Interesting result with light cycle change.

I've always grown anything under a light with 24/0. I figured that the more light, the better and I've read articles that argue that it matters not. I've had some kind of Thai peppers (dont know the exact type because they were brought back from Thailand by the neighbor from a trip), some basil, and one bhut jolokia that has been the saddest looking yet most resilient plant I've had ever. (The bhut was a stick after a cold snap killed all the leaves on it, I brought the stick indoors in the planter and with some artificial light and warmth, it began to spring up all kidns of leaves).

Anyway. I had them under 24/0 110w cfl (2g11 base 6400k bulbs) and they stayed alive, but I also have an infestation of thrips and can only "manage" the pests. The bugs are causing some damage but there arent that many of them (and I know, if you see 5, you have 500). In prep for more plants to get my garden stuff going to go outdoors, I bought a powerful lumigrow es330 and thought the philosophy - More Light, outgrow the problems. I put that on a 24/0 cycle too. I figured if I can get them along until its warm enough to go outside, nature will take care of my thrip problem. I'm sure there is plenty of control in spiders and other predators that will help. I played with different light settings, but always kept the constant on.

For the past 3 weeks, it was the same. A little foliage, couple leaves drop, see a few thrips and the silvery markings of their damage and the plants never got any size. I kept clipping the basil but it seems a little overwatered.

Just 2 days ago, I put it on a timer at 18/6 as an experiment because I thought the plants were just going to stay "meh" but in the last 3 cycles, I've had the plants completely change. They produced new growth immediately, leaves opened up, and they started to gain a coule cm of height. Its also been a little hotter here with the weather and the space went from the 77f to about 85f at the peak. I have a small germination tent that use like an infirmary for getting plants back to health. Its definitely amazing. I'll have to post some before/after pics (I dont have a pic host like photobucket account).

So, experiment with your light cycles. Perhaps these suckers need a little dark to rest. I've always heard that plants "sleep" and repair root systems, but I guess its part of the nature's plan. I never thought the reaction woud be a so immediate.

MHz

In a nutshell, I've understood that light provides energy for growth (photosynthesis?) and most of the actual growth itself occurs during nighttime...I'm not a scientist, so please don't yell at me! lol!

Yea, i use 16-18 hours of light inside. FOr some reason, i had thought i heard, or read somewhere that plants doing there growing in the dark cycle. NOt sure how true that is, but I always give them a good 6 hours of dark to recope from a long day of work.

I suppose it's kinda like our bodies - exercise during the day and rebuild and grow while we sleep...

yeah its true, I was doing the 18/6 hour cycle at first with my first batch and they grew great and really fast, and then this new batch I figured I would leave them on all the time, and then when they were turning too purple, I switched to 20/4 and they got better but didn't grow as well still.. so I went back to the 18/6 and they are starting to do much better overall..

the plants grow when it's dark which is when they respire aerobically where they use the oxygen when they open their pores at night and use it to break down the sugars and bla bla bla.. but basically they grow.. the daytime, as far as I remember from classes is mainly, if not exclusively for collecting ATP/energy via photosynthesis and all that good stuff...

so it seems that it needs a good 6 hours for them to utilize all the energy they have obtained from the daylight cycle, where as 4 or nothing just doesn't cut it, and yeah that's funny because our bodies need about 5 hours of sleep to get into the first REM cycle (about/on average). .I guess that is a semi-common evolutionarily trait for "rest time".. pretty interesting stuff

I'll have to look up some more info on this but that's just what I remember from the earlier bio classes I took.. after that it's just been boring micro and chem... stuff sucks lol

This illustration explains the Calvin cycle (dark cycle) pretty well:

Interesting....this also reminds me of my digestive tract's reaction to eating bhut jolokia.

I'm guessing the export would be pain, instead of sucrose and o2 though haha

^^ lol

and here is another article I found interesting and is a nice simplified review I think

I thought the temp. statement towards the end was the best.. where photosynthesis is at it's highest rate between 65-85 degrees, and decreases once it goes out of that range.. I guess I won't have to worry about my heater going for much longer, I can keep it at 65, but I am going to wait a little longer until it gets warmer out, and until the plants i just potted up get a little bigger before shutting it off.. fun stuff
http://ag.arizona.ed...physiology.html

Edit: I've been reading about light cycles because I found one that I think suggested that a 24 on 24 off cycle was really beneficial.. but I couldn't find much more on that yet.. but I found this article when looking to try to find out which type of plant a pepper plant is in terms of a "long day plants", "short" or "medium" day plants.. it was more specific to flowering.. but an over all review was that it seems that the pepper plants produced the most flowers in the "normal day" which looking for it, is really annoying because they don't say how long that actually is, but it was in the middle of winter so somewhere it seems around 10 or maybe a little more hours of light.... BUT they also said that actual "growth" which they attributed to just the availability of starches was directly proportional to the amount of light, meaning that more light is more growth.. (and based on the other articles I was reading, it only goes up to a certain point, and 16-18 hours seems to be around that amount, for overall growth.. unless I can find more info on the 24 on 24 off cycles.. but no luck so far)
http://www.jstor.org/stable/2435497 (might not be able to see it, and it is annoying that i can't get the whole article without paying for it.. but $10 is crazy just for one article.)

so just thought I would add that in there.. next year during the winter, I will have to do some experiments with the plants that I plan to overwinter.. I plan to keep them large and not cut them back for the fall, until around Dec. or so when I start my other seeds, then I will cut them back a bit so I can have more room in the tent for when the next batch of baby plants are ready.. should be fun

Freaking Calvin dude has a light cycle? I want one.

What size plants are we talking about? I've always thought for the best growth of seedlings you had the lights on 24/7. Some of them will start leaning a bit after a few hours of no light.

