T5HO lamps for indoor plants

[zxcvbob]

I live in Minnesota, where the winters are 6 months long. To keep
from going crazy, I do some gardening in my basement. Not cannabis,
(not that there's anything wrong with that) but hot peppers and
tropical flowers and stuff like that. Then seedlings in the spring
while I'm waiting for warm weather.

I want to replace my old HPS fixture (400W security floodlight) with
something like a 4-lamp F54T5 fixture with a 95% reflector, because
they are less expensive to operate, look better, and it's easier to
adjust the height, etc. Where I'm getting stuck is figuring out what
color temperature lamps to order -- 835, 841, or 850? (I could also
order without lamps and buy overpriced 830's locally.) *Have there
been any recent studies on what color triphosphor lamps work better
for plant growth?* I know lumens are calibrated to human eye
sensitivity, and plants have a totally different spectrum sensitivity,
but I'm finding conflicting information on the Internet about what
color lamps plants like.

I've had pretty good luck in the past using a mixture of 830 and 835
F32T8 lamps, overdriven to about 38W each. I will continue using
those fixtures and lamps for my very young seedlings.

The lamp companies don't help much; the spectral distribution charts
are awfully hard to find.

I suspect there is a difference but it's not really significant, and
those are the types of decisions I have the most trouble making.

Any recommendations? Thanks,
Bob

 

[zxcvbob]

My first take is that it doesn't matter, the spectral differences are
fairly small. In this case I think quantity matters far more than
quality.

There are lots of details that impact how effective a light source
will be for plants. "Grow Lights" in general are based on balancing
them all, and I haven't heard of a T5HO version. But I would look hard
before giving up!

Good luck

I found some cheap 1x54W strip lights that come with 6500k lamps
installed (not sure if they are 865 or 765) and I need new lighting
for my garage too. So I wrote to the manufacturer to see what the
operating temperature range is. If they'll start in below zero
weather, I'll get a few of those for the garage, and get a 4x54W
fixture with 830 or 835 lamps to use as a grow light in the
basement. Then I can swap lamps back and forth until I find a
combination I like.

Bob