FlytrapCare Carnivorous Plant Forums

Anyone know whether does plant need a dark time to rest?

All plants need some darkness, but I wouldn't call it a rest. Some of plant's biological processes occur during the night when there is no light to carry on with photosynthesis. I found these couple of paragraphs on a website that might explain it in layman's terms better than I can, haha...

"A: Interesting issue. You're right in that most plants perform best when they have alternating periods of light and darkness. After all, that's what they're used to in nature! Some plants absolutely demand particular light periods or else they won't fruit or flower. The poinsettia is the best known example of a plant that uses light/dark periods to gauge when it's time to color up.
Plants take advantage of dark times to ramp up the manufacture of plant sugars that their roots store for use in making new cells for growth. It's kind of like a factory where the raw materials are being unloaded all day (i.e. water from the soil, light from above and carbon dioxide from the air), and then when the 'trucks' leave, the workers have time to actually produce the goods."

I personally think they need a break from light. It helps them understand what time of year it is and helps regulate their own biological clock,

Yes, all plants need a daily period of light and dark because that's what they've evolved to grow with in nature. The length and intensity of the daylight period does vary over the seasons throughout the year though. When I bring my plants inside during the fall, I try to keep the timer on my artificial lights in sync with the number of hours of daylight that are occurring outdoors. That way, the photo-period is the same as what they would be receiving outdoors, but they're protected from the sub-freezing temp's that would kill them.

Well, my CPs have been under my light for 24/7 for 2months already. I shall go and off it now before any bad things happen.

For the most part plants do need a dark time for part of their cellular processes.

Though I should add that people do an accelerated growth on sarracenia seedlings where they put them under 24 hour light for the first couple years without problems.

Anything other than that I would try not to go over a 16-18 hour photo period.

As parker said, i keep my sarracenia seedlings under a 24 hour light photoperiod for the first year, then i accumulate them to lesser light, then move them outside. But i have tried some venus flytraps and droseras under 24 hour light photoperiod. They did ok, but not any advanced growth, or damadged the plant. Their seemed to be no change to them.,

Many plants will simply remain in suspended animation under a constant light source, due to the fact that many plants need to stop pfotosynthesizing to be able to use the gulcose they stored up while photosynthesizing.

If you want to know a bit of biology behind it, photosynthesis takes energy in the form of light, and stores it in the bonds of a sugar called glucose. A process called cellular respiration is the opposite of photosynthesis, so it takes glucose and breaks the bonds to release energy.
When exposed to light, plants preform photosynthesis, as attested to the fact that oxygen is released.
When not exposed to light, plants begin to preform cellular respiration to release the energy necessary for many tasks within the cell. This can be proven by the fact that plants release carbon dioxide in the dark, just like animals do all the time.

Unless cellular respiration occurs, cell division cannot physically happen. Therefore, a plant under a constant light source will never be able to grow, unless it can preform cellular respiration and photosynthesis in large amounts at the same time, which does not occur in most plants.

beckhamlim24 wrote:Well, my CPs have been under my light for 24/7 for 2months already. I shall go and off it now before any bad things happen.

Do tell us if something bad happens when you put your plants to normal rest, because you keept them so long 24 hours.

bananaman wrote:Unless cellular respiration occurs, cell division cannot physically happen. Therefore, a plant under a constant light source will never be able to grow, unless it can preform cellular respiration and photosynthesis in large amounts at the same time, which does not occur in most plants.

While I understand the theory of this, it's clearly not the case universally. If it was than people wouldn't be able to put Sarr's under 24/7 lights and produce adult flowering sized plants in 1-2 years less time than "naturally" grown plants.

This post has some pictures of plants that were claimed to have been under 24/7 lights and fertilized regularly.

I'm not saying all plants should be grown this way. Or even that Sarrs older than a couple years should be grown this way. But it's clear that there is significant growth from some plants kept under lights 24/7.