spectrums. The most common are Warm White, White, Cool White, Full Spectrum, and Daylight. See chart for Kelvin temperatures. Sylvania has the GroLux and the Wide