LEC - Light-Emitting Ceramic

[Carolina Dream'n]

...as well it should be. You're the latest of a growing list of folks I've heard say these lamps are stretch killers. My girls stretch fine under my 860W CDM, so I don't think it's just a spectrum thing.

Veg is the same for every room. 3-4 days under 4ft 8 bulb T5s. I think it's the lack of a spectrum change from the T5 to the CMH causing the lack of stretch. My plants under the 1000wDE finish around 30 inches, starting at about 6. The plants under 315s never got to above 24 inches, cutting my canopy down 20%.

 

[ttystikk]

Veg is the same for every room. 3-4 days under 4ft 8 bulb T5s. I think it's the lack of a spectrum change from the T5 to the CMH causing the lack of stretch. My plants under the 1000wDE finish around 30 inches, starting at about 6. The plants under 315s never got to above 24 inches, cutting my canopy down 20%.

Heat makes things stretch as well, isn't that right?

 

[Carolina Dream'n]

Heat makes things stretch as well, isn't that right?

AC was modified to keep the 315 room the same temp as others. All measurements are at canopy.

 

[ttystikk]

AC was modified to keep the 315 room the same temp as others. All measurements are at canopy.

Wow, talk about driving out your variables!

Do you have the space and inclination to increase W/ft² with LEC?

 

[GroErr]

I run most of my veg under HPS- because what I want out of my babies IS stretch. Once they hit the trellis, my preference is for them to not bolt quite so much. CDM did this for me compared to HPS, so I'm wondering if veg light spectrum has more to do with stretch phenomena than we might assume.

Veg is the same for every room. 3-4 days under 4ft 8 bulb T5s. I think it's the lack of a spectrum change from the T5 to the CMH causing the lack of stretch. My plants under the 1000wDE finish around 30 inches, starting at about 6. The plants under 315s never got to above 24 inches, cutting my canopy down 20%.

I think we're onto something here, this looks to be the only significant variable. The environment hasn't changed, only lighting/spectrum. I'll do some more digging but I couldn't find any science to back up my thoughts on this last time I looked around. I'm pretty sure it is a significant factor, would be nice to have some hard data, could be used to either reduce or increase stretch as needed.

 

[GroErr]

Here's an article on this that would be interesting to get, can't access it without a subscription, pasting the source and abstract:

http://www.actahort.org/books/272/272_11.htm
CONTROL OF PLANT MORPHOGENESIS AND FLOWERING BY LIGHT QUALITY AND TEMPERATURE
Authors: R. Moe, R. Heins
DOI: 10.17660/ActaHortic.1990.272.11
Abstract:
Elongation of plant stems, flower stalks and leaf petioles, lateral branching, shoot and leaf orientation, and leaf pigmentation are influenced by both light quality and temperature. Morphological responses to light and temperature are referred to as photomorphogenesis and thermomorphogenesis, respectively. Red light (R) or light with a high R/FR ratio (e.g. fluorescent lamps) applied as day-extension or night-interruption (NI) suppresses stem elongation and promotes lateral branching. Far-red light (FR) or light with a low R/FR ratio (e.g. incandescent lamps) strongly enhances stem elongation and inhibits lateral branching. The DIFference between day temperature (DT) and night temperature (NT) defined as DT minus NT = DIF strongly influences internode length and plant height in a wide range of pot and bedding plants, while average daily temperature only slightly influences internode length. Plants grown with a positive DIF (DT>NT) are taller at maturity than plants grown with a negative DIF (DT<NT). The response to DIF is quantitative. For many morphological characteristics, thermomorphogenesis is similar to photomorphogenesis in the following manner: 1) R light (high R/FR ratio) = negative DIF, 2) FR light (low R/FR ratio) = positive DIF. In the long day plant (LDP) Campanula isophylla, DIF interacts with lamp types (high R versus high FR) which indicates that DT/NT alternations interfere with phytochrome mode of action. Leaf unfolding rate and flower development are not affected by DIF, but by average daily temperature. Incandescent (FR) and fluorescent (R) lamps are almost equally effective in promoting early flowering. in some LDP. Incandescent lamps, however, cannot be recommended as proper lamp type for photoperiodic lighting to induce flowering in LDP if compact, well-branching plants are desired. Lamp types with a high R/FR ratio should be used. Practical application of DT/NT treatments and light quality manipulations with different lamp types and time of applications, including elimination of twilight or selective screening of the daylight spectrum, will be discussed.

