Effects of differing wavelengths of light on cana growth.

[Randalizer]

I dont know how expensive t12s are, but t5s dont seem super expensive to me .

4 foot T12's are about a couple bucks each. Depends on what quantity you buy them in. Lumen output varies but around 2950–3600.

I think T5s are fine lights and fill a nice in between spectrum between cheapie T12s and HIDs. Again, it's all about what your space can handle and what you can afford.

Edited June 29, 2010 by Randalizer

[cache37uk]

Just goes to show how we all live and learn. I'm expecting to harvest 5x jock horror this weekend. Flowered entirely under 12/12 400W HPS, goddamit i wish i'd read this thread a couple of weeks ago, i'da tried switching bach to the 400w MH for the final two weeks. On the bright side their looking really good and sparkly.

Amazing thread to read, thankyou one and all.

[Grow1]

From an evolutionary stand point, canna's stretchy growth for 1) may be due to that emf range (infra red to yellow) being able to better penetrated foliage. when a canna plant senses these wavelengths, it knows to stretch so that it can get to the light. And perhaps it get stocky from blue light as that is what it sees when the plants sees blue sky? This telling it not to stretch so much, perhaps because open sky has more wind that may snap branches?

would not bluer light indicate to the plant that it was 'springtime' and cause it to want to grow quickly and bushily (to provide most branch space for flower nodes to grow). In nature this would be true because the plants are lighted with the sun, which is slightly bluer due to the tilt of the earth. Then conversely when it is 'autumntime' the tilt of the earth away from the sun means a slightly redder light spectrum. We can see this colour change in extreme form at sunset when the light has more atmosphere to travel through. So when the earth is tilted towards the sun in the spring there is slightly less atmosphere so bluer light. During autumn (the end of most natural flowering in the wild) the plant would naturally stretch to try and gain more light. Red light has less energy than blue light.

Because the energy of electromagnetic radiation (i.e., the photon) is inversely proportional to the wavelength, red light (longest in wavelength) is the lowest in energy. As wavelengths contract toward the blue end of the visible region of the electromagnetic spectrum, the frequencies and energies of colors steadily increase.

now this may seem wierd.. HPS is red so the spectrum looks more red shifted which indicates the light source is moving away so plant steches out to get closer to it... and blue means the light source is comming closer so kinda squats down.... or maybe this smoke is better than i thought

I don't think red light always indicates red shift, but it may indicate the approach of autumn for the reasons I have outlined above.

Im sure in cannabis and other fruits and veg that the red and far red ight is a trigger for more long term seasonal changes in the plant such as budding in autumn (which is a very red season) to produce seed for the coming winter. But im also sure that the blue light can help force plants to stay squat by mimicking the light recieved at the top of a canopy.

Perhaps the bluer light also makes the plant think it is in spring so time to bush out ready for flowering?

[Randalizer]

would not bluer light indicate to the plant that it was 'springtime' and cause it to want to grow quickly and bushily (to provide most branch space for flower nodes to grow).

Looks good on paper but in practice, blue light makes cannabis grow bushy/stout and slowly, where as orange/red light makes cannabis stretch and grow quickly.

Perhaps the bluer light also makes the plant think it is in spring so time to bush out ready for flowering?

That makes no sense at all as cannabis flowers in the fall, except for autoflowering types.

Edited September 21, 2010 by Randalizer

[groovelick]

I wonder if the diff colours of light effect the root mass differently as different photochemicals would be produced, ie red photochemicals give you strech, and blue bushyness I wonder if there is a colour that gives whopp off roots?

[Randalizer]

I think I've read somewhere that cannabis roots were sensitive to uv.

[groovelick]

The bit about photochemicals makes sense then cause diff wavelengths would produce diff chemicals (using chemical to cover hormones as well)

[Randalizer]

I think this is covered somewhere deep in this topic, but I believe I read that the theory was that when UV reaches the roots (being more energetic and able to penetrate more deeply) the plant goes into a squat bushy mode (for the strains that can do this) to protect the roots.

Hence why mountainous strains are squat and jungle strains are lanky.

Edited September 22, 2010 by Randalizer

[NattyFido2]

Just my 2p worth.

