T5 setup questions

[Norton]

Wow I am surprised this thread is still hanging around! As the original author, let me say this: all my worries about T5 lights were unfounded. They are an excellent way to grow many types of orchids. Yes they run hotter than regular fluorescent bulbs. However the increase in light output is worth it in my opinion. A four inch fan blowing down the length of the bulbs can help dissipate heat. All of the orchids under my T5 lights are in bloom or spiking. For me the money spent on my T5 setup was one of the best investments I have made in this wonderful hobby.

[Intruder]

Originally Posted by Norton

Wow I am surprised this thread is still hanging around! As the original author, let me say this: all my worries about T5 lights were unfounded. They are an excellent way to grow many types of orchids. Yes they run hotter than regular fluorescent bulbs. However the increase in light output is worth it in my opinion. A four inch fan blowing down the length of the bulbs can help dissipate heat. All of the orchids under my T5 lights are in bloom or spiking. For me the money spent on my T5 setup was one of the best investments I have made in this wonderful hobby.

You probably know that here in Europe the electricity is very (too) expensive. From a economic point of view is it better to use T5 tubes instead of T8? You know also that the possibility of using LEDs for lighting exist (less heat), but their high price still limits their use.

[Ross]

Originally Posted by Intruder

Maybe a beginner question: what is the advantage to use T5 tube? I read they heated more than a T8 tube. For each watts consummated they give more light but if the benefit is lost in heat where is the benefit? Thank you for your explanations.

The heat is not that high ( yes higher than t8 but not as high as HPS or the like). The benefit comes from being able to get lots of light in a small area. Only other way is the so-called "hot lights" High Pressure Sodium or Metal Halide systems) t5 comes in both straight tubes and compact versions. All t5 systems yield high amounts of lux for the energy consumed. Heat is the easiest issue to deal with, normally.

[Norton]

A T5 setup will not only cost more to purchase but it also uses more electricity. My setup uses four bulbs at 54 watts each. I am pretty sure that is more than just about any other fluorescent type light normally used for growing plants. There is one thing to consider though and that is how many T8 bulbs would it take to give the same output as T5? More bulbs would be needed and you will be using more electricity at this point. If you compare how many lumens per watt you will see that T5 is giving a lot of light for the energy consumed. I have no experience with LED so I cannot really comment too much on them.

[johnblagg]

they really are getting led lighting to a much higher ouptput and probably will soon have some worth whils grow light ...look at the newer lcd projectors they have out now using led lamps - they are getting there .They just need to get this much power in grow light version.

they do have cfl grow lights up too 200 watts now also that work great Im sure not as high effeciency as T5s but still very good

[mayres]

That is plenty of distance to work with - I have my 6 tube T5's fixtures about 16-24" from plants with no issues. The phals being shorter plants are at the extreme range and the taller plants closer.

[Ross]

Originally Posted by mayres

That is plenty of distance to work with - I have my 6 tube T5's fixtures about 16-24" from plants with no issues. The phals being shorter plants are at the extreme range and the taller plants closer.

And I'll give my lecture #4 one more time: There's a big difference between accumulated lumens/lux at leaf surface under lights versus in nature or a greenhouse. When the lights come on, it's at full-rated-levels. So if you were to measure 1500 foot-candles at the leaf surface under your light fixture, that's over 10+ hours (usually 12-14 hours.) Now contrast that to a 12 hour day under bright sunlight and you'd see that the early and late hours might only measure 500 or less foot-candles whereas at the high noon hours you might measure 5000 or more foot-candles. The high end of the light will be over a short span of a few hours. The largest share of the day will be at very low levels. The average is what we need to consider, not the peaks. For this reason, most orchidists easily grow and bloom Cats or other "high light" groups under t8 or t5 florescent tubes. I even grow and bloom many genus of cacti under t5 lighting exclusively. I also grow and bloom Paphs, Phrags, Phals, Masdies, etc. under lights as well. It's all in the timing (or "day" length) along with distance from the lights.