Fluorescent Lighting

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Fluorescent Lighting

Post by Weedguru Higher » Sun Sep 19, 2010 10:09 pm

Fluorescent Lighting
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What is a fluorescent light?

A fluorescent light is made up of a glass tube coated with phosphor, which is filled with a mixture of gases. When electrical current is applied, it "excites" the gases, causing the tube to glow brightly. ie: to "fluores".

Types of Tubular Fluorescent Lights

These are the most widely used diameter fluorescent tube size is T-5, T-8 T-10, T-12. Bulb sizes (meaning diameters) vary from .25 up to 1.5 inch, the larger in diameter the larger the fluorescent.

T12s, and to a lesser extent T10s are the biggest bulbs out the mentioned few, therefore the heat is dispersed on a larger surface, so the bulb stays cooler. That means these bulbs can literally touch the plants, the glass stays cool enough to keep from burning the leaves. That can be a huge advantage when it comes to cloning especially, the lights won't wick the moisture up like an HID or even T5s would. These lights can also be pretty effective for veg, though they are less efficient than T8s and T5s.

Standard T8 fluorescent lamps offer better efficiency, lumen maintenance, colour quality, fixture optics and life-cycle costs than antiquated T12 systems. However, several other options now offer even better performance for most applications.

High-performance T8s. Fluorescent lighting technology has achieved new levels of efficiency, colour quality, and longevity in a class of products called "high-performance T8s" (sometimes called "super T8s"). Most of these products carry a price premium, but they're typically more cost-effective replacements for T12s than standard T8s . In many cases, high-performance T8s can also cost-effectively replace standard T8s, potentially making the tens of millions of square feet of commercial space that use electronically ballasted T8 lighting systems ripe for another round of efficiency upgrades. Today's high-performance T8 lamp-and-ballast combinations can improve system performance by 70% to 81% over a T12 "energy-saver" lamp and magnetic ballast combination, and by 23% to 31% over their most common modern predecessor—the standard 700-series, rare-earth-phosphor T8 lamp and standard instant-start electronic ballast combination.

T5 lamps. T5 fluorescent lamps are only available in metric lengths and are therefore not a good retrofit option, but they can be an effective choice in new construction or major renovations. Their efficacy is similar to that of T8 lamps, but their smaller size affords better optical control. The T5 lamp is currently designed for operation only on high-frequency, rapid-start or programmed rapid-start electronic ballasts. T5 lamps also offer high lumen maintenance, putting out as much as 97% of their original light output at 40% of rated life. And T5 lamps are designed for a high optimal operating temperature, which improves performance in enclosed fixtures and warm spaces.

T8s and T5s are skinnier bulbs than the others, and because of that the bulbs get hotter. They are also more efficient that any CFL, T10, or T12. Many T8s and T5s produce about 85 lumens per watt, pitiful in comparison with HID but they are the next best thing (other than pricey LED, and Plasma lights) They can be used for both veg and flower as they are both available in a wide variety of spectrums, and can produce good results in both


Bulb Swapping

T8 bulbs are designed to operate with an electronic ballast. Most ballasts made today are electronic ballasts designed for t8 bulbs. These new type of fluorescents are considerbally cheaper to run then the T12 magnetic ballasts.

T12 bulbs are designed to operate with a magnetic ballast.

It's not a good idea to swap out your T12 bulbs with T8 bulbs when using a older magnetic ballast. The bulbs may light but the life and quality of the bulb will be reduced considerably.

You can get T8 light fixtures for a relatively cheap price at Home Depot or lowes.

Lumen Maintenance

Also known as lumen depreciation, lumen maintenance describes the rate at which lamps lose their ability to produce light. Lumen maintenance is measured at 40 percent of rated life and determines useful lamp life and light levels. A major maintenance advantage for using T8 lamps in place of T12 lamps is their superior lumen maintenance.

The T8 lamp declines slowly to about 92 percent of its initial lumen output and then remains steady. The T12 lamp declines more quickly to about 80 percent of its initial output and then continues to decline.

T5 bulbs slow to about 97% of its initial lumen output and then remains steady making the T5 the BEST bulb to use. Only problem with T5 bulbs is that they won't work with standard fluorescent fixtures. A T5 light fixture which has a T5 ballast must be purchased when using T5 bulbs.

If your already using T8's I don't think its worth the cost to change over to T5's. T5's are only better by 5%. But if your in the market for fluorescent lights I would choose the T5.

