Plant Growth at Night

AlittleSalt · August 25, 2015

I've noticed that tomato plants grow a lot more overnight this year. I haven't read-up on this yet, but I started noticing that the tomato plants still in their seed cells grew much faster overnight when the lights were out. I noticed this happening even more when the tomato plants were transplanted into their solo cups. I could understand this easier if it were due to moon cycles or something like that, but there's no moon inside our house where the seed trays and solo cups were located.

Then there is what I've noticed after I planted them in-ground. It seems the tomato plants stay the same size during the day, but when I go out to check them the next morning - the plant has grown. It's easy to track their growth while growing in cages. I've also noticed that pepper plants grow more overnight as well.

I would like to know your thoughts and opinions about this.

RayR · August 25, 2015

That's what plant do. The energy they collect during the day from photosynthesis is converted into growth at night.

Worth1 · August 25, 2015

Many plants do this including beans.
That is why when growing inside with lights it is best to give them a 16 hour on and an 8 hour off light cycle.
I try to have the lights on during the day so it is dark in the room at night.

Worth

Fusion_power · August 25, 2015

Most tomatoes are sensitive to light such that if you put them in 24/7 artificial lights, they will either exhibit severely suppressed growth or in some cases die. Recent research identified some genes that allow a plant to thrive under 24 hour lights. Google can find the research if you want to read it.

Starlight · August 25, 2015

I know some folks won't agree with my method of growing, but here goes. Usually I am starting tomato and pepper seed in the house in Jan and Feb. I keep them going under lights. It's many weeks and months before they can go outside to even start being hardened off. Too keep from having tall stringy plants, and having to do a lot of transplanting and no room for bigger containers, as soon as the seeds sprout I put them under the lights and they will stay under those lights 24/7 for weeks and weeks.

I do that will all my seed whether it is veggie or flower. While the tops don't stretch and grow very much the roots still do. That way I can keep hundreds of seedlings going in a small space. The plants still do grow and I have to raise the lights. I just do it at a slower rate.

When the plants start getting several sets of true leaves and I can't raise the lights up anymore, than I will transplant them a few days before I plan to start hardening them off, then that is when I will start turning off lights at night for them to start foliage growth.

Unless I have a seed, few are this way, that need total darkness to germinate, I plant my seeds and they stay under the lights 24/7 for germination too. This wasn't a method I just stumbled upon or read, it was one taught to me by my mentor.

I've been starting and growing seed that way for years and years and never had a problem. It works for me.

But yes, the plants collect from the sun, water, co2, and store it during the day, convert it into sugars and then use it during the night. There are alot of interesting reads about how those plants have down to a science of how much sugar for growth they can use at night so they don't die like Fusion said if they use it all up.

Lorri D · August 25, 2015

I've done it both ways with professional grow lights and I've noticed little difference. I only grow to the transplant stage, so perhaps that is why there is not much difference that shows in my plants. My only goal is to not have leggy plants. I keep a fan on them for half a day too. I get really strong, stocky, green plants this way. But, I don't recommend this, unless you are able to check on their water. I worked from home and now I go to school, so I can be here and make sure they aren't drying out.

For convenience and for $$ and so my neighbors don't think I am growing pot, I turn them on when I get up around 4am and turn them off when I go to bed around 9-10pm.

What you want to do is read up on c3, c4, and cam plants. And, DIF...greenhouse/propagation technique.

Gardeneer · August 25, 2015

Most plants have day/night program. Flowers mostly open at night.
To me. best you can do is mimic the nature/climate that a given plant belongs to.
Nowher on the Erarth plants get 24 hours of light.
JMO

Gardeneer

AlittleSalt · August 26, 2015

Gardeneer, I was thinking somewhere along the same lines: About following or mimicking nature here in zone 8A Texas. I am thinking that the best time to feed/fertilize plants may be late evening just before the plants have already proven to grow.

Maybe cultivating some fertilizer right before drip irrigation in late evening would feed the plants when they need and want it most? A thought to try for me.

Starlight · August 26, 2015

Quote:

Originally Posted by Gardeneer

Most plants have day/night program. Flowers mostly open at night.
To me. best you can do is mimic the nature/climate that a given plant belongs to.
Nowher on the Erarth plants get 24 hours of light.
JMO

Gardeneer

True. But just for the heck of it, if your able try it some time. Leave a couple of seedlings under lights 24/7 and see what happens and the difference between an on and off lighted plant and an all light one. Once outside, they go back to the natural rhythm of nature.

Salt... when do you normally do your watering? I do all mine usually around 6 pm. Sun is off the plants and they have had a chance to cool down and the water than has a chance to soak into the soil and feed the plants.

