Many marijuana growers have used fluorescent tubes to cultivate and flower marijuana, but buds grown under these lights tend to be small and loose. This is largely because the intensity of the light (i.e. the amount of light produced by fluorescent tubes) is comparatively low. The light is also produced over a large area. This results in lower amounts of light spread out over a large area and plants that don’t receive adequate light. Self-ballasted high-watt compact fluorescent lamps can screw into incandescent sockets and are good for lighting small marijuana gardens because they emit intense light in a small area.
Although HPS lamps have a higher sticker price than fluorescents, factoring in the cost of electricity makes them a much cheaper option. In fact, HPS lamps produce about two to three times the amount of light per unit of energy consumed. Over its lifetime, the HPS lamp will cost you much less than fluorescent tubes. You can certainly grow marijuana with fluorescent lamps, but the only way to get a higher yield, better marijuana quality, and cheaper overall prices is to go with HPS lamps.
A 1,000-watt lamp produces about 130,000 lumens, while a 72-watt, 8-foot fluorescent tube emits 3,200 lumens and a compact fluorescent emits 6,800 lumens. That equals 130, 45, and 65 lumens per watt respectively. If you throw in electrical costs, the fluorescent is much higher priced. Conventional fluorescent tubes distribute their light over long distances (usually 4 or 8 feet). By contrast, compact fluorescents and HPS lamps have pinpointed directories at about 5 and 9 inches respectively. Gardeners generally use an area measuring about 4’ x 4’. Getting that intensity of light with standard fluorescents is virtually impossible.
Your decision should partly be influenced by convenience as well. It would take thirteen 8-foot fluorescent or 16 compacts to compare to the light intensity of one 1,000-watt HPS. Installing and adjusting just a single light is much simpler than trying to do it with several fluorescent fixtures.