stiffnuts12
Well-Known Member
Is there much of a difference in growth when using a veg led over a full spectrum? What's the advantages of a veg light?
Veg led vs full spectrum
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UpstateRecGrower
Well-Known Member
No, but in bloom you’ll be better suited with a bloom only light (3000k)
Yes, there is a significant difference.
Veg lights have a lot of blue in their spectrum. Blue light inhabits cell expansion so plants grow with a veg light will tent to be short and compact with short internodal space (buds are closer together and colas are more dense). When it comes to flowering, that works against the grower. Research by Bugbee states that, in their testing, plant yield was reduced by 0.77% for every % of blue light between 4 and 20%.
If you're using a veg (blue) light, you'll need to switch to a full spectrum or flower light once the plants start in the flowering stage. With very little blue in the spectrum, a red-heavy flower light will cause significant growth and it's more energy efficient.
The downside to having both a very light and flower light is the cost of the lights and the labor to switch them out (once per grow). On the other hand, plants won't be tall and gangly and they will tend to produce more flower at a lower electricity cost.
A "full spectrum" light has a range of light colors ranging from blue to red and, in some lights, UV and/or IR. A true full cycle light means that you only need one fixture but it's a compromise because you have blue photons, which tend to reduce yield, plus blue photons that do not result in as much photosynthesis per KwH. Electricity costs will be higher and yield will be lower than with separate veg and flower lights, but they're cheaper to purchase and there's no cost of switching lights like you have with seperate lights.
Most growers go with a "full cycle" light but some growers are happy with flower-only lights like those from HLG and Chilled, sometimes supplementing the flower light with a small blue led.
Horselover fat
Well-Known Member
Yes, but I'm not sure it's that simple. You may be able to cram more tops in the same space if the plants are more compact.
In a video by him that i watched, it came across as it doesn't make much difference.
skip to 14 mins
@OP i am currently flowering an Auto in my veg tent (4000k), its only 2 weeks into flower but its looking fine to me
Horselover fat
Well-Known Member
I can't remember the video he talked about these findings, but this is from their study:
Cannabis lighting: Decreasing blue photon fraction increases yield but efficacy is more important for cost effective production of cannabinoids
LED technology facilitates a range of spectral quality, which can be used to optimize photosynthesis, plant shape and secondary metabolism. We conducted three studies to investigate the effect of blue photon fraction on yield and quality of medical hemp. Conditions were varied among studies to...
Not a huge difference, but a difference anyhow.
Thanks for posting the details - a 12% drop in yield due to a 16% increase in blue is a drop in yield of 0.75% per 1% increase in blue photons not 0.77%.I can't remember the video he talked about these findings, but this is from their study:
Cannabis lighting: Decreasing blue photon fraction increases yield but efficacy is more important for cost effective production of cannabinoids
LED technology facilitates a range of spectral quality, which can be used to optimize photosynthesis, plant shape and secondary metabolism. We conducted three studies to investigate the effect of blue photon fraction on yield and quality of medical hemp. Conditions were varied among studies to...journals.plos.org
Not a huge difference, but a difference anyhow.
A 10% decrease in yield, for example, means I get 20 ounces instead of 22 ounces. A commercial grower won't be too happy with that. Granted, some of the variable costs will drop but a 10% loss in yield means a 10% drop in income.
stiffnuts12
Well-Known Member
Well I have the chilled growcraft 6x600 watt led was thinking about getting the chilled mini for veg just not 100% on it just yet
I think the X6 Mini is a great light! I have an X2 veg and an X3 for flower but I would have bought the Mini if it had been on the market when I bought my lights. The uniformity is amazing.
Are you running out of height in the grow area/tent? A veg light will result in shorter plants
Are you buds/colas dense? Though blue light decreases yield Bugbee has said, and I don't recall which video it was, that blue light will produce denser buds.
Captain Obvious chimes in - if you've got the X6, that tells me that you're in at least a 4' x 4' which means that the X6 Mini will give you coverage only in the center 2' x 4' portion of the grow area. Are you thinking of moving plants to the center in veg and then spreading them out of flower?
Two photos from day 38 of my current grow of Strawberry Pie autos. When I went to top the plants at day 21, the foliage was so thick that I had a hard time being able to count the nodes. I haven't finished a grow using the X2 as a veg light but, after 22 days under the X3 flower light, the foliage at the top is still very thick. The plants were 17" tall in the first photo and 47" in the second photo - 30" in 22 days is pretty crazy.
stiffnuts12
Well-Known Member
Have a 5x5 area in my basement I want to veg in. I would like to keep the areas separate. I have the chilled x6 and a hlg 600 rspec in my current room
And nary a blue photon to be found!
