Selecting the right type of lighting for your indoor gardening project is essential. Fluorescent grow lights can be very effective because they contain the blue light segment of the spectrum that is needed for seedlings, clones and vegetative growth. Typically, a single fixture will provide enough light for small plants, say 8-12 inches. However, 2-3 fixtures can be used together to broaden the area covered and foster vegetative growth up to 24 inches in height.
What’s great about fluorescent plant lights is that they give off very little heat. This
means that you can let the plants grow within just a few inches of the bulbs without
burning the plant. Standard fluorescent grow lights produce double the amount of
lumens per watt of energy as incandescent lights and have an average life span of
up to 20,000 hours.
Standard fluorescent light bulbs come in three sizes, T5, T8 and T12. The “T”
represents the shape of the bulb (tubular), and the number represents the diameter
of the bulbs (in eights of an inch). The T5’s are the newest and most efficient of
the group, and also have a “high output” version that is twice as efficient as the
standard T5.
In the past, fluorescent growing lights were seen as oversized, low output and only good for seedlings. All of this has changed with the advent of the T5 full spectrum and compact fluorescent light (CFL) systems.
These “entry level” fluorescent are perfect for seedlings and veggies like spinach, lettuce and other herbs. Just make to keep the bulbs no more than 4 inches away from the tops of the plants. Standard fluorescent are twice as efficient and produce twice as many lumen as incandescent bulbs. Even more impressive, their life span is roughly 20,000 hours, more than 20 times that of incandescent!
Producing nearly twice as much light as their standard counterparts, high output fluorescents . For example, a 4-foot model with 8 tubes produces the same amount of lumens as a 400 watt metal halide grow light. The benefit of the fluorescent is that it gives off much less heat and spreads light more evenly over the coverage area. High Output fluorescent grow lighting delivers roughly 5,000 lumens per 54 watt 4 ft. tube and have an average life span of 10,000 hours.
T5 fluorescent fixtures come in 2 foot and 4 foot systems containing 1-8 high output T5 fluorescent bulbs with a curved reflector behind each bulb. Since these systems can get a bit pricey, you may want to use a standard fluorescent light for a small number of clones and seedlings. Save this powerhouse for growing big, hearty plants in their vegetative stages up to 2 feet tall. Also, while it is possible to use the T5 fluorescent growing lights for flowering, the typical yield is half as much as you would get using high pressure sodium lights. If yield isn’t your concern, than try out the T5 system for things like leafy vegetables, growing bedding plants, an herb garden, bonsai trees, succulents or even orchids!
Compact fluorsecent fixtures and CFL bulbs provide the widest
range of color spectrums and are extremely versatile because of
their small size and low heat output. These bulbs last about 10,000
hours and are available in three different versions:
Warm/Red (2,700k) – best for promoting flowering and budding
Full Spectrum/Daylight (5,000k) – promotes overall growth
Cool/Blue (6,500k) – promotes overall growth
*Note: The 125 watt fluorescent bulbs produce 8,500 lumens,
while the 200 watt bulbs produce 12,800 lumens.
Many people are seeing great success using the Compact
Fluorescent Grow Systems for shelf gardening because their low
heat emission allows you to place the lights on rows of shelves that
are stacked on top of each other. If you’ve never seen one of these
grow lights in action, they pretty much look like the average energy
saving light bulb you would use in your house.
It is important to mention that the big disadvantage of CFL grow
lights are the relatively poor light penetration and lower overall
efficiency as compared to other types of lighting. For these reasons,
we recommend using a reflector and keeping the light close to
the plants.