Light spectrum question

Im trying to make a decision on lighting for a micro grow 1ftx 3ft space. I’m using 4 23w 1500lm flouro. Most of all for the seedlings (if the bloody things germinate!) But whnt to know if I put a few more bulbs in the cabinet for both veg and flouro will it only effect the harvest ( and in what way) or does it impede the growth of the plant.


How can one tell what light spectrum is being emitted by a light.


How important is the spectrum of light to the grow.

The light spectrum is a pretty important aspect. In the vegetative state, you want color in the 6400k range. This looks like a bluish color. When flowering, you want to shoot for around 2700k, which is an orangish-red. These colors are to mimic the sun during the spring/summer and the fall, which just helps simulate nature.

The use of 6400k lights in the seedling and vegetative stages helps to limit stretch by the plant, keeping internodal spacing pretty tight. This is very important in microgrows, you don't want your plants to get out of hand.

I'm just finishing building my cabinet. My first set of lighting, which I will use from the time I put the seeds in the soil, until I use the HPS, is an array of 10 CFLs. There are seven 6400k CFLs and three 2700k CFLs. These are all 15w, so it's a total of 150w. I was going to go for all 6400k, but I decided that would be less natural, so I made it a little mixed spectrum.

For flowering, I've got a 150w HPS, which is more suited for flowering. If you're using HID bulbs, HPS is better for flowering and MH is better for vegging. MH lights also put out some UV light, which I believe increases the amount of THC or resin the plant produces, I'm not sure which.

I might actually leave the CFLs in there for the first week or so that I've got the HPS turned on for flowering. This should limit the initial flowering stretch, but I'm not sure. I just thought about that recently, I've got to look into it a little bit more before I do it.

And to answer your first question, a lot of CFLs will have the light spectrum printed on the base of the bulb if you're still unsure. It will just be a number, such as 6400k, 2700k, something like that.



Here's a chart showing chlorophyll activity, you can see it peaks around 2400k and 2750k for the red spectrum, and 5650k and 6200k in the blue spectrum. Remember, blue for vegging, red for flowering.

Good luck with your grow!

thank you

I use daylight or sunlight spectrum fluoros (approx 6500K) for vegging and warm or soft spectrum fluoros (2700-3000K) for flowering.

Thank you bounty29. Very useful information.

light sectrum is not neccecarily needed. but if you want to go the extra mile all the power to you. when plant's are stretching in bloom they are not aware that they can possibly stetch in to their light source. (they think it's mile's up) so they will stretch into the light. but if it ever come's to this stetchy flowering shoot's are'nt as flexible as veg shoot's. so no point in trying to bend them. just grab a good area of the stem and crimp it with youir finger's. the shoot above will fall over limp for a day. then come back alot stronger than it was before ready to support some good weight. it will only slow the stretch for a day but when it heal's it will be alot lower than it was before being pinched.

Hello,

the right light spectrum is very important for healthy, tasty and high-yielding plants. One can take a look at specification papers which often contain spectrum plots. One can collimate light using a tube of white paper and refract it by two CDs. One can pluck some flowers and see them in the artificial light.

The picture shown by Bounty contains some mistakes and sloppy philosophies: Photosynthetic activity differs a lot from light absorption. Most efficient is an even spectrum containing all colors including lots of green. It is an urban myth even told by some academics that green light was a waste. Furthermore "light temperature" (Kelvin values, k) is defined with white noise (colorless). Its average wavelength describes a monochromatic (fully colored) light.

Remember, blue for vegging, red for flowering.

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This is an electronic / commercial myth. In my opinion switching the type and amount of lights just stresses the plant.

You probably have light of "warmwhite" "three-bands" quality, Pollen. You could add "full-spectrum" or "daylight" fluoros and incandescents. Depending on the height of your chamber you may use a HID light. Stick your nose around, experiment a lot and stay safe!

FYI, males should be kept and allowed to spill pollen for some time. Early pollination surely refreshes the females, makes them bud faster and better and prevents hermaphrodism which can taint a nearly done crop.

Uli

First off, do NOT keep males, unless you want a harvest full of seeds. I don't think anyone here wants that, except those guys over in the breeders forum.

I think there is plenty of evidence that blue for vegging results in tighter internodes, and red iis better for flowering. It mimics nature, which is where weed grows best. The green light "urban myth", do you have some facts to back that up with?

I've seen many people that use green light during the dark period, and it does not harm the plants at all. This means the plants don't "see" green. Why would you want a lot of it? The reason plants look green to us is because that's the color of light they reflect. Why give it more of something it's just going to reflect?

I'd rather cull males asap and have a seedless crop and take my chances on them going hermie, and be able to do something about it (plucking pollen sacks if feasable, cutting off budsites with hermie-traits) then having the whole plant get seeded from the start.

I don't mean to sound negative, but unless you have some facts to backup all these claims, I don't believe them one bit.

Edit: And I missed this the first time, but did you really just suggest using incandescent lights?

bounty29 said:

First off, do NOT keep males, unless you want a harvest full of seeds. I don't think anyone here wants that, except those guys over in the breeders forum.

I think there is plenty of evidence that blue for vegging results in tighter internodes, and red iis better for flowering. It mimics nature, which is where weed grows best. The green light "urban myth", do you have some facts to back that up with?