Great information by the way.

meinchoh said:

In a nutshell, I've understood that light provides energy for growth (photosynthesis?) and most of the actual growth itself occurs during nighttime...I'm not a scientist, so please don't yell at me! lol!

Click to expand...

I have noticed this often in my gardening experience. Almost always,
new growth pushes out farthest at night. I always look for changes in
my plants in the morning, before it warms up, when plants are outside.
In general we can answer most of our own questions with careful
observation, we just have to learn to trust our instincts! (Nod to AJ)

patrick said:

What size plants are we talking about? I've always thought for the best growth of seedlings you had the lights on 24/7. Some of them will start leaning a bit after a few hours of no light.

Click to expand...

I think this is true after the plants put on true leaves and they can
then start photosynthesis.

There was some swedish guy who set up a camera on his chilipepper plant from seed to harvest.

There you could see at night the plant grew and at day it dident do much more then leaning at the light.

I think 16h of light is good. I think i run mine at 18h atm but i will soon put it down to 16 i got lots of big leafs but not much hight

24/7 prob works the first week or two.

My 5 cents am not an expert but since i saw that cam video i figured they grew while they "rested" at night.

Here's a popular article around here

""Optimal growth and yields of tomato and sweet pepper were obtained under photoperiods of 14 and 20 hours, respectively. Longer photoperiods did not further improve growth and yields and even decreased growth and yields in some cases. Although long term use of continuous light is detrimental to tomato and pepper plants, vegetative growth and fruit production of both species can be improved by short term use (5 to 7 weeks) of continuous lighting. Compared to shorter photoperiods, continuous light (24-h photoperiod) increased the leaf levels of hexoses in tomato, of sucrose in pepper and of starch in both species. The accumulation of starch and sugar in leaves under continuous light indicate a limitation of tomato and pepper plants to export the photosynthate out of their leaves. Such a limitation would explain the fact that extra light energy provided by continuous lighting did not result into growth and yield gains"
http://www.actahort.org/books/580/580_9.htm

patrick said:

Freaking Calvin dude has a light cycle? I want one.

What size plants are we talking about? I've always thought for the best growth of seedlings you had the lights on 24/7. Some of them will start leaning a bit after a few hours of no light.

Great information by the way.

Click to expand...

lol, it must have been a ton of work to figure that stuff out first. I would be mad if I didn't get to name something like that after myself, that's how most things are in science.. at least processes and stuff, not so much actual names of organisms

but yeah, I think it's like what PaulG said, after they have their set of true leaves.. I personally just noticed that on 24/7 they were starting to turn purple, which is fine, but I wouldn't mind saving some energy and no need to stress them out too much with more light than they need, so I just dropped it down to 18-6, but that's just me personally, and I am just trying to get these thing to grow now rather than being able to experiment and test different methods yet lol.. next year though

PaulG said:

I have noticed this often in my gardening experience. Almost always,
new growth pushes out farthest at night. I always look for changes in
my plants in the morning, before it warms up, when plants are outside.
In general we can answer most of our own questions with careful
observation, we just have to learn to trust our instincts! (Nod to AJ)



I think this is true after the plants put on true leaves and they can
then start photosynthesis.

Click to expand...

yup, it's pretty funny what you "already know" if you just pay attention.. it's fun to figure out what else is possible with some research, I never really cared to much for plants but I want to try to find more info about the light cycles, I added some more stuff on my last post, but that was just for flowering.. and stuff, would be interesting to find something else about it, next year should be fun to be able to experiment more with the cycles, but this year I am just trying to figure everything out

I'm with you, Max! Find something that works and do it!

Just wanted to say I was running 24/7 for a while and switched over to 18/6 just yesterday after reading this thread. I can see RESULTS already. Thanks for sharing the info. I was curious about the light cycles and it's nice to find all these resources in one place.

Yep I turned my lights off last night for the very first time. Can't say I noticed any change though. Time to invest in another cheap timer.

Wow, so I left this post here of mine in the dark, and I'm amazed at how much the thread has grown...lol.

I would say that the timer is better than manual intervention. I have had them on the timer for a week now, and the growth rate surprises me. It seems that they'll outgrow those pesky thrips after all. I guess by March, it will be warm enough to keep outside. Its still dipping to the 40's here and we could still get a frost. I've got my tray and new pepers are starting, plus I just got a new batch of pepper seeds to try.

MHz

POTAWIE said:

Here's a popular article around here

""Optimal growth and yields of tomato and sweet pepper were obtained under photoperiods of 14 and 20 hours, respectively. Longer photoperiods did not further improve growth and yields and even decreased growth and yields in some cases. Although long term use of continuous light is detrimental to tomato and pepper plants, vegetative growth and fruit production of both species can be improved by short term use (5 to 7 weeks) of continuous lighting. Compared to shorter photoperiods, continuous light (24-h photoperiod) increased the leaf levels of hexoses in tomato, of sucrose in pepper and of starch in both species. The accumulation of starch and sugar in leaves under continuous light indicate a limitation of tomato and pepper plants to export the photosynthate out of their leaves. Such a limitation would explain the fact that extra light energy provided by continuous lighting did not result into growth and yield gains"
http://www.actahort....s/580/580_9.htm

Click to expand...

Does anyone have a copy of this article? I'd love to read the whole thing.

EDIT: I FOUND IT!

The Calvin cycle goes on 24 hours a day, not JUST at night. However the plants tend to open many more stoma at night, especially plants that favor drier environments such as chili peppers, so photosynthesis can perform at its peak in the mornings when the plant has a ready supply of CO2.

24 hour light for seedlings will not hurt them much (if at all) and it has been considered to be beneficial by some. I haven't really read up on that aspect of it. I think once you have 2-3 pairs of true leaves you should switch to 18/6 (or even 20/4) for the best possible growth rate.