Newer Fluorescent Lights Available for Indoor Gardeners

Many gardeners use fluorescent lights to start young vegetable and flower plants during the spring or to grow certain houseplants all year long. Traditionally we have used fixtures with T-12 lamps suspended a few inches above the tops of the plants. However, there are newer lamps that may be a better choice for some indoor gardens. These are known as
T-8 and T-5 lamps. The number after the “T” refers to the diameter of the lamp in eighths of an inch. Therefore, a T-12 lamp is 12/8 or 1.5 inches in diameter and are what most people are familiar with. A T-8 is
8/8 or 1 inch in diameter, and a T-5 is 5/8 of an inch in diameter.

So does a smaller diameter mean less light? Not at all. In fact the T-5 is the brightest of the three. A T-12 lamp puts out 1,500 to 1,700 lumens for a 48-inch lamp. This lamp has a life of between 10,000 and 20,000 hours. The T-8 lamp produces 3,400 lumens and has a 40,000-hour life expectancy. The T-5 is rated at 5,000 lumens but lasts only 30,000 hours. Well, actually 30,000 hours is a long time. If you had your lamps turned on for 12 hours every day, it would take almost 7 years to reach the 30,000-hour mark.

Another advantage for these newer lamps is they use less electricity per lumen. Our traditional 48-inch T-12 is rated at 40 watts, the T-8 at 32 watts and the T-5 at 54 watts.

This sounds too good to be true. Are there drawbacks? Of course there are. First, you cannot use your existing T-12 fixtures but must use fixtures made for the type of lamp you buy. For example, a T-5 fixture that holds four lamps would cost about $200. About $60 of this cost is the four T-5 lamps included in the deal. A three-bulb T-8 fixture with the three bulbs included costs about the same ($200) but would not produce as much light. However, the T-8 lamps use less electricity per lamp and last longer. If you have done the math, you have noticed these lamps are not cheap. The T-5 lamps are about $15 each and the T-8s run about $20 per unit.
The question becomes, is it worth it? If you have a single fixture and are satisfied with your results, then probably not. If you have a more extensive setup and/or want your plants to be stockier, then this might be of value.


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