FlytrapCare Carnivorous Plant Forums

I have a T12 fixture and a T8 fixture i was wondering do you guys who grow your plants under lights swap out your tubes every year? I've read somewhere that even though the lights still work they the amount of lumens falls off with more time.

Yea they will still work, but I use a lumenmeter to check light intensity once a year, if I see a decrease in the lumens I replace them

What type of meter do you use because my light meter doesn't seem to pick up much from a 6500k bulb? I hold it directly under it and it reads 200 mystery units. I was thinking of swapping out my bulbs when they reach half their rated life of 20000 hours, which for me, comes out to about 2 years. I don't have any scientific evidence to back that...just kind of guessing that's on the safe side.

yeah i used this light meter app on my phone it gives me readings in Lux and even then i think the numbers are low. i put my phone under the lights and i get around 800-100 lux but my plants were doing fine under these t8 bulbs the last growing season.

What application do you use ?

I got this a couple years ago for something or other, I don't remember why I got it. But it works pretty well and isn't too expensive.

Light meters are pretty fun. It's especially informative to take two different areas that both look equally bright by the naked eye and measure the lux. You'd be surprised to see how much lux can drop and you not perceive a drop in brightness.

It's also neat to see just how puny the light output is from a light compared to the sun. Or how much a window reduces the light that reaches a plant.

parker679 wrote: Light meters are pretty fun. It's especially informative to take two different areas that both look equally bright by the naked eye and measure the lux. You'd be surprised to see how much lux can drop and you not perceive a drop in brightness.

I was just reading the other day that you have to double the number of lumens for the human eye to perceive a change and quadruple it for it to appear doubled.

I found this app on the iPhone called light rabbit and I guess the concept is it will give u a lux number through pointing the camera at the light source