As far as I understand, red light such as from a HPS penetrates the foliage and causes stretch so that the growing tips can reach the canopy. Blue light as from a MH signals to the plant that it is at the canopy and can concentrate its energy on growing foliage instead of stretching.

As for the UV, I thought that the reason cannabis produced the resin we all crave was to protect itself from UV rays. So if you give the plant more UV, you get more resin as it tries to protect itself.

One last thing, if an object looks green (for example a leaf), that is because it is reflecting the green part of the spectrum and absorbing the other colours ie. red and blue. So green plants absorb very little, if any, green light.

[Randalizer]

As for the UV, I thought that the reason cannabis produced the resin we all crave was to protect itself from UV rays. So if you give the plant more UV, you get more resin as it tries to protect itself.

One last thing, if an object looks green (for example a leaf), that is because it is reflecting the green part of the spectrum and absorbing the other colours ie. red and blue. So green plants absorb very little, if any, green light.

While a plant more produce more resin to protect itself from UV, there is a limit to how much it can produce I would think. That being set by genetics as well as environmental factors.

The green light not being absorbed is well known to many of us. I use a green light as a work light during flowering (since the plants don't respond to it as well as full spectrum light). This is also mentioned earlier in this topic. In fact near the very first few posts.

[NiKEUS]

Philips CMH + Phillips SON T (in a cool tube) + UVB + psychosis cuts in a DR80(damn lack of space)

the spectrum of the CMH really caught my eye on another forum and I have to say I'm impressed with results so far, when i switched to flower i added a 400w hps in a cool tube and started to defoliate after switching (before the discussion drops on defoliation... I prune I don't remove all leaves just a fair chunk of fan leaves.) The reason I mention defoliation is... the mention of yellow light and penetration, that's got me thinking .

I found that I had some of the most healthy looking plants from CMH, I have friends who use just HPS and ones that use dual specs, all our plants look completely different for the same strain even down to how the texture of the leaf is.

In the final 3 weeks I'm going to add UVB CFL's to my grow for 30 minutes expanding to 90 minutes towards the cull.

The reason I went to CMH was simply it replicated the sun closer than any other bulb that is affordable... plasma looked promising in theory but its expensive and I'll wait to see when the verdict is in about them.

LED I think should be used just for supplementation until better penetration appears and better spread (there is some guy selling ones that I saw with 4 or 5 different specific wavelengths that seemed impressive) also there are 2w (and 3w i think if i remember rightly) led bulbs that have better penetration but are not as robust, better spectrum spread and the specific colours from LED seem like a good idea to me .

[jason24msc]

Hi everyone,

There are genes in the plant which are turned on by red light or blue light. The blue light is a higher frequency and energy range so it has the ability to penetrate the canopy better than redlight. When the plant senses blue light (using cytochrome, I think) a gene is expressed which tells the plant to stretch. The plant stretches to get to the main source of light where there is an abundance of light in all frequencies (red through to blue). Once the plant senses the red light it knows it has got through the canopy because red light cannot penetrate a heavy canopy (due to its lower frequency and energy level). In these sections of the plant the red light triggers a gene to be expressed which promotes shoot and foliage growth, to maximise the surface area which is available to capture photons and begin photosynthesis of the plants main energy requirement, Glucose, which amongst other things is used to make the cell walls of the plant.

I know this cos I learnt this in plant science at undergrad level in 2007. No references though, but google should tell you more.

Edited October 8, 2010 by jason24msc

[Randalizer]

I know this cos I learnt this in plant science at undergrad level in 2007. No references though, but google should tell you more.

I think this is some what strain specific?

[jason24msc]

I think this is some what strain specific?

The results I saw were done with peas and I think most likely arabidopsis too. I would imagine that the fundamental response for red and blue light within the genes is the same for all plants.

Cucumbers and humans share like 90 percent of their DNA. So chances are that different strains share similar genetic features.

[NiKEUS]

Cucumbers and humans share like 90 percent of their DNA. So chances are that different strains share similar genetic features.

I saw a film once where a girl shared 100% of her dna with a cucumber I read somewhere apparently that we share 50% dna with banana's...

any way it has been documented by a fair few growers that, hps causes more stretch than mh, I think that's common knowledge.

Perhaps with blue light the plant stretches outwards more than upwards.