How to set up lights for supplemental greenhouse lighting?

11 years ago

I've been using 20/4 and 16/8 light cycles(flourescents) with success on freshly germinated pepper seedlings that I have indoors in a grow tent. I recently purchased some led spot lights that I hung from the roof of my greenhouse and im intending to use them as supplemental light.(Picture attached) Does anyone have any experience using supplemental light for peppers?

The area I live in is a beach type area that varies from sunny days to foggy days. I built the greenhouse specifically for growing hot peppers so Im hoping that the supplemental light will help with the foggy days. Ive got the temps and humidity dialed so far.

Ive read that peppers are not photoperiod sensitive, so a 16/8 cycle throughout the year is ok then? My ultimate goal is to simulate a tropical environment year-round and really push the peppers to be perennial, to get them to grow as large as possible and to grow the perfect pepper...

Thanks,
Little Pepper Boy

Comments (3)

Jeff_H
11 years ago
First off, I love the green house. Very neat and organized with plenty of room.

I doubt those lights will do much good way up there. I'd lower them to within a few inches of the plants if I were you. Just like in your indoor grow room, if you want the lights to do some good, they have to be close.
littlepepperboy
Original Author
11 years ago
Hey Jeff_H,
the distance of the light to the plant is also something Ive been trying to dial in, While it seems counter-intuitive to put the lights so far away, Im trying to find the balance between distance and interference with natural sunlight. Maybe Im wrong with this, but the sunlight that comes through 50% of the time is much brighter than the LED will ever be. When I position the LED spot very close, you can see a noticeable shadow from the overhead light diffusion created by the greenhouse(even when it is foggy). After looking into supplemental light, i noticed most other big greenhouse producers use LED's in a way that is unconventional to indoor grow operations and position the lights at a significant distance. (See photo from commercial greenhouse) I have the cords configured so its easy to drop the lights but the focus becomes VERY limited to a small central circle. these are advertised as LED spot lights so Im not expecting a lot of output. Just enough is what im looking for.
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DMForcier
11 years ago
> "When I position the LED spot very close..."

Well that's the problem - they are spots, not floods. The projection pattern is solely due to the optics of the reflector. If you want general illumination - like the panel floods shown above - you need different fixtures. There are two ways that the beam pattern is specified. One is a three character code, the other is a number of degrees. Anything over 35ÃÂ° is a flood.

Naturally as the beam broadens the point illumination decreases, so you have to balance beam (dispersion) angle, distance, lamp intensity, number of fixtures, etc. And there are beam shapers that, for instance, change the pattern from a circle to a rectangle. Lighting design is a rather interesting corner of architecture.

BTW, the shadow thrown by the fixture will move as the sun moves, so it isn't a big deal.