 

[a senile fungus]

@Sativied

You sent me a link via PM regarding R:FR ratio and phytochrome response some time ago.

I can't find it, do you happen to still have it?

 

[GroErr]

Good article, while it focuses on reducing stretch, there are a couple of nuggets in there (reverse to increase stretch). The light/spectrum switch definitely plays a significant role, particularly when there is a significant difference between the veg spectrum and flowering spectrum (e.g. blue/6500k fluorescent to hps which is an extreme difference).
http://www.manicbotanix.com/hydroponic-grow-guide/reducing-stretch-in-indoor-crops.html

 

[mc130p]

Here's an article on this that would be interesting to get, can't access it without a subscription, pasting the source and abstract:

http://www.actahort.org/books/272/272_11.htm
CONTROL OF PLANT MORPHOGENESIS AND FLOWERING BY LIGHT QUALITY AND TEMPERATURE
Authors: R. Moe, R. Heins
DOI: 10.17660/ActaHortic.1990.272.11
Abstract:
Elongation of plant stems, flower stalks and leaf petioles, lateral branching, shoot and leaf orientation, and leaf pigmentation are influenced by both light quality and temperature. Morphological responses to light and temperature are referred to as photomorphogenesis and thermomorphogenesis, respectively. Red light (R) or light with a high R/FR ratio (e.g. fluorescent lamps) applied as day-extension or night-interruption (NI) suppresses stem elongation and promotes lateral branching. Far-red light (FR) or light with a low R/FR ratio (e.g. incandescent lamps) strongly enhances stem elongation and inhibits lateral branching. The DIFference between day temperature (DT) and night temperature (NT) defined as DT minus NT = DIF strongly influences internode length and plant height in a wide range of pot and bedding plants, while average daily temperature only slightly influences internode length. Plants grown with a positive DIF (DT>NT) are taller at maturity than plants grown with a negative DIF (DT<NT). The response to DIF is quantitative. For many morphological characteristics, thermomorphogenesis is similar to photomorphogenesis in the following manner: 1) R light (high R/FR ratio) = negative DIF, 2) FR light (low R/FR ratio) = positive DIF. In the long day plant (LDP) Campanula isophylla, DIF interacts with lamp types (high R versus high FR) which indicates that DT/NT alternations interfere with phytochrome mode of action. Leaf unfolding rate and flower development are not affected by DIF, but by average daily temperature. Incandescent (FR) and fluorescent (R) lamps are almost equally effective in promoting early flowering. in some LDP. Incandescent lamps, however, cannot be recommended as proper lamp type for photoperiodic lighting to induce flowering in LDP if compact, well-branching plants are desired. Lamp types with a high R/FR ratio should be used. Practical application of DT/NT treatments and light quality manipulations with different lamp types and time of applications, including elimination of twilight or selective screening of the daylight spectrum, will be discussed.

I couldn't find that one, but I found this full text, which cites that one:
http://www.sciencedirect.com/science/article/pii/030442389190161Q
Stem elongation and flowering of the long-day plant Campanula isophylla Moretti in response to day and night temperature alternations and light quality