If you're setting up a veg area, you've got to light it with something. Seeing that you're already using Growcraft there's some logic in keeping it all in the family.
OTOH, why not use an HLG veg light? There's a cost savings but there's a reason for that - check the PPFD maps here. Check the map for an HLG light and then check the map for the X3. Board lights cost less but their uniformity leaves something to be desired.
The X6 Mini competes with the Spider SE 7000 for uniformity (almost).
stiffnuts12
Well-Known Member
I like chilled over hlg. Don't get me wrong hlg is good and what I started out with. Nut st this point saving money is nice as well
I hear ya - I started with a Mars SP 3000, then got the X3 flower, I added a little Vipar Spectra XS-1500 to take care of some branches that "fell" out of my tent, and then picked up the X2 when it was on sale this Summer.
"saving money" - the X6 Mini is $649 but you can find discount codes that will knock off 5%. That's still >$600 which is at the high end of the 2' x 4' market - the HLG is about ½ that price, right? With the HLG, you'll still get the benefit of having a veg light but you'll have to deal with the hot spot.
stiffnuts12
Well-Known Member
The chilled x3 mini will dod a 3x3 for $400 isn't all that bad. Can text it out and see if it's worth it I guess
Horselover fat
Well-Known Member
Yes, but the reduction in yield is due to more compact growth. It may be possible to counter that by having more plants/tops for the same area.
grotbags
Well-Known Member
on the whole the terms "veg spectrum" and "full spectrum" are meaningless buzz words used by led light manufactures to sell lights.
their is no standard manufactures use for what a "veg", "flowering" or "full spectrum" should look like so everyone just makes it up as they go along.
almost all manufactures "veg" lights are at best simply normal white 70/80cri 5000k diodes that they use for their "full spectrum" or "flower" lights without the added 660nm red diodes, at worst they swap the red 660nm monos for more blue 450nm monos (bad idea).
their is more than enough blue in nearly all "flowering" and "full spectrum" led lights for vegging, you will probably notice worse growth under a dedicated "veg" spectrum than "standard", "flowering" or "full spectrum" lights.
Grow Lights Australia
Well-Known Member
This is correct. A good spectrum is a good spectrum and will veg and flower faster than a heavy blue spectrum. It is a bit of myth that you need more blue light during veg. The term "full spectrum" is also overused in this industry. A full PAR spectrum should run from at least 400-700nm. An extended PAR spectrum should go beyond 700nm into the Far Red range. Very few LED lights on the market have light below 430nm so they miss out on the Violet end of the spectrum which counters cell expansion (stretch). A small amount of UVA can also induce more root growth for propagation so is desirable for all stages of growth, just like you find in sunlight throughout the year. We don't sell a "veg light" but we do sell a propagation/leafy green light that has a little more blue in it mainly to thicken the epidermis in leafy greens and boost root propagation in clones and seedlings.
shotnva777
Well-Known Member
I know this is an old post, but I'm new to LEDs and I have a question! I was researching some things and came across this post. Seems like some knowledge In here, so here goes nothing.
It seems that nowadays most LEDS are made with a full spectrum of different colored lights, with no ability to switch certain colored leds on and off. Most have a dimmer, but other than that, all the different colors, UV and IR's just stay on, the whole way through the grow. I've only seen a small percentage that offers that type of versatility... Sayhon's SH2000 unit comes to mind, with a UV/IR supplement switch, that cuts them on and off at will. BUT, then again, I'm also not looking at super expensive grow lights!
My particular upgraded China light is 240w; it's basically two 12x12" quantum panels, bolted together with a reflective hood. Together, they are loaded with 360pc of 3500k "sunlight" leds, 200pc of purple leds, and 16pc of UV leds - for a grand total of 576 LEDs across both boards... Each panel has its own driver and has a "bloom booster" switch. The problem is you only get access to the purple and UV leds through the bloom booster, which I was under the assumption only was used during flower.
But since every LED distributor is using them all together now anyways, would I be better just having all 500+ LEDS cranking at once? Or will that not be as effective as the pure sunlight spectrum during veg? I'm so used to MH and HPS, this is all so confusing..... thanks for any input!!!!
(I've attached photos of my grow lights specs and the Sayhon unit i was referring to!)
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i am doing pretty well with 8 household leds. 6 4000-4500k and 2 6500k for veg . they are 14w leds and the total real wattage is 114 watts im vegging under these 5 plants in 5l pots. im in week 3 and they are a good 25 cm high with super short internodals 1-3 cm and i have lots of future colas.
you want the correct ppfd for each stage of growth. forget about uv and purple; use the correct potency of light for each stage, if it where me i would veg without the purples and uv and only use it to give that extra umph in weeks 6 7 8 9 of flo
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