T5HO 4' fixture bulb longevity

[derv88]

Super confused. I bought a T5HO 4' fixture and when it was new it read 2500 FCs.

Less than 6 months later, my readings are at under 1500 FCs.

Is this normal? Do these fixtures get shipped with cheap bulbs like Chinese batteries in toys or remotes?

I can't figure this out.

Thanks in advance!

[naoki]

That seems to be extreme. Which bulbs (and fixture) do you have?

Here is my measurement (13h/day):
Cheap T5HO "Plant" bulbs and longevity

79% in fc (and 70% in PPFD) after 5 months. 60% in your case.

I was pretty disappointed with my measurement, so I started to keep track the decay of each tubes more systematically now. Some data on the web indicates that T5HO lasts a bit longer than T8, but it may decline pretty fast in real world examples.

[derv88]

It's just a standard Sun blaster or similar fixture. In fact, it's four individual 4' T5HO fixtures each with their own reflectors.

The Cattleya shelf is what I'm most concerned about, need to get those light levels up where they should be. How to do that?

Does indoor growing of Cattleya and other higher light plants require a different solution then fluorescent - like a HPS?

[katrina]

The longer run time (12-14hrs) will compensate for the less than ideal fc levels.

In nature...outside...it's not a consistent level of light due to clouds and whatnot but under lights it's consistent and that consistency is cumulative. I've been growing and blooming catts under HO T5s for several years now.

Most people recommend switching out the bulbs every year.

BTW -- I go a bit against the "norm" and I have my bulbs on an every other year switch out and I run them for only 10hrs a large part of the winter. The plants are only inside for about 8 months of the year...I don't know if I could get away w/this schedule/routine if they were under the lights all 12 months.

[naoki]

Katrina (and many others) have lots of nice high light plants grown under T5HO! In addition to the longer day length, if you can put the plants closer to the light source, you get more light, too. But you need to watch out for the heat.

In a long run, HPS (not the older ballast) or high-quality LED is cheaper. For me (100% artificial light), DIY COB-LED with Cree CXA3070 or Bridgelux Vero 29 (which I'm adding Vero 29 to my grow tent pretty soon) is the sweet spot. 3x 50W of COB-LED (about $60 each) easily replace 4x 54W T5HO. Initially, it is a bit more expensive, but it becomes cheaper after 2-3 years (I calculated the pay-back period, but I forgot the exact number).