Roar Moe a, Royal D. Heins b, John Erwin b
Show more

doi:10.1016/0304-4238(91)90161-Q


Abstract
Stem elongation and plant height at flowering in Campanula isophylla Moretti were greater when plants were exposed to far red (FR) light or light from incandescent lamps which had a low red (R)/FR ratio (0.7). The difference in final stem length between FR- and R-light-treated plants was greatest when the light treatments were given during the entire night or as a 3 h end-of-day (EOD) lighting period. Only minor differences existed between R and FR light treatments when plants were given light in the middle of the night. However, FR light suppressed lateral branching compared with R light. The reduction in plant height as a result of a lower day temperature (DT) than night temperature (NT) was nullified by day-extension lighting with incandescent lamps. With fluorescent lamps (R/FR ratio 4.2), plant heightwas significantly less at 15/21°C (negative DT-NT (DIF)) than at 21/15°C DT/NT (positive DIF). Continuous lighting (CL) during the entire night or with 3 h night interrupttion (NI) treatments with R or FR light immediately after the middle of the night was equally effective at inducing flowering, and much more effective than EOD or end-of-night (EON) lighting. DIF had a slight influence on the rate of flower development, but negative DIF grown plants had 24% more flowers and flower buds, and 26% higher dry weight, than positive DIF plants. Practical applications of light quality and negative DIF treatments for the production of high-quality pot plants of C. isophylla are discussed.

 

[Carolina Dream'n]

Wow, talk about driving out your variables!

Do you have the space and inclination to increase W/ft² with LEC?

Thinking about adding a few more an see how they do watt for watt. Their expensive little boogers though, over 500 a piece.

 

[ttystikk]

I couldn't find that one, but I found this full text, which cites that one:
http://www.sciencedirect.com/science/article/pii/030442389190161Q
Stem elongation and flowering of the long-day plant Campanula isophylla Moretti in response to day and night temperature alternations and light quality

Roar Moe a, Royal D. Heins b, John Erwin b
Show more

doi:10.1016/0304-4238(91)90161-Q


Abstract
Stem elongation and plant height at flowering in Campanula isophylla Moretti were greater when plants were exposed to far red (FR) light or light from incandescent lamps which had a low red (R)/FR ratio (0.7). The difference in final stem length between FR- and R-light-treated plants was greatest when the light treatments were given during the entire night or as a 3 h end-of-day (EOD) lighting period. Only minor differences existed between R and FR light treatments when plants were given light in the middle of the night. However, FR light suppressed lateral branching compared with R light. The reduction in plant height as a result of a lower day temperature (DT) than night temperature (NT) was nullified by day-extension lighting with incandescent lamps. With fluorescent lamps (R/FR ratio 4.2), plant heightwas significantly less at 15/21°C (negative DT-NT (DIF)) than at 21/15°C DT/NT (positive DIF). Continuous lighting (CL) during the entire night or with 3 h night interrupttion (NI) treatments with R or FR light immediately after the middle of the night was equally effective at inducing flowering, and much more effective than EOD or end-of-night (EON) lighting. DIF had a slight influence on the rate of flower development, but negative DIF grown plants had 24% more flowers and flower buds, and 26% higher dry weight, than positive DIF plants. Practical applications of light quality and negative DIF treatments for the production of high-quality pot plants of C. isophylla are discussed.

Twenty six percent MORE weight by having nighttime temperatures EXCEED daytime temps?? Did I read that correctly??

 

[GroErr]

I couldn't find that one, but I found this full text, which cites that one:
http://www.sciencedirect.com/science/article/pii/030442389190161Q
Stem elongation and flowering of the long-day plant Campanula isophylla Moretti in response to day and night temperature alternations and light quality

Roar Moe a, Royal D. Heins b, John Erwin b
Show more

doi:10.1016/0304-4238(91)90161-Q


Abstract
Stem elongation and plant height at flowering in Campanula isophylla Moretti were greater when plants were exposed to far red (FR) light or light from incandescent lamps which had a low red (R)/FR ratio (0.7). The difference in final stem length between FR- and R-light-treated plants was greatest when the light treatments were given during the entire night or as a 3 h end-of-day (EOD) lighting period. Only minor differences existed between R and FR light treatments when plants were given light in the middle of the night. However, FR light suppressed lateral branching compared with R light. The reduction in plant height as a result of a lower day temperature (DT) than night temperature (NT) was nullified by day-extension lighting with incandescent lamps. With fluorescent lamps (R/FR ratio 4.2), plant heightwas significantly less at 15/21°C (negative DT-NT (DIF)) than at 21/15°C DT/NT (positive DIF). Continuous lighting (CL) during the entire night or with 3 h night interrupttion (NI) treatments with R or FR light immediately after the middle of the night was equally effective at inducing flowering, and much more effective than EOD or end-of-night (EON) lighting. DIF had a slight influence on the rate of flower development, but negative DIF grown plants had 24% more flowers and flower buds, and 26% higher dry weight, than positive DIF plants. Practical applications of light quality and negative DIF treatments for the production of high-quality pot plants of C. isophylla are discussed.

