Help with lighting please

[Jaqs]

All plants are in same grow room, two of them ready for 12/12, 4 still need 18/6, is it ok to put the light to 12/12?

Jaqs Reviewed by Jaqs on 02-05-2014. Help with lighting please All plants are in same grow room, two of them ready for 12/12, 4 still need 18/6, is it ok to put the light to 12/12? Rating: 5

[Weezard]

Only if you want them all to start flowering.

[Jaqs]

Would it be ok to leave it at 18/6 for now even though there's some "bigger" plants in there too?

[tlranger]

Just remember they will continue to 'grow' while flowering, most will almost double in size.

[crystaliscious]

Just remember they will continue to 'grow' while flowering, most will almost double in size.

Ranger I have been playing with cuttings- leaving them in blue veg x 2 wks, moving to 12/12 in BLUE for 2 wks ( they don't stretch much at all) then moving them over to mixed red/blue - the stretch is more consistent…..is this luck or something that may be working?

[tlranger]

Have been reading with interest for some time, about the colors in led's. Know that Weez sure swears by them, and cat swears by t5's. But think the common denominator is strong light, kept close will produce your stumpy plant. I don't mind a little larger plant little more time but more bud per plant, IMO. But still I start bloom under Mh and end under hps. Have been looking at led's this morning, found a 1000 watter, but it sounded to be full spectrum, need more input from the master Weez.

[Weezard]

Howzit TL?

I'm by no means a master, but I'll be happy to share what I have learned.

• HID lamp: Source efficiency is typically 120 lumens/watt or higher. However, losses from trapped light, protective covers and lenses, inefficient ballasts and unfavorable operating temperature typically result in a measured system efficiency of 30 lumens/watt or less.
• LEDs: Source efficiency can be 100 lumens/watt or higher, depending on the type and manufacturer of the LED used. There are no losses from trapped light due to the focused output of the LED, and secondary optics and protective covers generally reduce output by only 25% or less. LED power drivers are also more generally efficient than HID ballasts, and reduce system efficiency by 10-15%. However, even when efficiency reductions due to high operating temperatures are included, LED system efficiency often remains above 50 lumens/watt or higher.

That is base on 2007 figures and on the surface says that HPS produces 2X the lumens per Watt.
That is because it measures lumens.
We are more interested in the PAR value, yah?

Attachment 298270

The bandwidth of sodium vapor is less than ideal for growing weed.
Much of it is not absorbed.
Makes the leave look bright yellow as it bounces off.
What does get used has to be up-converted by the plant, and that requires energy.
There goes your efficiency.

White leds are not that much cheaper to run than T5s or CFLs, until you factor in replacement costs.
For short term use, (2 or 3 grows), with full spectrum light, I would use T5s or T8s.

Where LEDs really shine, is narrow bandwidth lighting.
I target the absorption peaks for Cannabis and waste no watts on the rest of the colors.
That includes IR and UV.
10 Watts of well targeted light is worth about 18 Watts of white light.

So, it is my opinion that 1000W. of full spectrum light is wasting a substantial amount of power on less productive illumination.
~600W. of targeted leds will pull the same weight.

There is added advantage to di-chroic lighting in control of the morphology.
Increase the blue and the internodes stay short.
Increase the red and we make them stretch.

Now, I'd like to address the proximity.
But my wee beasties are wanting attention.

I'll save it for another post.

Suffice to say that keeping LED lighting too close to the canopy is a bad idea.

And it's not just light saturation causing growth cessation.

Think, Inverse square law vs. plant height, alright?

Attachment 298269
More later, or upon demand.

Aloha Y'all
Weeze

[tlranger]

Okay, the thread is help with lighting so I figure no thread hacking here, good a place as any. Please excuse my apparent thick headed Ness. Probably is age or IQ related, or the fact that I can't get Bb ex-friend's picture out of my brain.

Think I have a partial handle on indecency, I mean efficiency, hot ballast, dirty bulbs, dirty covers on hoods, even the hole for the cooling tube is like a spot light on the wall!!

And realize I was always going after lumens, here is the first place I've heard of PAR, what is it? Percentage of absorbed radiation(a quess). From you graph it appears that chlorophyll a&b get their power at a band~410-460 and another boost at a band~650-680. So we want to max these and not waste energy on others. Which is why leds look like their made of colored lights? Instead of going with a full spectrum?

Next questions deal with your focused our lenses light. This means down instead of all around? But your still getting coverage, based on you inverse square law. Being cooler you can run closer? Till you have a bunch of focused points and not real coverage?

Morphology, penetration, proximity, my mind is wandering again, curse you Bb!! What did you do, leave the gate open.

[Weezard]

"I've heard of PAR, what is it?"

Photosynthetically active radiation.

Lumens are for humans.

Proximity is not just about heat.
Especially where lensing is used.

For this, I gotta use LUX, (lumens per square meter)

At ~ 91k Lux Cannabis saturates and stops growing.
In the tropics, we would lose about 2 hours a day in growth if we didn't use shade cloth.
If you exceed ~93k Lux you start to get light bleaching which is permanent damage.

Saw a guy buy good led panels, then hang them 2" from his plants.
When the plants quit growing, he didn't waste any time thinking about it, he pronounced the leds to be crap and whined, online, for months.

That, and if an unlensed light is only 4 inches from the crown.
What does the ISL say it will drop to at 8 inches down?!
And then, at 16"?

That's what "penetration" really means.
It's not about shadows.
Sun movement and wind mitigate shading.

It' is, and always has been, about distance, when growing under lights.
The higher above the canopy you can keep your lights, the more, so called, "penetration" you will get.
And that mean bigger trees with green leaf all the way down, indoors.

Lensing, limits the area covered, but allows plenty of headroom at saturation levels.
It's a reasonable workaround to the ISL limitations.

Fingers are tired.
I do run on!

Aloha,
Weeze

[crystaliscious]

Bud bro was just checking that ticker ranger!!!:thumbsup: