Leaves turning yellow/brown on sides & curling! (PICS INCLUDED)

[ComfortablyNumb]

It's probably a Lux meter.

 

[Aqua Man]

You can raise or lower the light. A light over 12 inches I think causes stretch. I like mine at 16 inches and I get a 1.5-2 inch nodal spacing.
If I raise it to 20 inches, they shoot up to it in a day or two. Mostly I keep it around 14-16.

Actually contrary to previous thought... intensity plays a very small role in stretching unless it is severely reduced.

It's more the ratio of blue/red and far red.

 

[Aqua Man]

Those are the wattages of each light. I have a pH, light and water multimeter that reads my plants are receiving 400-500 units (not sure what the name of the units are). I can take a picture of my meter with the lights on when I get home.

400-600 is likely par and that's to high for small plants. Max in veg is 400-600. 600 if all things are in a great place including plant health. 600-800 in flower but that's due to the reduction of the photo period.

I be 300ish until they improve.

 

[ComfortablyNumb]

Actually contrary to previous thought... intensity plays a very small role in stretching unless it is severely reduced.

It's more the ratio of blue/red and far red.

That does not make sense. My current lights have zero blue or red. White only. (Yeah, I know, YOU pay for 'em)
Yet, I get great stretches or midgets depending on light placement.

 

[Aqua Man]

Been a while since I posted this linn but it's a really good collective source on spectral effects.

Frontiers | An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (...

www.frontiersin.org

 

[Aqua Man]

That does not make sense. My current lights have zero blue or red. White only. (Yeah, I know, YOU pay for 'em)
Yet, I get great stretches or midgets depending on light placement.

Well white contains both... but also green unlike blurples. A 4000k will give shorter interdode spacing and keep plants a fair bit more squat than a 3000k

 

[Steveystrappa]

I've had best luck with small 6400k cfl bulbs in seedling /early veg phase. Depending on how many plants you can get away with 2 or 3 24-36 wat 6400k cfl. In early stages of life. Then I use my mars hydro and other led setup. You have to play around for yourself and learn from experience to what best suits you. That's the fun of gardening. Your always learning and adapting and experimenting!

 

[Steveystrappa]

A couple of these bad boys do the trick in first few weeks

 

[Steveystrappa]

I believe par is just the spectrum of different colors. Ppfd or Photosynthetic Photon Flux Density is the actual intensity of light that is reaching different sections of canopy. Also umol is another way to measure density of light

 

[Steveystrappa]

400-600 is likely par and that's to high for small plants. Max in veg is 400-600. 600 if all things are in a great place including plant health. 600-800 in flower but that's due to the reduction of the photo period.

I be 300ish until they improve.

I agree. They say sometimes and I mean SOMETIMES growers get away with maybe 1200 tops ppfd across canopy but that's in full blown flower and under OPTIMAL conditions

 

[Aqua Man]

I believe par is just the spectrum of different colors. Ppfd or Photosynthetic Photon Flux Density is the actual intensity of light that is reaching different sections of canopy. Also umol is another way to measure density of light

Yeah ppfd and par are commonly used interchangeably. But you are right incorrectly. Such as par meter etc.

Par is a range of spectrums though if we are going to be technical not a measurement of spectrum

 

[Aqua Man]

I agree. They say sometimes and I mean SOMETIMES growers get away with maybe 1200 tops ppfd across canopy but that's in full blown flower and under OPTIMAL conditions

With co2 supplementation.

 

[Steveystrappa]

Yeah ppfd and par are commonly used interchangeably. But you are right incorrectly. Such as par meter etc.

Just wanted to be a smart ass lol. You know I love you haha and exactly what I meant with c02 supplements

 

[ComfortablyNumb]

Been a while since I posted this linn but it's a really good collective source on spectral effects.

Frontiers | An Update on Plant Photobiology and Implications for Cannabis Production

This review presents recent developments in plant photobiology and lighting systems for horticultural crops, as well as potential applications for cannabis (...

www.frontiersin.org

Good paper. So, the intensity is important because it's what drives the spectra to the plants, but it's the various spectra that influence the growth hormones. So both are needed.

 

[ComfortablyNumb]

If they change the lights to small units that are dedicated to their spectrum, you could line the grow area walls, floor and ceiling with units at lower intensity and have a better grow.

Man, I want to do a light experiment now. Ok, Who's gonna finance it?

 

[Aqua Man]

Good paper. So, the intensity is important because it's what drives the spectra to the plants, but it's the various spectra that influence the growth hormones. So both are needed.

Absolutely and the closer to saturation the more important the ratios become. Lights are exactly like nutrients in that aspect. Ratios have a huge impact morphology and only really become more important to the photosynthesis side of things when a spectrum start to get to its upper limits.

Pretty much intensity trumps all for photosynthesis and spectrum is more related to structure and plant processes. But with that said while green is less efficiently absorbed it penetrates the canopy more efficiently than any other spectrum so it's creating photosynthesis where there would be none. All spectrums are very important and the ratios of them in relation to one another for optimal growth and cannabinoid, terpene and flavinoids is where we are at now.

This is why we are seeing much more incorporating far red and UV. But like ibsay it's like nutrients.... the ratios are the next key to unlock.

 

[Aqua Man]

If they change the lights to small units that are dedicated to their spectrum, you could line the grow area walls, floor and ceiling with units at lower intensity and have a better grow.

Man, I want to do a light experiment now. Ok, Who's gonna finance it?

There are so many well controlled ones going on... just give it 6 months to a yr and the knowledge that comes out will be much better.

 

[Steveystrappa]

If they change the lights to small units that are dedicated to their spectrum, you could line the grow area walls, floor and ceiling with units at lower intensity and have a better grow.

Man, I want to do a light experiment now. Ok, Who's gonna finance it?

I'll help out with some funding but I wanna have fun too!

 

[ComfortablyNumb]

Absolutely and the closer to saturation the more important the ratios become. Lights are exactly like nutrients in that aspect. Ratios have a huge impact morphology and only really become more important to the photosynthesis side of things when a spectrum start to get to its upper limits.

Pretty much intensity trumps all for photosynthesis and spectrum is more related to structure and plant processes. But with that said while green is less efficiently absorbed it penetrates the canopy more efficiently than any other spectrum so it's creating photosynthesis where there would be none. All spectrums are very important and the ratios of them in relation to one another for optimal growth and cannabinoid, terpene and flavinoids is where we are at now.

This is why we are seeing much more incorporating far red and UV. But like ibsay it's like nutrients.... the ratios are the next key to unlock.

Totally.
We can have better grows if we double the emitters and cut the intensity by 60%
And the light system needs to be able to adjust the ratio for best results.

 

[ComfortablyNumb]

I'll help out with some funding but I wanna have fun too!

LOL! Thanx man but I don't have the room. I wish!
But I'm going to take some notes and send Bugbee an email and ask some pointed questions.
I think I'm getting close to a new LED system design....