This one is focused on temp differences and R/FR effects, would be cool to try that negative DIF environment, 25% increase in bud would be nice - lol. That second link I posted has a good explanation of the light temperature (K) if I'm getting it right. It's suggesting that the greater the difference in colour between veg and flower lighting, the greater the stretch. That lines up with my thoughts on having the different light sources for veg/flowering. Good discussion, unfortunately it doesn't help @Carolina Dream'n but good info on this.

 

[TheChemist77]

under 2 600 hps my strain would easily double its height in flower closer to 2.5 to 3 x height after 1 week of veg, since my switch to cmh my plants stretch less yes,, but my first run had only a few days of veg from rooted clones.i also take small clones just as a note, 2 sets of leaves maybe 3 inches tall with an inch below the collars.... now on my second run, same strain i vegged 2 weeks and plants have all doubled height to fill my space, with my 6 plants on right and left sides stretching even more than the 3 middle rows..with no topping or training they branched out very well too.
Carolina Dream'n,, please see my journal i have pix showing the plants stretch rate...my first run with cmh got 1.1 gpw,, i expect future runs to get even better..BTW my patients have all said the lamp change has improved potency and buds are tighter than under hps or hps and mh both..
also ive always noticed with hps or mh that my clones as generations go by they adapt better to suit my grow.. so as generations go by i expect the same to happen under the new lamps..as stated this is only my second run with cmh so with each new run and each new generation of clone/clone moms plants should adapt or improve to the lamps...

 

[mc130p]

This one is focused on temp differences and R/FR effects, would be cool to try that negative DIF environment, 25% increase in bud would be nice - lol. That second link I posted has a good explanation of the light temperature (K) if I'm getting it right. It's suggesting that the greater the difference in colour between veg and flower lighting, the greater the stretch. That lines up with my thoughts on having the different light sources for veg/flowering. Good discussion, unfortunately it doesn't help @Carolina Dream'n but good info on this.

.... yeah, i didn't read it....read so many research papers every day.....it looked from the abstract to focus on temp, but based on the title it seemed to cover the lighting as well....guess not, haha.

 

[ttystikk]

.... yeah, i didn't read it....read so many research papers every day.....it looked from the abstract to focus on temp, but based on the title it seemed to cover the lighting as well....guess not, haha.

I read the abstract and it spoke about both lighting and temperature affecting stretch.

 

[Rahz]

Interesting topic. I think strain is the primary variable so I would be curious to know that as well as seeing side by side grows using a control.

OTOH, If anyone can stop headband stretch in the 2-3 week period I will be a believer. HB can keep stretching into week 4 under 3000K Vero v1.

 

[GroErr]

.... yeah, i didn't read it....read so many research papers every day.....it looked from the abstract to focus on temp, but based on the title it seemed to cover the lighting as well....guess not, haha.

All good reading though, it's all related, temps & lighting can have huge effects. A couple of years indoor and feeling more like a university student than a grower - lol

 

[ttystikk]

All good reading though, it's all related, temps & lighting can have huge effects. A couple of years indoor and feeling more like a university student than a grower - lol

Right? That's what keeps it so interesting for me! As a self professed specialist in using environment to improve yields, I found the part about nighttime temps and yield was both fascinating and highly relevant.

 

[ttystikk]

Interesting topic. I think strain is the primary variable so I would be curious to know that as well as seeing side by side grows using a control.

OTOH, If anyone can stop headband stretch in the 2-3 week period I will be a believer. HB can keep stretching into week 4 under 3000K Vero v1.

Based on the abstract above, I can propose a course of action right now; get some 5000k+ lighting into the first few weeks of bloom. 6500k will work even better to arrest stretch.

 

[mc130p]

well, if you come across any you want to read, but lack 'access,' send me a PM and i'll get it for you.