How many hours of artificial light is too much?

14 years ago

I am growing about 8 plumeria plants and about 20 plumeria seedlings under florescent grow lights, twenty four hours a day. They are doing great, but someone said having them under lights 24 hours a day is not good. Has anyone else grown them under artificial lights 24 hours per day? If so, have you had any problems doing this?

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Comments (12)

karyn1
14 years ago
I keep the plants (not only plumies) that I'm wintering over under lights for 14-16 hours a day.
Dave in NoVA • N. Virginia • zone 7A
14 years ago
I have not grown them under lights 24/7, but I don't think there's anything wrong with it. In fact, you can root cuttings in winter by growing them under 24/7 lighting (plus heat). The only problem you might have is they will want to grow and the foliage will be prone to spider mites. If you can keep the temperature down to between 55 - 65Âº degrees you may have less of a problem with the mites. Also, I've had more mature plants bloom in winter under the long artificial light periods. For seedlings, I would probaby use light periods of between 14 and 18 hours.

I store plumerias all over the house, basement and garage. Some are under natural light and some under artificial. The ones under artificial did just fine, except for the mite problem, which is likely the result of the comb. of warm temps and light which contribute to soft growth. Misting and a fan to circulate air may be helpful. I've found that soft growth is more prone to burn from pesticides and oils.
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Well, here's an update. I followed the advice from the "Growing Under Lights" forum. Some one their recommended lights within 2" of the top of the plants and to run the lights for 16 hours each day. So, I set the timer, zipped up the plastic tent and went away. I did water once, a few weeks ago, and again today. Well, I now have a jungle of coleus plants. Several had grown up past the light, but those were mostly flower stalks that were probably started when i brought them inside. Some plants were already rooted, and some I rooted fresh at the time of my first post. Everything is thriving. I do have some gnats buzzing around, and I purchased a few of those sticky fly tape strips to hang inside the plastic covering to minimize their spread around the house. If my plants continue to grow this well, I could easily continue to take cuttings from the cuttings I already have, and end up with a hundred or more plants. And, under the artificial lights, the colors in the leaves are beautiful and rich. So, thanks for your help and advise. I'll try to keep in touch as the winter progresses. I'll also need to check my electricity bill. Adding another layer of lights would double the power needed to run my little hobby. I did take some cuttings from a coleus that a friend was tossing at the end of the season, and also some cuttings from my outdoor Persian Shield. As mentioned above, some people have success just keeping cuttings in plain water through the winter and planting them out in the spring. I may just try that. Though, I wonder if a longer winter has a greater chance of complications if plants are simply in water. My winters are pretty long, with first frost in early October and final frost or plant out date is June 1st. As the climate warms everywhere, those dates are less accurate, but we still have pretty cool night and soil temperatures for tropical plants. Best of luck to all. Martha
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meyermike_1micha
14 years ago
I thought that all plants had to have a certain amount of darkness, or at least cooling off at night to produce sugars to stay healthy.....This is quite intriguing...
What the heck is your electricity bill like with that much light..lol
I must say you love your plants..:-)
arctictropical
Original Author
14 years ago
Everyone..... thanks for your input. Maybe I'll leave the lights on for 18 hours and give them a 6 hour rest, and see what happens from there. One thing is for sure.... the plants that started going dormant are actively growing now, under the 24/7 light scenrio. So far spider mites is not an issue, but I have my pesticides ready, just in case.

Thanks again! Kevin
tropicalzone7
14 years ago
Sounds very good. It is definately true that plumerias can be forced to stay growing. I think that it is probably best for seedlings to stay actively growing during the winter so that way it gets large fast. Im sure everythng will work out well, and since they are under grow lights you can probably treat them just as you would when they are outside and give them lots of water, and maybe some plant food once a month.

Im still new to pluemrias and this is my first full winter that I will be over wintering them indoors. Dont forget to post how everything goes!

And if you do as good of a job with your plumies as you do with your palms, they will be blooming like crazy in no time!

Good luck!
Dave in NoVA • N. Virginia • zone 7A
14 years ago
Seedlings will definitely benefit from your lighting system. Many do not go dormant over winter and like to keep growing.
tdogdad
14 years ago
you can grow plants 24/7 but if you want healthy plants that flower well, you give them 6-10 hours of darkness so they can make sugars and expel oxygen.
arctictropical
Original Author
14 years ago
OK. Six hours of darkness they will get! Man, the heat from the florescent fixtures heats up this basement room to the point that it needs no heat from the furnace vents! It stays at about 78 - 80 F. during the day. If I add more fixtures, who knows how hot it will get.

Kevin
Dave in NoVA • N. Virginia • zone 7A
14 years ago
The lighting period question came up before. I think Mike actually brought it up. Jack (kimisdad) had some opinions about it.

Read old thread:

Here is a link that might be useful: Old thread
Dave in NoVA • N. Virginia • zone 7A
14 years ago
The lighting period question came up before. I think Mike actually brought it up. Jack (kimisdad) had some opinions about it.

Read old thread:

Here is a link that might be useful: Old thread
arctictropical
Original Author
14 years ago
A week ago I received two plants from a mail order company that were already dormant, with no leaves, and they were somewhat shriveled. Having them under the grow lights has already started bringing them out of dormancy. They've plumped up and are starting new leaves. Spring is here in the basement!
Dave in NoVA • N. Virginia • zone 7A
14 years ago
There is (or at least there used to be) a large Lei Rainbow plumeria plant here at the US Botanical Gardens (greenhouse) that never loses its leaves. The environment is warm and humid year-round. I think there is also supplemental lighting in the evenings.

How many hours of artificial light is too much?

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karyn1

Dave in NoVA • N. Virginia • zone 7A

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How many hours of artificial light is too much?

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