Construction and Operation

Fluorescent lamps create light by passing electricity through gaseous vapor under low pressure.

Like the HID family, fluorescents require an appropriate fixture containing a small ballast to regulate electricity and household electrical current. The fixture is usually integrated into the reflective hood. There are several types of fixtures. The most common fluorescent bulbs used for growing are hooked to sockets with bi-pin connectors. If purchasing new tubes, make sure the bulb fits the fixture. The fixture may contain one, two, or four tubes.

A ballast radiates almost all heat produced by the system. The ballast is located far enough away from fluorescent tubes that plants can actually touch them without being burned.

Ballasts will normally last 10-12 years. Used fluorescent fixtures are generally acceptable. The end of a magnetic ballast's life is usually accom panied by smoke and a miserable chemical odor. Electronic ballasts simply stop. When the ballast burns out, remove it and buy a new one to replace it. Be very carelul if the ballast has brown slime or sludge on or around it. This sludge could contain carcinogenic PCB's. If the ballast contains the sludge, dispose of it in an approved location. Most modern fluorescents are self-starting, but older fluorescents require a special starter. This starter may be integrated into the body of the fixture and hidden from view, or be a small metal tube (about 1 inch [3 cm] in diameter and 0.5-inch long [1 cm]), located at the end of the fixture on the underside. The latter starters are replaceable, while the former require a trip to the electrical store.

If your fluorescent fixture does not work, and you are not well versed in fluorescent troubleshooting, take it to the nearest electric store and ask for advice. Make sure they test each component and tell you why it should be replaced. It might be less expensive to buy another fixture.

The tubular glass bulb is coated on the inside with phosphor. The mix of phosphorescent chemicals in the coating and the gases contained within determine the spectrum of colors emitted by the lamp. Electricity arcs between the two electrodes located at each end of the tube, stimulating the phosphor to emit light energy. The light emission is strongest near the center of the tube and somewhat less at the ends. If rooting just a few cuttings, place them under the center of the fixture for best results.

Once the fluorescent is turned on, it will take a few seconds for the bulb to warm-up before an arc can be struck through the tube. Fluorescents blacken with age, losing intensity. Replace bulbs when they reach 70 percent of their stated service life listed on the package or label. A flickering light is about to burn out and should be replaced. Life expectancy ranges from 9000 hours (15 months at 18 hours daily operation).

Compact FSuorescent Lamps

Available since the early 1990s, compact fluo-

riuorcsœnt lamps are great for rooting cuttings. Some people even use them to grow cannabis. Buds that flower under fluorescents lack density and weight.

Warm white (7700 K) fluorescent spectrum

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Cool white (4100 K) fluorescent spectrum

Cool white (4100 K) fluorescent spectrum rescent lamps (CFL) are linally available in larger wattages. The larger CFL's are having a major impact on small indoor grow shows. CFL's are similar to long-tube fluoresceins but boast increased power, smaller size, and an electronic ballast that ensures longevity and precise spectrum rendition. Although not as bright as HID's they are available in Cool White and Warm White spectrums and generate little heat. Compact fluorescent lamps are perfect lor growers with a limited budget and a small space. They run cooler than HID's and require minimal ventilation.

When CFL's were first introduced, wattages were too small, and bulbs did not emit enough light to grow cannabis. New large-wattage CFL's are much brighter than smaller, low-wattage CFL's. Several years ago, European companies started selling 55-watt CFL's and Home Depot began to sell a 65-watt CF flood light for $30. Soon alterward 95, 125, and 200-watt CF lamps made in China became available in North America and Europe. The new lamps changed the way growers looked at CFL's. The new CFL's provide enough light to grow cannabis from seed to harvest.

Compact fluorescent lamps used to grow cannabis are available in two basic styles and shapes. Modular CFL's have independent bulbs and ballasts that can be replaced separately. The bulb is shaped like a long "U" with a two- or four-pin fixture (these lamps are designated "1U"). The 20-inch (50 cm) long "11T 55-watt, dual-pin base bulbs are common in Europe. Normally, two 55-watt lamps are placed in a reflective hood. Shorter U-shaped bulbs are common in North America, the United Kingdom, Europe, Australia, and New Zealand.

The second type consists of miniaturized fluorescent tubes packaged with an attached (electronic) ballast. The short lamps consist of several U-shaped tubes (designated 4U, 5U, 6U, etc., for the number of U-shaped tubes) that measure from eight to twelve inches (20-30 cm) not including the two- to four-inch (5-10 cm) attached ballast and threaded base. Smaller wattages fit into household incandescent light

Daylight (6400 10 fluorescent spectrum

Warm white (7700 K) fluorescent spectrum

Daylight (6400 10 fluorescent spectrum

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