Lights on 24/7

[lilhammerlane]

Does it hurt to leave the lights on tomato seedlings around the clock?
Is there a such thing as, too much light?

[ArcherB]

I've heard that you should turn the light off at night to give the plants some "rest" time. However, I leave mine on 24/7 and my plants don't seem to mind.

[ContainerTed]

If you think about what the plants will be subjected to when they are planted outside, you'll know what to do. My lights go out for at least 7 hours per day.

Ted

[carolyn137]

There are two phases to the photosynthesis cycle, the light and the dark.

In the light cycle photosynthesis leads to the production of substances that will be incorporated into building the structures of the plants and also for fruit formation and maturation and also the energy compounds needed to do all that work.

In the dark phase what's been made by photosynthesis gets circulated around inside the plant to allow for growth of seedlings, which is your question.

So yes, as seedlings being grown inside, your question, they would do best with turning off the lights at night. Many folks use a timer(s) to do that. I just turned the lights on when I got up and turned them off when I went to bed.

[Fusion_power]

I've done this both ways and can give some answers. Some plants are severely suppressed by 24/7 light. Tomatoes are NOT one of them. However, tomatoes don't grow quite as fast under 24/7 lights and you run the risk of leaf damage if you have the plants too close to the bulbs. With that said, I've pushed peppers with 24/7 lights very successfully until the last 2 weeks before they are sold at which time I put them in the greenhouse under natural sunlight until they are acclimated.

My overall recommendation would be 16 hours of light with 8 hours of dark to get the best growth from tomatoes.

DarJones

[BigBrownDogHouse]

Originally Posted by carolyn137

I just turned the lights on when I got up and turned them off when I went to bed.

Yup, me too!
I just make it a part of my routine. Wake up, make the coffee, turn on the tomato lights...........let out the dogs one last time, double check the doors, turn off the tomato lights.

[carolyn137]

Darrel, it's true that tomatoes are not severly depressed by 24/7 lights but they are affected by 24 hr light and I think it's much better as you've also agreed, to shut off the lights at night.

And it also depends on what kind of lights are being used as to broad spectrum high cost bulbs or just warm and a cool shoplight bulbs in a single fixture. I started out with the former and found essentially no difference with the latter and so much less expensive and available everywhere.

[carolyn137]

http://www.tomatoville.com/showthrea...150#post198150

I just discovered this thread in the starting From Seed forum which is all about lights and starting from seed. So those of you reading here may want to read there as well. I didn't many posts there so I don't know how much overlap there is.

[roper2008]

I always turn mine off when I go to bed and turn them back on when I
wake up. Mother Nature has darkness for all plants, so I figure I'll do the
same with mine.

[Chucker]

I ran my lights 24/7 last year and am doing it again this year.

I started doing it after reading this post:
http://forums.gardenweb.com/forums/l...125925834.html

The pictures of the peppers were pretty convincing. Somewhere, he said he had the same results with tomatoes. Also, if you read the whole thread there is evidence that 24/7 is a bad thing, so it's worth keeping in mind that it might not be a good idea.

My plants seem happy and it's easier. Plus I've read that florescent bulbs last longer when left on all the time.

[casino]

I have a question about lights. When I start my tomatoes indoors under florescent shop lights I run the bulbs for 16 hours a day for one month and then I dont use them again until next year to start my matters. Question, How long do you think I can use those shop lights (one cool & one warm) lights before they need to be replaced or should I buy fresh lights every year?

[fortyonenorth]

I believe tubes are rated at 15,000-20,000 hours. If you're only using them for a month, that works out to about 500 hours per year. That means you should change them every 30 years - whether you need to or not

That seems like a long time. I'd just run them until they die or until they begin to buzz or flicker. Otherwise, I think you're o.k.

Originally Posted by casino

I have a question about lights. When I start my tomatoes indoors under florescent shop lights I run the bulbs for 16 hours a day for one month and then I dont use them again until next year to start my matters. Question, How long do you think I can use those shop lights (one cool & one warm) lights before they need to be replaced or should I buy fresh lights every year?

[Fusion_power]

Fluorescent bulbs get dimmer with age, they distinctly lose their pizazz. I suggest replacing bulbs after about 3 or 4 years of use given that they are used 1 to 2 months each year for plants.

DarJones

[dice]

The light output decay with time curve for flourescent bulbs
in hours can be found in a graph in this document:
http://www.gel.net.au/howitworks.htm

(I have not used the product described, and most flourescent
fixtures sold at retail in the US are wired for 120v rather than
240v, anyway. The graph is still useful, though.)

[fortyonenorth]

Good feedback guys - thanks for posting this.