What do different coloured lights do??

Spectrum effects results but Spectrum is not visible color; meaning that the color that effect you're plants hormones won't be visible. even if the cheap LED claims its red spectrum because its light bulbs are red doesn't mean its true.

To answer your question technically if we aren't just talking about color and we are talking about spectrum then blue light tends to help vegging and tends to be softer on plants, red light tends to cause flowering. Green light is reflected by the plant, that why it's green, and white light is probably just some stand house bulb that has a hurtful spectrum to plants.

 

When growing you want both red and blue during both veg and flower. the more spectrums of light the healthier the plants will be, this is true regardless of strain from what ive learned. Green is useless, as the guy above me said its just reflected off the plants.

Different colored leaves are a result of the strain and theres not much you can do to affect this, though sometimes you can get them to turn purple by letting them get a little to cold (50 degrees or so) For good colorful strains try anything with purple or blue in the name (blueberry, purple urkle, ect). I'd love some rep up if u liked my answer

 

Plants are "blind" to green light. They are used when entering a room during a dark period.

 

I was wondering about that. Someone told me no, dont even let green light on your plants during a dark period, as it will still screw them up during flower. So it's good then? I can have a green light on during the dark period of 12/12 and not mess them up?

 

Yes. I use one when harvesting plants in the dark.

 

All of the lights you have are probably useless for growing.

As far as spectra goes it's best to have the entire photosynthetic spectrum. It's also false to say that green is totally useless. It has very very little impact on anything, but it does have some. Green light is not 100% reflected, a little bit of it is absorbed and used by the plant for photosynthesis, just not very much. Plants can also use a higher percentage of green spectrum if they have reached their blue light saturation point. Each wavelength or small sets of wavelengths cause different reactions in plants.

Some blue light responses are chloroplast movement and stomatal conductance. One red light response is stem elongation.

There are also responses to varying ratios of certain wavelengths. The red to infrared ratio is a significant one. Any grower knows how stretchy stems get when they are buried underneath a lot of foliage and are not exposed to any direct light. Most probably don't know what the cause of this is though. Of course the reason is that those stems elongate in order to try and reach better light, but the actual cause of that elongation is the ratio of red to infrared light. Much more infrared light passes through leaves than red spectrum does. If you shine a light through a leaf's surface, the light that exits the leaf has a much higher ratio of infrared to red because the leaf absorbed most of the red light. Plants respond to this high ratio by elongating stems. Most plants do this. It's a natural evolutionary survival mechanism to let plants buried under forest canopies stretch and poke though the canopy to get good usable light.

That's just the tip of the iceberg when it comes to spectral plant responses. There is a lot that is still unknown but more research is done all the time and the picture is beginning to become clearer.

 

I do understand that not all green light is usless. That is why you shouldn't work in your room during its sleep using light from a green bulb, no matter what jorge C says.
I was trying to make a simple answer for a change.

 

If you wave them in front of someone's face when they're on drugs it'll make them hella trip.

 

My post was just a general response. It wasn't aimed at you directly. I usually just say green is useless also, for simplicity's sake. Wasn't implying that you didn't already know that.