I've seen many people that use green light during the dark period, and it does not harm the plants at all. This means the plants don't "see" green. Why would you want a lot of it? The reason plants look green to us is because that's the color of light they reflect. Why give it more of something it's just going to reflect?

I'd rather cull males asap and have a seedless crop and take my chances on them going hermie, and be able to do something about it (plucking pollen sacks if feasable, cutting off budsites with hermie-traits) then having the whole plant get seeded from the start.

I don't mean to sound negative, but unless you have some facts to backup all these claims, I don't believe them one bit.

Edit: And I missed this the first time, but did you really just suggest using incandescent lights?

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I'm in 100% agreement with you here Bounty. Males should be disposed of ASAP unless you want a whole buncha seeds and green light (and most incandescent lights) produce spectrums that are simply unusuable by cannabis. Its been proven 10,000 times over that the blue spectrum promotes good stem and leaf growth and the red spectrum promotes good bud growth.

I tried growing with incandesents one time in my life (was probably 15 at the time I think) and the whole thing was a total disaster. They simply do not put off the necessary spectrum or the necessary quanity of light for decent plant growth.

I'm not trying to flame you here Grasso but...seriously...

Hello,

no, males do not need to be disposed as soon as possible. The life cycle of a male is shorter than that of a female hence males are harvested a month or two earlier than females. Their leaves can be made into cannabis oil. Their flowers can be cooked and eaten.

The chart given by Bounty contains even more mistakes of the wishful-thinking illusion-pitch or should I say messed-up kind. In my gallery you can find more rational charts, although some of them are not properly scaled and dimensioned either. Claims are made all the time, and some of them turn out to be wrong.

A spectrum containing lots of green light is most important to plants. Growing plants under sodium light is a border-line case. Nothing beats growing them on the window sill and outdoors because a leaf absorbs nearly 10 % of all green light (not 3 % as Bounty's picture tells, as there are Chlorophyll A and B) and transfers it to electrical and chemical energy with an efficiency of one third. The 90 percents reflected off or let through this leaf can be used by other leaves. Blue and red light are absorbed sooner than green light but transformed mostly into heat say used with an efficiency of only one tenth. Botanical fluorescence means that some of the energy of absorbed blue light is emitted as red light, in explanation frequency of light waves is shifted, so-to-say for second-hand use.

Nobody advises to use *solely* incandescents, Mr. Micro. Salt alone does not make bread; yeast alone does not make bread; flour alone does not make bread; water alone does not make bread; heat alone does not make bread. Only the conjunction of these ingredients makes bread.

Uli

Grasso said:

Hello,

no, males do not need to be disposed as soon as possible. The life cycle of a male is shorter than that of a female hence males are harvested a month or two earlier than females. Their leaves can be made into cannabis oil. Their flowers can be cooked and eaten.

The chart given by Bounty contains even more mistakes of the wishful-thinking illusion-pitch or should I say messed-up kind. In my gallery you can find more rational charts, although some of them are not properly scaled and dimensioned either. Claims are made all the time, and some of them turn out to be wrong.

A spectrum containing lots of green light is most important to plants. Growing plants under sodium light is a border-line case. Nothing beats growing them on the window sill and outdoors because a leaf absorbs nearly 10 % of all green light (not 3 % as Bounty's picture tells, as there are Chlorophyll A and B) and transfers it to electrical and chemical energy with an efficiency of one third. The 90 percents reflected off or let through this leaf can be used by other leaves. Blue and red light are absorbed sooner than green light but transformed mostly into heat say used with an efficiency of only one tenth. Botanical fluorescence means that some of the energy of absorbed blue light is emitted as red light, in explanation frequency of light waves is shifted, so-to-say for second-hand use.

Nobody advises to use *solely* incandescents, Mr. Micro. Salt alone does not make bread; yeast alone does not make bread; flour alone does not make bread; water alone does not make bread; heat alone does not make bread. Only the conjunction of these ingredients makes bread.

Uli

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Green light? No unless you wanna maybe see your plants while the light cycle is sopposed to be off.

Look at it this way, put green in their with your other red or blue lights and you will notice no difference. Put green in their alone and you will notice no plants. Because plants reflect green light. EVEN if they absorb some of the green light its not enough to make a meaningful difference!

Ohh, and yes herb plants do well in a window seal. It's because the Sun is about 1 billion times brighter then anything we humans can construct. Even diffuse light from a window is usually brighter then most floros, halogens & incandecents

that's a chart for hps lights....so you can imagine how much smaller the penetration is on your flouros. keep those lights as close as possibly

Consider this about indoor growing, optimal light is probably best attained via combination of lamps. Don't think all the best factors of the sun are in a single humble light bulb.

those green lights are used to check on the plants at night....thats why they sell them in nurseuries for.

incondescent bulbs dont do crap..ive tried it and it is garbage...putting it in a window is ok if thats your only option...good for stating seeds i guess...but if you do it the whole time youll get a plant like this..this was taken the first day i got these lights...see how skimpy and sad that plantr is? almost nothing for yeild either...maybe a 1/4 ounce if i was lucky (didnt have a scale)

Haiya,

yesterday I bake a cake but it did not raise and it tasted like shit. I conclude that ovens are rubbish. Ovens produce disgusting cakes, so I will never touch an oven again! Ovens, green light, incandescents and staminate plants are all useless. Irony off, the moral of the story is that one should not create a scapegoat for one's own mistakes.

Greetings,
Uli