This is what is in The New Seed-Starters Handbook by Nancy Bubel

"Breaking Dormancy

Light. Subjecting the seeds to light-even a dim continuous light or sudden bright photoflash-will sometimes help, especially with lettuce. Germination depends on total amount received. The dimmer the light, the longer the necessary exposure.

Red Light. Exposure of some seeds to red light (660 nanometers) promotes seed germination. Experiments with lettuce bear this out. However, far-red light (730) nanometers) has been found to inhibit seed germination. Practically speaking, this means that seeds that are difficult to germinate will often do better under fluorescent plant lights. Some seeds won't germinate when shaded by leaf cover, probably because the leaves filter out helpful rays while allowing the inhibiting far-red light to reach the seeds."

In addition, these guys do an excellent job of explaining grow lights and options
http://www.littlegreenhouse.co...

JUst bumping an oldie up.
LOwes has a red light .......short one ........$60. CDN

Joannabanana said:This is what is in The New Seed-Starters Handbook by Nancy Bubel ..."Breaking Dormancy ...
In addition, these guys do an excellent job of explaining grow lights and options
http://www.littlegreenhouse.co...

There is a lot of misinformation or disinformation in both the book and on that website. Notice that the copyright dates on the website omit a date. Usually a copyright has a date. That "new" book was published in 1988, and its information is hopelessly out-of-date.

No disrespect here is intended by me, but this referenced information wasn't even valid on the original posting date, and I feel it appropriate to at least warn the readers here to be wary. And also be wary of what I am saying, because being wary of what you read on the Internet is a good policy.

ZM

Thanks
I bumped it up after seeing the red LED lamp at Lowes.
ANd thought there would be discussion of red light and plants.

I am wondering if that red LED would make Geraniums bloom earlier ???

I tried colored lights.. didn't see any difference

White light contains red light, along with blue light and green light. Warm light fluorescents, like the 3400K bulbs, do seem to accelerate the blooming of my indoor zinnias, and they contain somewhat more red light than the cooler white bulbs.

Since plants don't need green light (that's why they are green -- they reflect the green light rather than use it), some indoor growers use lights that omit green light, and the resulting combination of red and blue light has a hideous purple appearance, in which the green plants appear black. I use white fluorescent lighting, to satisfy both me and my plants.

ZM

Did a small study while working at Longwood Gardens in the early 70s, under red light the plants appeared to grow taller and faster and germinate earlier than like seeds.

We have a sunroom in this house .. last year I tried a led with blue and red .. wasn't the highest priced thing .. and burned out in 2 months .. got a refund from Amazon.. so not sure with the low quality.. what was the deal .. but I didn't see any difference with winter low light .. and that added in growth to the plants I over wintered

PRobably not worth $60

I have Daylight LEDs so will just stay with that.
ALso have T5 HO. In those NAno boxes. SUnblasters

I still use T8 4-foot fluorescent shoplights for my indoor plants.

They are not the latest thing, but they are relatively inexpensive, and work well for me. I use steel chrome wire shelving for my plant stands.

ZM

@ZenMan I was wondering, how often these T8 lights need to be replaced? I recall, that some fluorescent type lights, need replacement, as their light intensity decreases over time & with use. Or is it different, with T type lighting?
Happy New Year ! Thanks, Shawn

Hi Shawn,

" I was wondering, how often these T8 lights need to be replaced? "

I only use my T8 fixtures about half of a year, when I am doing my indoor gardening. I don't use them during warm weather when I am gardening outdoors.

I haven't noticed any decline in their light output over the years. One does occasionally burn out, but that is an exception. They are rated at 20,000 hours of service. Many of my original bulbs that I purchased in 2005 are still in service.

And I have been overdriving many of them. I assumed that since the overdrive modification effectively doubles the light output, that it would halve the bulb lifetime. That is apparently not the case. Over-driving probably decreases the bulb life some, but apparently it isn't a drastic decrease. I am still quite pleased with my T8 shoplights. I plan to make the over-drive modification to some more of them in the next few weeks.

Happy New Year !

ZM

@ZenMan Thanks. I just wondered, as I had seen it mentioned, about the eventual decrease in lumens, or something to that effect. I guess if was all that much loss in effectiveness, you would notice a decrease in your plants, from when you first started growing under lights, as compared to now. I would imagine, the expense of some spectrometer, or other such light measuring devices would be more costly than just buying some new light bulbs! I suppose the whole idea, was about exposure to "red" light, but ultimately, for the plants, isn't it more about exposure to Ultraviolet light, from the sun? I know there is UVA & UVB , rays. But I do think that exposing seeds to sunlight, can help those that need it to germinate, while others actually require darkness.

