phytochrome manipulation

[Mendoli]

Yes it should depending how much light you use and how long the splash is. You may be better off using white light though as phytochrome isn't the only pigment involved. One study I have seen said that 660nm in brasssica wasn't enough alone and blue green was needed as well

Thanks Homesteader. I switched from 24/0 to 18/6 last night and my 5 week/6 node girls are suddenly showing preflowers. I’m out of space with no green/hoop house so I’m feeling backed against the wall. Wishing someone knew a way to get plants from the room to outdoors by May 1st without flowering. As each day passes gets more stressful as I’m not confident with any one option at the moment.

 

[growlights]

Since Pr-Prf is almost instant transformation it's far far better to pulse the light during the dark period than on for a few minutes at a time this is what I do by continually flashing FR over the dark period we also reduce/eliminate the risk of hermies through light leaks.

I had to use a circuit I bought off ebay to control a relay to do it 1 second on every 3 minutes for lights off.

We've had a lot of success with strawberries (Extending their season) and chrysanthemums forcing flowering under lighting. At the moment though we're growing chillies which are meant to be day neutral but we've definetly noticed a difference in flower formation under 12/12 (3-4 times faster) one wonders if autos will exhibit the same traits.. I've not treated chillies with FR yet that will be the next grow.

I no longer grow cannabis but have several tents running at any one time full of legal plants.

I've grown plants under 14 hours lights 10 hours dark flashing FR at them (Also more than once) and I never saw a half/half I got healthy plants that went fully into flower and yielded well.

Maybe you should try different strains next time, get a better FR lamp or increase the intesity of FR although I use a 17w lamp to cover 9m2 floor area with no issues. I've been told I cover twice that area no issues.

I purchase my FR lamps directly from philips grow lighting department I don't use Chinese no name crap.

The 20 watt Flower Initiator is now the same price as the 10 watt units once were.

 

[Nugbender]

I understand with being ill and all.. But like I was saying.. If the 660 is contaminated... Meaning Blue/UV light is present when flashed or used as a PAD light .. Then you will get a false positive. Hence why most people think 660 can't be used in the darkness.. But it can.

And if it didn't get confusing enough.. This is how you need to test for UV contamination in red 660 led's.

This quote is from Sal in a previous post on a diff thread/board.

" The plants are just as UV sensitive as they are Blue light sensitive and will trigger at radiance levels as low as 1/5th Watt per Square Foot of monochromatic radiation if it appears between the 280 to 520nm band. The veg trigger bands.

Detecting UV contamination is a little more tricky than detecting visible Blue light contamination. You need to expose phosphors with some Blue emission directly to the LED (and other) radiation and observe the phosphor looking through a Blue filter. If UV is present the phosphor will emit some Blue light that is visible through the Blue Filter, which blocks out the Red.

UV from Red and other LEDs -
With the demand for higher output LEDs and especially with the popularity of the Dogma that UV increases potency, LEDs producing secondary UV emissions are being manufactured in china and marketed for plant growth and they are appearing on the market.

Part of the situation is that the best emitting LED us "Clearlake" cases which do not filter out UV. "

I avoid all this crap and use the filters I showed U from above if I use 660nm led's.. lol

As I stated in a previous post.. Using 660nm LED as PAD lighting gets kind of tricky.. It's not easy seeing UV or Blue light bleed..

But you will know you have it because the RED 660 led's being used will cause a blue/UV veg trigger.. (hence PAD is a Hoax). See my point?

Here is how I practice this PAD stuff on the cheap.

Anyone that wants to play around with this PAD method using real cheap bulbs... The below bulbs can be used.. No the red cfl is not pure 660nm.. It's basically 600 through 720nm. I will also put up the spectrum chart. But the red cfl works just fine on the cheap and has NO blue light contamination..

The reptile Black incandescent bulb is used as a cheap far red 730 source..

*Note: You can only use Black INC bulbs for a cheap far red source. NOT black florescent bulbs.. Black light Fluorescent bulbs have zero far red 730nm emission and are worthless for growing plants.. Just thought I would clear that up from an earlier post. :)

View attachment 381160 View attachment 381161 View attachment 381162

How much are these bulbs? Researching into phytochrome manipulation and different light spectrums to adjust during flower. Currently rocking the chilled logic pucks v2 w/ 660nm far red supplemental thats on the same time as lights + 15 minutes after lights out.

 

[weedtech]

Ah. This is an interesting thread. Folks always trying to figure out how to fuck around with hormones, since that drives most activity on the planet.