Worth1 · August 26, 2015

Quote:

Originally Posted by Gardeneer

Most plants have day/night program. Flowers mostly open at night.
To me. best you can do is mimic the nature/climate that a given plant belongs to.
Nowher on the Erarth plants get 24 hours of light.
JMO

Gardeneer

Nowhere on earth do plants get 24 hours of light.

How about anything above the arctic circle.

The sun stays up all day and night on the north coast of Alaska and many other places.
I have yet to see a wild tomato plant there though.

Worth

JLJ_ · August 26, 2015

I have timers on my lights for plant starting and have used timed light/dark seed starting, but I have the best luck with 24/7 light on them.

Emulating nature for best plant welfare is always a good thought -- but something else that has to be considered is that there are many ways besides hours of light in which indoor starting varies from outdoor growing. For one example, while outdoor plants in most areas have less than 24 hours of light, they get it from a source that is a whole heap brighter than grow lights and which produces light of different composition.

Lorri D · August 26, 2015

The only problem with mimicking nature, which granted is usually is the correct thing to do... is that you are not going to get the full strength of sunlight by using artificial light. No artificial light comes close to sunlight.

I often think about Alaska and the huge garden plants that are grown there during their long days. I always wonder if it is the light or the soil. I believe both, since I've heard it argued both ways very well. Maine, USA... is a huge grower of tomatoes in winter, because they grow on the tops of mountains above the clouds in glass greenhouses that get the most out of natural sunlight.

It all comes down to photosynthesis and respiration (respiration, not to be confused with transpiration) and if the plant is doing too much respiration, it won't be growing much.

as far as economical.... one of the most economical ways to regulate plant growth is through DIF.

Fusion_power · August 26, 2015

Quote:

I have yet to see a wild tomato plant there though.

and you have been spending a few weeks on Alaska's north shore fishing.... Right?

Quote:

No artificial light comes close to sunlight.

Most lighting systems are based on providing about 25% as much light as full sunlight. C3 photosynthesis saturates about this level. Providing more light than saturation just wastes energy.

trivia - full sunlight is about 2000 mols depending on where you are near sea level or high on a mountain where there is less air to absorb light. C3 photosynthesis saturates around 500 mols. Healthy seedlings can be produced with as little as 200 mols if other conditions are favorable.

If you want to try a regime that produces more growth than 24 hour light, try 20 hours light and 4 hours dark. See what happens.

AlittleSalt · August 26, 2015

Quote:

Originally Posted by Fusion_power

If you want to try a regime that produces more growth than 24 hour light, try 20 hours light and 4 hours dark. See what happens.

This gives me food for thought. We could try this in my wife's sewing building. It is fully insulated, has windows, and is easily heated. I've been thinking of growing smaller tomato plants through the winter - now I have a reason/excuse. I'll have to get a timer for the lights.

I'll talk to my wife more about it tomorrow night after our grandchildren are taken home. Besides, I'm curious now.

Lorri D · August 27, 2015

Quote:

Originally Posted by Fusion_power

and you have been spending a few weeks on Alaska's north shore fishing.... Right?

Most lighting systems are based on providing about 25% as much light as full sunlight. C3 photosynthesis saturates about this level. Providing more light than saturation just wastes energy.

trivia - full sunlight is about 2000 mols depending on where you are near sea level or high on a mountain where there is less air to absorb light. C3 photosynthesis saturates around 500 mols. Healthy seedlings can be produced with as little as 200 mols if other conditions are favorable.

If you want to try a regime that produces more growth than 24 hour light, try 20 hours light and 4 hours dark. See what happens.

Lol, well you got me at mols, it sounds like you are way over my head. I've only been taught foot candles and the color temperature scale and inverse-square law of light. It is pounded into us that no lights will ever be as good as sunlight, because of the foot candles it produces and it provides the full color temperature range. We also learned that there were different types of chlorophyll and that they perform optimally at slightly different levels of color temperature.

I am good with what I am doing. I've done lots of experimentation and reading. I think I am getting the best seedlings I can with the lights I have and I have to pat myself on the back, because they look better than most nurseries. Talk, experiment, and learn.... I love learning about new things from you all.

August 25, 2015	#1
AlittleSalt BANNED FOR LIFE Join Date: May 2014 Posts: 13,333	Plant Growth at Night I've noticed that tomato plants grow a lot more overnight this year. I haven't read-up on this yet, but I started noticing that the tomato plants still in their seed cells grew much faster overnight when the lights were out. I noticed this happening even more when the tomato plants were transplanted into their solo cups. I could understand this easier if it were due to moon cycles or something like that, but there's no moon inside our house where the seed trays and solo cups were located. Then there is what I've noticed after I planted them in-ground. It seems the tomato plants stay the same size during the day, but when I go out to check them the next morning - the plant has grown. It's easy to track their growth while growing in cages. I've also noticed that pepper plants grow more overnight as well. I would like to know your thoughts and opinions about this.