What are lumens?

Lumens are the unit of measure that state the amount of light output produced by a light source. The higher the lumens, the greater the light output. The standard fluorescent tube should produce at least (3000-3300) lumens.

What is a Kelvin scale?

One way light is measured is on a Kelvin scale. A Kelvin scale expresses the exact color the bulb emits. Bulbs in the range of 2700 to 6500 on a Kelvin scale is ideal for growing marijuana. Plants respond not only to the quantity of light, but also the quality.

6500K is great for vegetative growth. 3000K is warm white, sometimes called soft white, an slightly orange colour which is optimum for flowering. 4100K is cool white, the traditional colour for fluorescents which is used for basic office or shop lighting. 6500K is often called daylight, it is close to the colour of direct sunlight, in practice it is more blue than direct sunlight. Get cool whites or maybe daylights for plants.


What color spectrums are available in fluorescent bulbs?

Fluorescent bulbs have the most range of spectrums than any other bulb. The spectrum comes in various spectrums, determined by the type of phosphor with which the bulb is coated. The following fluorescent types are as listed, along with what they may accomplish for you.

Full spectrum fluorescent bulbs have all the colors of the Kelvin scale. This bulb is good for vegetation stage. Note: This spectrum fluorescent is used in hospitals nationwide in helping people with "depression".

Wide spectrum fluorescent bulbs will restrict development of side branching, helps plants mature faster. This fluorescent is high in the red, orange and yellow color range. In fact, this fluorescent is the highest than all other fluorescent bulbs. As a matter of fact, this fluorescent is much like an HPS color range, which makes it the best all around choice for flowering stage.

Daylight spectrum fluorescent bulbs are very high (if not the highest) in the blue range on the Kelvin scale. This fluorescent promotes an arctic blue look. I suggest this fluorescent during vegetation stage.

Cool spectrum fluorescent bulbs will promote multiple side growth, nice green foliage. This fluorescent is high in the blue range, giving off a bright white appearance. I suggest this fluorescent for vegetation stage.

Warm spectrum fluorescent, will promote extra thick stems and branches, and will give you about 5% denser buds than other spectrums. This fluorescent is high in the red range on the Kelvin scale.


Manufacturers use standardized names such as Daylight and Sofwhite to designate a tube that has a certain degree of whiteness. Each name corresponds to a tube that emits light in a particular combination of color bands. For example, Cool White emits more blue light than other colors and appears blue-white. By combining tubes that emit more blue light with tubes that emit more red light, the tubes complement each other and produce a more natural spectrum for healthy plant growth. More "red light" than "blue light" sources are needed to foster healthy growth, so use two red tubes to each blue tube.

The best combinations are either Warm White or Soft White (red) tubes used with either Cool White or Daylight (blue) tubes. These four tube types are common, much cheaper, and when used in combination, will give you a better return than any of the more expensive gro-tubes or natural-spectrum tubes. Any hardware store carries these common lighting tubes, and the cost may be less than a dollar each.

Do not use tubes with "deluxe" in their designation. They have a more natural spectrum but emit considerably less light. Preferably, buy "Cool White" since it emits 50 percent more light than "Cool White Deluxe."

The real advantages of fluoros come from there selection of sizes, bulbs, and power use. It gives the grower the chance to really customize their lighting the way that suits their needs, by mixing spectrums for example, or adding a few UVB bulbs. Fluros can be great for sidelighting and lighting up any dim spots on the plants as they are relatively easy to move around, and can stay within a few inches.

Fluorescent Tubes Specifically Designed For Growing


Several lighting manufacturers make tubes (gro-tubes) the produce much of their light in the critical red and blue bans. (Plant-gro (GE), Gro-Lux (Sylvania), Agro-Lite (Westinghouse), and gro-lum (Norelco) are examples, and they look purple or pink. Vita-lite and Optima (Duro-test) produce a white light with a natural spectrum very similar to daylight. Duro-test blubs are more expensive than other tubes but they last twice as long.

Theoretically, these tubes should work better for growing plants than standard lighting tubes. However, some standard or regular fluorescent tubes used for lighting actually work better for growing plants than more expensive natural-spectrum tubes and gro-tubes specifically manufactured for plant growth. The reason is that regular fluorescent produce more light (lumens), and overall lumen output is more important for growth rate than a specific light spectrum. To compensate for their spectrums, use them in combinations of one "blue" fluorescent to each one or two "red" fluorescent (Box B).

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