Hi Shawn,

I actually have a light meter that I needed to use with an old film camera back in the days before digital cameras. It measures in foot candles. I did use it early on to calibrate my plant lighting. I think that zinnias would do OK with 300 foot candles on their leaves. However, I wanted to get as much as 500 foot candles on the leaves of my zinnias. Overdriven T8s, four fixtures per shelf, and with chains putting the 8 tubes only a few inches from my plants raised that intensity to about 1000 foot candles at the leaves. But that was not a requirement.

1000 foot candles sounds like a lot, except that outdoors in the daylight on a sunny day, plants are getting 3000 to 5000 foot candles on their leaves. But apparently my indoor zinnias are reasonably happy with light intensities about one-tenth what they might be receiving outdoors.

There may have been some significant losses with age in the light output of some old T12 fluorescent lights, both in some deterioration of the phosphors in their tubes and deterioration of the analog electric ballasts driving them. But T8 tubes are modernized with improved phosphors and have ballasts with solid state digital circuitry driving them, so loss of light output with age is not a significant problem with my T8 lighting. The tubes themselves do need to be kept clean, and I use Bounty paper towels and Windex to keep my tubes reasonably clean. Over a period of time (months or years), some "stuff" does get onto the tubes.

" I suppose the whole idea, was about exposure to "red" light, but ultimately, for the plants, isn't it more about exposure to Ultraviolet light, from the sun? I know there is UVA & UVB , rays. "

I don't think that plants require ultra-violet light, although there is a significant amount of it in sunlight. I think that plants just require red and blue spectrum content. However, "I" require some green content, so I use white fluorescent tubes for pleasing "natural" light. Plants may like purple light, but I don't. So white light is what they get. Although, I do use different "flavors" of white -- warm white and cool white.

ZM

THose red lights in all the garden and box stores in Canada are because Canada legalized Marijuana and people are now allowed to grow 4 plants for their own use.
I would rather grow tomatoes ! But apparently red light is used to bring MJ plants to bud ?

SOme maroon and or red plants like BUlls Blood beets and purple basil probably might benefit from green lights.

" But apparently red light is used to bring MJ plants to bud ? "

That is probably the sales pitch. But plants all across the globe manage to come into bud in just plain sunlight. My zinnias do fine indoors in white light.

Clandestine marijuana growers who had grow rooms indoors, and sometimes underground, had to provide all the light artificially and their electric bill was a critical issue. So they could save money by just providing the absolute minimum of spectrum, consisting of just red light and blue light. Apparently blue supported the vegetative phase and red supported the flowering phase. But, in my opinion, home growers don't have to adhere to that red light thing.

ZM

CarolineScott said:SOme maroon and or red plants like BUlls Blood beets and purple basil probably might benefit from green lights.

I can see how you might think that, since "red" colored plants reflect red light and to our eyes not so much green, but that's not the case. Chlorophyll can't change its absorption spectrum according to what plant it is in. Plants may have a different ratio of chlorophyll A to chlorophyll B. (Each chlorophyll has a slight difference in light wavelengths that it uses.) But they still reflect predominantly green in the spectrum that we see. So green light is a poor source of energy for any plant that uses chlorophyll.

We all learned why leaves change color in the fall, and that at least some of that fall color is present all summer long in leaves, only masked by the overwhelming presence of the green chlorophyll. It's the same with "red" plants. The chlorophyll is still there doing its job, but masked by the overwhelming red.

THanks for the explanation, Rick.

Some of you may be interested in this podcast where they discuss this subject in more detail.
To listen or read:
https://joegardener.com/podcas...
It is an episode of the Joe Gardener Show with Joe Lamp'l of Growing a Greener World. This episode is called The Science of Light with Leslie Halleck, author of Gardening Under Lights.

Some seeds need light to germinate, others need darkness. Which color spectrum they need may vary from species to species. I use near red light to germinate my tomato seeds. Maybe y'all would like to hear what a scientist who has done research for NASA says on the subject of light spectrum and plant growth. I cannot post a link, so search youtube for Dr. Bruce Bugbee's video, Toward an Optimal Spectral Quality for Plant Growth and Development.