 

[johngaudiphx]

I would use the blue 24/0, use a hps for the first 12 hours and FR for the 2nd 12 hours only for sexing the plant, not flowering.

Still flower under HPS but would they're be any benefit to giving UV-b for 24 hours a day if you're giving FR during the dark period?

We all know UV-b is meant to be frostier buds so why not 24/0.

I only want LED's because they great for small scale experiments and the lamps to do this properly aren't available yet. I do have to wonder about 24 hour flowering or more precisely 20 hour flowering and 4 hour rest using combination of lights just for fuck about purposes. I'm going to grow some fucked up plants I'm sure but that's part of the fun.

From the attached PDF

They're saying FR will supress Elongation not encourage it when used with R.

R:FR plants had increased photosythesis!


Shade avoidance! It's the abscence of R:FR on the lower leaves that causes the stretch!

I misread this the first time, Hmmm, I think I understand why they sell a mixed colour version now, very interesting.



Jsan was talking about pure blue not UV, see bopttom chart for UV wavelengths.

I need LED's in the 280-315nm range it's UV-b I want for frostiness and UV-c for germicidal warfare.

I might do a pure LED grow so I can fuck about with wavelengths, not worried about yield at all I've got a couple of HPS for actual yield and since I only grow 1 or 2 plants a time normally plant numbers isn't an issue.

This time I've got 11 plants on the go but normally it's 1 or 2.


I've been told ~250nm is a good wavelength for UV-c LED's for my purposes wattage unsure.




I think it's commonly accepted that UV-a or blacklight has little to no affect for our beloved herb so 315-400nm is essentially a dead wavelength to us (Glad I didn't order 350nm LED's now)

are we sure about this? a good friend of mine told me that years ago she one time grew a plant in a cardboard box with only a blacklight. Like the type that you would use around or underneath a blacklight poster. she did not finish the grow or ever flower the plant she did say that the month and a half or so that she was growing this plant in this box it grew slowly it stayed small and the strange part was that all of the leaves were almost completely covered in white hairs. what I can only assume were trichomes. So I would say that although I didn't do it myself I definitely believe her and what does this say about what backlight actually does I wouldn't say that it does nothing at all.

 

[johngaudiphx]

I quoted this before but I believe it to be very important!

Photoperiodism in a Short-Day Plant

Experiments with the cocklebur have shown that the term short-day is something of a misnomer; what the cocklebur needs is a sufficiently long night.

• Cockleburs (adapted to the latitude of Michigan) will flower only if they have been kept in the dark for at least 8.5 hours — the critical period. (A and B).
• Interruption of an otherwise long night by light — red (660 nm) rays are particularly effective — prevents flowering. (C) unless
• it is followed by irradiation with far red (730 nm) light (D). See spectrum of electromagnetic radiation.
• An intense exposure to far red light at the start of the night reduces the dark requirement by 2 hours (E).

These response are mediated by phytochrome.

Phytochrome

• Phytochrome is a homodimer: two identical protein molecules each conjugated to a light-absorbing molecule (compare rhodopsin).
• Plants make 5 phytochromes: PhyA, PhyB, as well as C, D, and E.
• There is some redundancy in function of the different phytochromes, but there also seem to be functions that are unique to one or another. The phytochromes also differ in their absorption spectrum; that is, which wavelengths (e.g., red vs. far-red) they absorb best.
  
• Phytochromes exist in two interconvertible forms
  • PR because it absorbs red (R; 660 nm) light;
  • PFR because it absorbs far red (FR; 730 nm) light.
• These are the relationships:
  • Absorption of red light by PR converts it into PFR.
  • Absorption of far red light by PFR converts it into PR.
  • In the dark, PFR spontaneously converts back to PR.

http://users.rcn.com/jkimball.me a.ultranet/BiologyPages/P/Photoperiodism.html


This contradicts the 660nm not causing Pr-Prf they effectively kept a plant in veg using a pulsing light mid point through of 660nm.

They also forced flower plants under less dark hours using pulsing FR and pretty much proved for me at least that pulsing FR during the dark hours will eliminate hermies and mean you can visit during lights off with any nm light without interrupting the flower cycle as long as the pulses are close enough together (Every 15mins for 1-5 seconds sounds good to me).

This study to me is the validation of the theory and proof that it does work even if the plant in question wasn't cannabis.

Is there a dif or better link to this by chance? im getting "not found"