Grow Lights 24/7

[Nyboy]

Do trees sleep? I have a lemon tree going on my 2 winter. With the tempture dropping I moved it into my office.I have a grow light for it ,did same last winter, tree did great. After a break in I want to leave a light on at night. Can a tree or any plant, take light 24/7 or do they need dark for rest?

 

[pjn]

Do trees sleep? I have a lemon tree going on my 2 winter. With the tempture dropping I moved it into my office.I have a grow light for it ,did same last winter, tree did great. After a break in I want to leave a light on at night. Can a tree or any plant, take light 24/7 or do they need dark for rest?

I had security lights on 24/7 in my business and the plants did great. They were not trees, however some began to look like trees.

 

[baymule]

Not an expert here, but I do believe plants need some darkness.

 

[thistlebloom]

I'm not an expert either, but plants do need a period of darkness. They have found that trees growing near streetlights begin to develop certain problems. It takes several years to notice the problems, but it happens.

It has something to do with the type of lighting and the wavelength.
In ordinary outdoor conditions the stomata on the leaves close at night. With continuous light the stomata stay open.....and I'm not sure what that does, but that's about all I remember.

It probably isn't going to make a profound difference to your little lemon tree NYboy, so if it's more convenient for you to leave the light on it during the winter I sure wouldn't lose any sleep over it.

 

[Nyboy]

Would only be months that are cold. Late spring back outside.

 

[Smart Red]

Trying to rack my simple brain and remember what I taught for so many years. Plants make Chlorophyll during the day and give off oxygen, but they respire during the night and give off CO2 -- or something like that.

I usually have my light for seedlings on a timer so they get some night. I have an Aero-garden that has a built in timer so the light goes off for a while. Then again, there are plants growing in Malls that never close. They seem to be doing pretty well?

 

[PhilaGardener]

I think the gains go down as the electric bill goes up. That is to say that some plants are ok with 24/7 light but don't grow a whole lot more than if they had a 14 hour day. Of course, with a plant you may want to bloom and fruit, like that lemon tree, day/night length may be important.

 

[Nyboy]

Lemons are sun lovers, will report on tree all winter. Right now tree has about 10 unripe lemons and about 50 flowers.

 

[catjac1975]

In Alaska, where there is a short growing season, gardeners can get some good crops because of the period of months of 24 hour a day light. I start my seedlings under grow lights and leave them on 24 hours a day.

 

[baymule]

I bet that lemon tree smells so good!!!!

photosynthesis --- that's the work I was looking for and it finally popped out of somewhere in the dark twisted recesses of my tiny little mind!

http://en.wikipedia.org/wiki/Photosynthesis

Yes, plants do need darkness to grow.
First, in the photosynthesis process itself, there is a reaction known as 'dark reaction' pathway or lately known as 'carbon reaction' pathway where the free energy of ATP and reducing power of NADPH, are used to fix and reduce CO2 to form carbohydrate. This is very important process to release Oxygen into the air. This happened in the dark or at night.
Secondly, for inducing the plant to initiate flowering process. This phenomena is known as photoperiod, ie based on the ratio of the daylength to night length over 24 hours. Plants reaction to photoperiod can be divided into 4 groups.
a. Day-neutral plants - the plants has no effect on photoperiod, They will flower when the plant reach physiological maturity.
b. Short day plants - plants will only flowering when daylength is shorter than nightlength. This group of plants will only flower in late summer or fall or very early spring, when day length is shorter than the night period. e.g. strawberries, potatoes, chrysanthemums etc.
c. Long day plants - Plant that flower in spring or early summer. eg lettuce, spinach, radish etc. Flower initiation will begin when the daylength is getting longer than the dark period.
d. Intermediate day plants - These group of plants will grow vegetatively when daylength is either too long or too short. They will only flower when the day length is about 12hrs of daylight and 12 hrs of darkness.