Growth during the night

[southpaw]

Neat article here for anyone interested. I've wondered for awhile why plants seem to get noticeably taller during the dark hours. I keep my fluoros about as close as possible to the canopy during the day, and when the plants are healthy, I almost always have to raise the lights before they go on in the morning. Turns out it wasn't just my imagination messing with me.

http://www.universityofcalifornia.edu/news/article/18527

This also gives another dimension to why foliar feeding, especially a mix with a hormone or growth inducing profile including kelp or alfalfa, gains an extra boost when done in the morning or early evening.

But I'm still curious about one detail. If the genetic triggers they describe are associated with light levels at dawn and dusk, how is it our indoor plants exhibit the same behavior without any real gradual changes in light levels? I guess HIDs do this to a very minimal degree while they heat up, but definitely not fluorescents, and even then it's nothing like a true sunrise/ sunset. Any ideas?

I wish I had more time to read up on plant science, man is it some cool stuff. You professional biologists are very lucky people.

 

[OrganicMonkey]

I have read that plants do work at night, they don't go dormant. This explains that when a plant stretches in veg, when their lateral shoots start to grow is caused by hormone levels in these lateral shoots being to low.

I don't think sun rise and sun set says much to the plant, other then what the weather for the day or night is going to be. I don't see why they wouldn't be sensitive to atmospheric pressure either.

These hormone changes, don't matter as much as they fluctuate outdoors. Indoors, it's very consistent so it's not inhibiting anything other then flowering or veg. There just really isn't much to say about it, these biology articles come from people that must publish to make money!

 

[Guywithoutajeep]

There just really isn't much to say about it, these biology articles come from people that must publish to make money!

nice comment about the biologists, how rude...

Great link dude. I would love to read the actual studies. I'll be going through a molecular genetics course and can not wait to get to my independant research section. One of the most puzzling things is how genetics play into the seasons and the plants biological clock. I've wanted to tackle this for a long time because I believe the answer to hemaphroditism lies here. They're getting very to close to centering in on those biological clock genes.

 

[mrred]

you can use a short night cycle to keep the plants shorter

 

[HIGHGROOVE]

so then are you not suggesting 24 hours light for veg?

 

[southpaw]

Organicmonkey... Heh, what's the saying, publish or die? My background is in the humanities, so I've read plenty of "studies" that seem worth less than Wonderbread, but this doesn't seem like one of those.

Guywithoutajeep... The whole topic seems extremely fertile for research. If I had it to do all over again, molecular and cell biology is what I would study. There is SO much we still don't know about plant life.

mrred... Depending on personal experience and the stock you put in the theory in this article, that certainly seems possible. I'm running 17/7 now to nudge some really prudish indicas into showing sex, that might be why I'm seeing the amount of night growth I'm seeing.

HIGHGROOVE... I definitely didn't mean to start another 24/0 vs. 18/6 war, if you are doing well with 24/0, by all means stick with it. I personally run either 20/4 or less when growing from seed, it saves on bulbs, and even plants under constant light go through a daily cycle, you can see the leaves still rising and falling. This article seems to suggest that constant light might be inhibiting certain processes to some degree, but too many people do it for me to think it's drastically "unhealthy". It also pretty much can't be beat for revegging.

 

[Tony Aroma]

Of course plants grow in the dark. They continue to respire, like we do, they just don't photosynthesize without light. That's why low light causes plants to stretch -- the less light, the faster they grow. That's also why plants turn toward the light -- because they grow a bit faster on the side facing away from the light.

 

[big ballin 88]

I agree with this. I noticed on my tomatoes plants that were under a regular light schedule of day and night grew taller and quicker than the same plants under 24hrs of light. I think it proves little,but to me plants are naturally used to time periods and depending upon their locations are very different. Unless the plant is growing in the N/S Pole is about the only time i can imagine it getting 24hrs of light. Besides that i think that plants use this period to stretch their roots since plants switch from taking in CO2 to oxygen at night. In my mind since the roots use oxygen that may be a reason the roots stretch during night.

Also the reason they go towards the light is called phototropism, and plants will direct themselves in the best position to capture light. Plants dont gro stronger under low light either their stem remains very skinny as they reach to get enough potential light to continue further growth. Not all growth is about vertical movement.

Southpaw- I'm going to try and use 17/7 to see if it helps my plants show sex, i dont have the space to switch yet and really would like to see some preflowers. I really dont want to take clones yet.