Far red effect on plant growth

[Jaz]

After I saw far red discussed in a grow thread on an auto, I just happened across this last night and thought I'd share.
Some takeaways from the clip:
Far red passes through the leaf better than colours lower in the spectrum, reaching lower leaves but also triggers the plant to grow taller which can result in gangly looking plants.
There's pros and cons, far red is better suited to some plants than others.
Causes cell expansion, larger leaves hence good for lettuce spinach, however plants can stretch too much when far red > 5%, reducing the density of your grow.
Can be used to control flowering of long day plants, not useful for flowering of short day plants (Cannabis)
The sun does produce far red but it's counterbalanced by the blues.

j

 

[Buds Buddy]

After I saw far red discussed in a grow thread on an auto, I just happened across this last night and thought I'd share.
Some takeaways from the clip:
Far red passes through the leaf better than colours lower in the spectrum, reaching lower leaves but also triggers the plant to grow taller which can result in gangly looking plants.
There's pros and cons, far red is better suited to some plants than others.
Causes cell expansion, larger leaves hence good for lettuce spinach, however plants can stretch too much when far red > 5%, reducing the density of your grow.
Can be used to control flowering of long day plants, not useful for flowering of short day plants (Cannabis)
The sun does produce far red but it's counterbalanced by the blues.

j

Try watching DR. Bruce Bugby video on the Emerson Effect of Far Red on Cannabis.

 

[Emilya Green]

I am finding very significant positive effects from using 30w of far red light for 20 minutes per day. I run this special light for 10 minutes before the main lights come on in order to reduce stretching, and I run it for 10 minutes after the main lights go off so as to put the plants immediately into the night mode, allowing for more efficient use of the energy gathered during the day. Please look up "trigger lights" to see why farmers have been using them in greenhouses for decades.

I do not believe that Shane or Bugbee are on the right track investigating the use of full time far red light. Nature also does not use a lot of far red, so their conclusions seem to be correct in that far red used in that way is not beneficial. Yes, there does seem to be a bit of an Emerson Effect, but I think the negatives outweigh the positives when far red is used in this way.

 

[bluter]

i see somebody got green while i've been busy eh? @Emilya Green ... lol

personally i think a little far red / ir can be beneficial. it naturally is more prevalent in late season. it's not as large a factor as deep red, but it's there.

some of the issue with the topic is led trying to cram seedling / veg / flower on one light. it's always a compromise. even if you get piles of everything spectrum wise, throwing the sink at the plant doesn't usually work best. natural light evolves through the growing season, plants have evolved in sync.

edit : most far red is early morning / late day with little blue spectrum, and it is very weak or ambient. it's present throughout the day spectrum, but is lessened.

 

[Icemud]

Some different topics involving Far Red

• With far red, its about the ratio of RED:Far red for stretch. the more far red, the more stretch. This is how plants detect they are in the shade and stretch out of the canopy to find sun.. its called shade avoidance syndrome and because in the canopy the levels of green light and far red are higher than in direct sun, the plants use the ratios as a tool to determine if they are shaded or not.
  • With this being known, this could be used full time on short stocky indica's to stretch them out.
• For Photochrome reversion triggering (flower triggering) it can be used at night to rapidly change Pr and Pfr which normally is a long process. This can slightly decrease the flowering time of cycles and help plants mature faster. It can also be used to extend daylight hours slightly more than 12 hours without effecting flowering.
• Emerson effect shows that the combined use of red and far red, pushes photosynthesis higher than the sum of each seperately, and really was how they discovered plants have 2 photosystems.

The sun has quite a bit of far red...

Cheers all.

 

[Emilya Green]

Some different topics involving Far Red

• With far red, its about the ratio of RED:Far red for stretch. the more far red, the more stretch. This is how plants detect they are in the shade and stretch out of the canopy to find sun.. its called shade avoidance syndrome and because in the canopy the levels of green light and far red are higher than in direct sun, the plants use the ratios as a tool to determine if they are shaded or not.
  • With this being known, this could be used full time on short stocky indica's to stretch them out.
• For Photochrome reversion triggering (flower triggering) it can be used at night to rapidly change Pr and Pfr which normally is a long process. This can slightly decrease the flowering time of cycles and help plants mature faster. It can also be used to extend daylight hours slightly more than 12 hours without effecting flowering.
• Emerson effect shows that the combined use of red and far red, pushes photosynthesis higher than the sum of each seperately, and really was how they discovered plants have 2 photosystems.

The sun has quite a bit of far red...

Cheers all.

And so far all of these known studies on far red do not consider the use of these lights for only 20 minutes a day, by using them as trigger lights. I am getting totally different results than they are. Someday I hope that science can tell me why, but until then all I have are my new theories, based on the studies you cite above. Trigger lights in far red. It IS a thing that needs to be studied.

 

[Icemud]

And so far all of these known studies on far red do not consider the use of these lights for only 20 minutes a day, by using them as trigger lights. I am getting totally different results than they are. Someday I hope that science can tell me why, but until then all I have are my new theories, based on the studies you cite above. Trigger lights in far red. It IS a thing that needs to be studied.

I wholeheartedly agree that plant lighting in general is still infantile at best in terms of research, especially for our beloved plant. There is still a lot of mystery surrounding plant lighting, photomorphogenesis, photochemical reactions and just photosynthesis in general. And then once we get to understand it, between different plant species and varieties, mutants and phentype expressions it changes even between different species making the details blurred.

I know even back when I was helping plan out grow facilities a big concern of mine was IR (night vision) cameras and the wavelengths effects on the plants and finding information was extremely difficult if at all available. Definitely wish there was more research on all aspects of plant lighting, and just recently with LED diodes of all wavelengths becomming common the research has been becoming more common, but still not on cannabis.

One of these days I will hit that lotto and have my own canna research facility

If I can remember this weekend I will try searching through my library of PDF abstracts I downloaded a few years ago when I was going really heavy into plant light research and far red. If I find anything in their of worth I will send them to you. I know there were a few but I will have to dig as I was really bad with labeling the files... lol

 

[Jaz]

I run this special light for 10 minutes before the main lights come on in order to reduce stretching and I run it for 10 minutes after the main lights go off so as to put the plants immediately into the night mode, allowing for more efficient use of the energy gathered during the day. Please look up "trigger lights" to see why farmers have been using them in greenhouses for decades.

So in other words, far red is prominent in daylight at dawn and dusk.

I'm wondering, on short days, if I put out my plants at dawn and dusk to capture this light as well as daylight throughout the day and then take them indoors for a supplement of LED during the night to make up for the shortfall in DLI; will those outdoor periods 'in the red' help reduce stretching... or does it 'have' to be at the start and finish of each light cycle?

j

 

[Emilya Green]

So in other words, far red is prominent in daylight at dawn and dusk.

I'm wondering, on short days, if I put out my plants at dawn and dusk to capture this light as well as daylight throughout the day and then take them indoors for a supplement of LED during the night to make up for the shortfall in DLI; will those outdoor periods 'in the red' help reduce stretching... or does it 'have' to be at the start and finish of each light cycle?

j

I think it has to be at the beginning and end of the light period, but I don't rightly know having not ever done that experiment.