Why would one use only part of your LED panel?

[Tead]

When I look at better LED panels, they often include an option to shut off or power down some of the LEDs on the panel.
Of course, different spectrums of light support different phases of growth (bloom and veg), but why would I limit the light going to my plants for any reason? It would make more sense to me to leave all the lights on full power covering all possible spectrums at all times.
I can understand some power consumption issues, but I can't imagine much savings when turn things down a bit.

Am I missing something?

 

[brightlight]

Hello Tead. Mine is a 520 watt dimmable. I dim to 40-60% during veg and steadily increase in bloom until full power is reached. Many believe veg can be very successful under reduced wattages. Another reason is heat, at full power my grow area temps go up fast.

 

[Hosebomber]

Hi Tead, You are missing a few things. The vegetative state does not require as much light to grow proper. Likewise, when you turn off the reds it helps reduce stretching in the veg state keeping internode length tighter and making more branches at a lower canopy height. Then there is the heat, power consumption, air exchange, and feeding levels that are all reduced.

 

[Tead]

I can sure understand the heat issues.
And yes... the Veg state does require less light, but if you're not burning your babies and don't care about power consumption, wouldn't more be better at all times?

 

[GrizzWald]

The suns spectrum changes with the seasons, this is what's trying to be replicated with different spectrums. The blues and longer hours to veg, then the reds and shorter days produce the flowers. I believe that some yellow/orange added for last four weeks of flowering could really help pack weight on led grows. ?.

 

[CO Finest]

With just one of my tents running all draws over 1500watts from the wall and puts out a ton of heat if all on for 18 hour during the hot azz days. So in veg mode I draw about 800 from wall with very low heat on during hot day times. That is one of my reasons. Heat,long hours,full power= burning your power supply out faster. If you do not care about cost then by all means but keep in mind the more red the more stretch and indoors not to good..

 

[Tead]

For the record... I do my growing in a VERY hot environment. I have an AC output going directly into my grow tent. My exterior temps are often above 100. Without the AC and with no lights on, my babies would cook very quickly.
Of course, since I'm running AC directly into the tent, so I'm less concerned about heat issues... but I've certainly battled them in the past.... thus explaining the AC into the tent.

To sum up what I've learned from this banter... a bit of stretching seems to be the only drawback (ignoring heat and power consumption).
The next natural question would seem to be "Do the plants grow faster or fuller when both spectrums are applied at all times during the grow?"
I don't have the gear to test the idea (multiple lights of the exact same design and a 2nd grow tent) so I'm afraid I can provide no actual data for this test.
Perhaps some day I'll want to answer this question enough to plunk down a major chunk of change for a 2nd setup.... but not today.

Thanks for you input all.

 

[Hosebomber]

They will not be as full because they will stretch more. But yes, IF you provide more light (up to the light saturation point) you will get more growth then with less power usage. The spectrum you give will depend on how much stretching they have and the amount of nutes they use.

 

[Srilania]

Actually, some of the reason for the ability to dim or shut some off has to to with wavelength creep. As LED's get heated, their wavelength can creep out of line from where they were put in. Many of the LED grow lights I've seen appears to have 1 blue and 1 red wavelength, so this would require the tolerances be tighter. Because of this, lowering the lights down puts less thermal creep in the light, and they keep to their tolerances.

 

[Hosebomber]

Srilania, wavelength creep as you call it has a very small window of 7-15nm max. If the diode is getting hot enough to cause much of a wavelength skew, it will be a very short lived panel and have thermal runaway well before the change in wavelength effects growth to any noticeable extent.

The dimming functions that some panels have is more of a power saving feature than anything else. Likewise, there are very few companies out there still claiming that you can use only 1 wavelength of red and blue each and have a successful grow.

 

[TomaHawKPT]

Hello,

This is my first grow, currently on week 3 of flowering, but still see no flowers but plant are looking healthy

I'm wondering if no flower visible is due to incorrect light settings. I'm using 2x TOP Led GrowLight 96x3w (Reflector LED grow light). These LED panels have two light switches, one for Growth and one for Bloom - is also possible to have both on at the same time.

I'm not sure how to set the lights during Flowering phase.

If I only set the Bloom lights on, it seems to have really low light intensity. Bloom setting only turns on Red lights, and as you can see from picture below, there aren't many of those.
If I set both Bloom and Growth lights on, all LED lights are turned on, more light intensity, but then also have Veg light spectrum.

What are your thoughts and experiences with the lights from TOP Led Grow Lights?

(photos from user IceMud)

Growth

Bloom

Both

Thanks

 

[Tead]

Howdy TomaHawKPT.
I have no experience with your lights. The only experience I have is based on much older lights.
Seems like your post would be better as a new thread in the Frequently Asked Questions forum section.
Having said that, your plants go into flower based on lighting time... not lighting type. The standard technique is to drop your lighting period from whatever you're currently running to 12hrs of light and 12hrs darkness.
Best of luck!

 

[CO Finest]

All top led light that have Veg and bloom witch's are full spectrum. The veg always has to be on for fans to works. The bloom switch is just a added red spectrum for flower stage of growth. The reason for having the bloom switch is during veg to much red will cause plants to stretch. The bloom switch does not turn on fans and will over heat power supply if only one turned on. Yes it is true it does save power when in veg only as well.

 

[Tead]

Wow... you mean that a company produces a light that can SO EASILY be overheated? Seems like a basic design flaw. <shaking head>
Hell... I can guarantee that I'd have a stoned moment and burn that bad boy right up.

 

[Srilania]

I kind of agree, it ought to have a thermal safety cutoff, or just run the fan on when the lights go, no matter where the switch goes.

 

[Hosebomber]

They will not overheat with only the bloom light on. The heat sink is large enough that if only the bloom diodes are on they will not reach a critical temperature. However, they are made to run bloom and veg on together for the proper spectra.

 

[TomaHawKPT]

Thank you all for your feedback.

So it seems I am doing the right thing then, as I'm using both Bloom and Growth lights on, and of course the 12h/12h lights schedule.

I had an issue with my lights time at the end of week 1/ beginning week 2 of bloom, and the lights were on for a bit longer than 24h... the timer went "kaput"... maybe that's why only now mid week 3 bloom I'm starting to see the first "flower hairs"

 

[browndirt]

As with mh and hps the hps also has veg state spectrum this is why when you switch from veg to bloom the plant continues to grow, LED is the same but has up to 12 spectrums compared to 2 with hps. If you need to control dimensions of the plant use less watts or be more strain specific. Use scrog and all control methods available. I find it better to use strains that have short stature 2 to 3 ft fimming pinching topping and manipulating the plant to fill an area with mostly just nuggets above the screen within a 2ftx2ft area utilizing a 4x8 grow tent with 8 sites dwc and running 2 Advanced Platinum Series p1200's expensive up front but last on average 200,000 hrs. and stay just warm to the touch, use just 1300 watts between the 2 and made in the U.S. When you turn on bloom switch and switch from 18/6 or what ever to 12/12 veg stage slows as most energy is directed to flower sites but the plant still continues to grow.