Do they grow towards the light?

[f-e]

Non of my plants grow towards my leds. If one side is illuminated better, it will grow bigger, but not a single growing tip is heading towards any of my cob's.

I don't have a HID grow to look at right away. Can anyone offer any further observations?


Perhaps our plants grow towards the warmth. Then I picture my outdoors and realise they put lots of branches out away from the suns path. As do all plants.

Is it a myth that plants grow towards the light? I can't support the argument.

 

[Red October]

You might need to use a meter to measure the lumen output at the growth tips. Seems sativas prefer a certain range and anything above is a negative.

With led lights it seems that because of the lower heat production they get placed closer to the plants but the plants can also handle only a certain amount of lumens per a square inch in reality.

I don't have any experience with led lighting but I have done quite a bit of reading lately and this seems to be a common issue with strong led lights along with higher N issues as the plants don't seem to take it up as readily.

 

[Sunshineinabag]

This is why I adore this site

 

[f-e]

Very good Red. It ties in with some other thoughts I have been having. What I'm looking at here is just 40w from 4 cobs over 6sqf. So like 8w a foot. So it won't be to bright this time. In fact, I see 25,000lux just a few inchs from the lamp and 10-15k over most of the canopy. Low by any standard.

 

[jwm]

lol

 

[Agronomist]

.

 

[f-e]

Looking down doesn't elevate you. It just stops you moving forward.

 

[Brother Nature]

It sounds like they're just not getting enough light. I had a look at my veg tent after reading this thread and all the clones are definitely growing towards the light, in that 'praying hand' way. They are sitting under 6x cobs @ 320w though so considerably more light. Interesting to think about though, I've definitely seen outdoor plants that grow fatter than they do taller so perhaps it's a strain dependent trait?

 

[GMT]

My young clone tops do point to the light source, my flowering plants have had Si, fed to stiffen stems etc and don't move in reaction to light source. I also notice the young clones have longer, stiffer branches on the side that the light source hits first.
Just personal observations.
(My clones are side lit with a warm white 9w led bulb.)

 

[VerdantGreen]

Cannabis does display phototropism..(movement in relation to light) but often rather than the stems bending, the petioles (leaf stems) will do the bending so that they present at right angles to the strong light source. Growing tall and lanky when shaded is also an example of phototropism and it is the ratio of far-red spectrum intensity on the canopy compared to the lower leaves that dictates how much you get.


VG

 

[VerdantGreen]

Looking down doesn't elevate you. It just stops you moving forward.

Agreed. It was me who requested this forum... and i didn't ask for it so that people could take the piss out of others who are trying to learn.


VG

 

[St. Phatty]

= Phototropic.

plants don't just bend towards the light.

if you were mechanically inclined, you could use that slow motion force to wind a watch or something.

 

[BongFu]

his in cannabis botany? Yeah according to Charles Darwin 1870 totally. It's called phototropism. xxxxxxxxx

 

[Benny106]

The plants are smart...they make us hang lights in the first place.

 

[f-e]

Oh, the leaves track the light, not the shoots. I had heard this before but don't tend to file things I don't think I can use. I had been reading about sunflowers who's heads follow and interestingly track back in the night, so could wind a watch.. They were also finding there that Blue light was quite governing, and oddly with just red they stretched less.

I swear I have had buds round the walls falling back in towards the light with HID's as a general occurrence. Getting them out on a net meant letting them go up and then adjusting that height to become reach. Training LED plants has been different. At one time I got some far-red+infra-red in to get that stretch and what I'm really churning over with this post. That using light right out past 900nm had made my LED plants show dominant heads. In general my LED buds are all about the same size. Like no growing tip held the others back. I saw this in my side by sides to. Where each had some effect on the other.

I'm not good with the terms, but the act of a head taking the lead and suppressing others seems related to IR which is why I titled the thread about Light. Sunflower people feel it's heat the sunflower follows, not light.

I'm going to use the far emitter again to reproduce the same conditions as last time. Hoping to again see domenance in some tips leading to main cola's and secondary and scratch. Not lots of samey buds.

My emitter picks up about where an LM301 fades away. Giving a pretty flat response right out past 800.
Yes.. It's a halogen lamp. Very very efficient at the non visible spectrum. So just 10-15% of my lighting load.

I feel quite sure I will see them grow towards that heat source.

Any holes? contrary observations? Shared feelings on the subject?

 

[Sunshineinabag]

https://open.spotify.com/track/6u13tCUeMafkT0KFsmvodB?si=i4irTWi6TFyeARUBXPCH3A



I can tell that we are gonna be friend's! Id like to thanks to you all for information being gleaned here

 

[VerdantGreen]

f-e, your observations are good and you are on the right lines....
Far red - it is the ratio of far red light on the canopy to the lower leaves that influences stretch... so yes it is related to the growth tip 'taking the lead' and growing taller (called apical dominance)
The mechanism of apical dominance isn't controlled by far red... it is controlled by auxin (a plant growth regulator) - the highest tip produces auxin which stops the sideshoots from developing... bend it down or cut it off and no auxin - and the sidebranches start to grow.
this thread has a paper about the far red ratio influencing stretch
https://www.icmag.com/ic/showthread.php?t=194053


whether it is heat or light that makes sunflowers move to face the sun... who knows.. but to a plant without eyes it is all just different wavelengths on the electronagnetic spectrum anyway !



VG

 

[PDX Dopesmoker]

Its not even different wavelengths on the electromagnetic spectrum to them, they react to quanta of different momentum values. The badly misnamed photosynthesis works just the same if you bombard the leaf with electrons which carry the same energy that photons of the correct wavelength do.

You might need to use a meter to measure the lumen output at the growth tips. Seems sativas prefer a certain range and anything above is a negative.

With led lights it seems that because of the lower heat production they get placed closer to the plants but the plants can also handle only a certain amount of lumens per a square inch in reality.

I don't have any experience with led lighting but I have done quite a bit of reading lately and this seems to be a common issue with strong led lights along with higher N issues as the plants don't seem to take it up as readily.

I think growing under LEDs is a little weird because the ratio of growth band energy is so high. Under any broadband source of light all of that waste light thats not in the preferred wavelengths is still there to cause evaporation, but not under LEDs. LEDs work great for growing plants, but you can feel that the light is weak & thats not only because LEDs run cool, its also because the photon pressure is low under them compared to broadband light sources. LEDs produce less photons overall than other lamps do. I thought this up when I was noticing that wet soil takes forever to dry out under LEDs if there isn't a plant in the soil to suck all the moisture out. I brought some big containers of dirt inside that had been sitting out in the rain for a month and I started some seeds in them under LEDs & it was weeks before I had to water the first time, I don't think it would've been that long under 18 hours of continuous sunlight. Sunlight is incredibly wasteful, most of those photons are outside the pot plant growth bands.

 

[hayday]

For well over ten years I have run a vertical garden. I have never follow any kind of belief that cannabis grows towards the light. The leaves on my plants orientate to the brightest light but all the branches do their thing and grow in all directions including, but not only, towards the light.
Bare bulb, HPS and LED with little or no overhead lighting or no screen, all it takes is an occasional stake to keep a random shoot out of the lights.

 

[Lester Beans]

Most people don't have the patience, but take the plant that has leaves turn towards the light and turn it around. Now just watch. It takes about 20-30 min for the leaves to turn back towards the light. Little twitches and shakes happen and suddenly the leaves are back pointed towards the light.

Also with plants that are slightly wilted before watering. Water them and watch as the perk back up, twitching and doing plant things. It is cool to watch at least once.