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
Traditionally, we have used fixtures with T-12 lamps suspended a
few inches above the tops of the plants. However, T-12 lamps are fading
away due to newer lamps that are a better choice for 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
So, does a smaller diameter mean less light? Not at all. In fact,
the T-5 can be the brightest of the three.  Another advantage for these
newer lamps is they use less electricity per lumen. Our traditional
48-inch T-12 is rated at 40 watts. However, there are newer styles of
T-12’s that are 34 watts.  The T-8 is rated at 32 watts and the T-5 at
28 watts.

This sounds too good to be true. Are there drawbacks? Maybe so or maybe
not.  First is cost if you have to replace T-12 fixtures to convert to a
T-8 system.  However, newer fixtures may be able to handle either T-12’s
or T-8’s.  Therefore, if you purchased fluorescent fixtures in the last
few years, check to see if they are rated for T-8’s before replacing
them.  Note that lamp costs are comparable between T-12’s and T-8’s.
The T-5 lamps are significantly more expensive and cost over twice as
much as either a T-12 or T-8.
The question becomes, is it worth it? If you have a T-12 fixture
that is rated for T-12’s only and are satisfied with your results, then
maybe not. However, if you are investing in new fixtures or have
fixtures that can use either T-12’s or T-8’s, then go with the T-8’s.
They will use less energy, last longer and provide more light. b


By:  Ward Upham


Please enter your comment!
Please enter your name here