August 25, 2015	#6
Lorri D Tomatovillian™ Join Date: Jan 2012 Location: NorthWest Posts: 267	I've done it both ways with professional grow lights and I've noticed little difference. I only grow to the transplant stage, so perhaps that is why there is not much difference that shows in my plants. My only goal is to not have leggy plants. I keep a fan on them for half a day too. I get really strong, stocky, green plants this way. But, I don't recommend this, unless you are able to check on their water. I worked from home and now I go to school, so I can be here and make sure they aren't drying out. For convenience and for $$ and so my neighbors don't think I am growing pot, I turn them on when I get up around 4am and turn them off when I go to bed around 9-10pm. What you want to do is read up on c3, c4, and cam plants. And, DIF...greenhouse/propagation technique. Last edited by Lorri D; August 25, 2015 at 07:59 PM.

August 26, 2015	#12
Lorri D Tomatovillian™ Join Date: Jan 2012 Location: NorthWest Posts: 267	The only problem with mimicking nature, which granted is usually is the correct thing to do... is that you are not going to get the full strength of sunlight by using artificial light. No artificial light comes close to sunlight. I often think about Alaska and the huge garden plants that are grown there during their long days. I always wonder if it is the light or the soil. I believe both, since I've heard it argued both ways very well. Maine, USA... is a huge grower of tomatoes in winter, because they grow on the tops of mountains above the clouds in glass greenhouses that get the most out of natural sunlight. It all comes down to photosynthesis and respiration (respiration, not to be confused with transpiration) and if the plant is doing too much respiration, it won't be growing much. as far as economical.... one of the most economical ways to regulate plant growth is through DIF. Last edited by Lorri D; August 26, 2015 at 02:23 PM.

August 25, 2015	#2
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	That's what plant do. The energy they collect during the day from photosynthesis is converted into growth at night.

August 25, 2015	#3
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	Many plants do this including beans. That is why when growing inside with lights it is best to give them a 16 hour on and an 8 hour off light cycle. I try to have the lights on during the day so it is dark in the room at night. Worth

August 25, 2015	#4
Fusion_power Tomatovillian™ Join Date: Feb 2006 Location: Alabama Posts: 2,250	Most tomatoes are sensitive to light such that if you put them in 24/7 artificial lights, they will either exhibit severely suppressed growth or in some cases die. Recent research identified some genes that allow a plant to thrive under 24 hour lights. Google can find the research if you want to read it.

August 25, 2015	#5
Starlight Tomatovillian™ Join Date: Jan 2015 Location: AL Posts: 1,993	I know some folks won't agree with my method of growing, but here goes. Usually I am starting tomato and pepper seed in the house in Jan and Feb. I keep them going under lights. It's many weeks and months before they can go outside to even start being hardened off. Too keep from having tall stringy plants, and having to do a lot of transplanting and no room for bigger containers, as soon as the seeds sprout I put them under the lights and they will stay under those lights 24/7 for weeks and weeks. I do that will all my seed whether it is veggie or flower. While the tops don't stretch and grow very much the roots still do. That way I can keep hundreds of seedlings going in a small space. The plants still do grow and I have to raise the lights. I just do it at a slower rate. When the plants start getting several sets of true leaves and I can't raise the lights up anymore, than I will transplant them a few days before I plan to start hardening them off, then that is when I will start turning off lights at night for them to start foliage growth. Unless I have a seed, few are this way, that need total darkness to germinate, I plant my seeds and they stay under the lights 24/7 for germination too. This wasn't a method I just stumbled upon or read, it was one taught to me by my mentor. I've been starting and growing seed that way for years and years and never had a problem. It works for me. But yes, the plants collect from the sun, water, co2, and store it during the day, convert it into sugars and then use it during the night. There are alot of interesting reads about how those plants have down to a science of how much sugar for growth they can use at night so they don't die like Fusion said if they use it all up.

August 25, 2015	#7
Gardeneer Tomatovillian™ Join Date: Feb 2015 Location: NC - zone 8a - heat zone 7 Posts: 4,919	Most plants have day/night program. Flowers mostly open at night. To me. best you can do is mimic the nature/climate that a given plant belongs to. Nowher on the Erarth plants get 24 hours of light. JMO Gardeneer

August 26, 2015	#11
JLJ_ Tomatovillian™ Join Date: Aug 2011 Location: Wyoming Posts: 759	I have timers on my lights for plant starting and have used timed light/dark seed starting, but I have the best luck with 24/7 light on them. Emulating nature for best plant welfare is always a good thought -- but something else that has to be considered is that there are many ways besides hours of light in which indoor starting varies from outdoor growing. For one example, while outdoor plants in most areas have less than 24 hours of light, they get it from a source that is a whole heap brighter than grow lights and which produces light of different composition.