Full spectrum T5 vs. Red/blue LED

[Shadeflower]

Originally Posted by Ray

Plants use the entire visible spectrum and then some.

Red/blue (often called "blurple") LEDs came into being when folks were illegally growing pot. The "criminals" were often caught by monitoring residential electric consumption.

The energy consumption is lower with LEDs than any other form of artificial lighting, and by concentrating the energy to the absorption peaks of chlorophyll, they were able to reduce it even more, in an attempt to evade the authorities.

Blurple LEDs work. A full-spectrum LED strip works better. Plants look alien under them - something a pot grower couldn't give a crap about, but an orchid grower might.

complete and utter nonsense.

Red and blue led's were primarily produced by the marine fish industry and the fact that the red and blue diodes were the cheapest LED's to produce out of all colors. They knew lights needed more than just blue and red but they claimed that is all plants needed and their lights were engineered to be the most efficient.

Did pot growers have anything to do with LED's getting developed? Certainly not lol.

Is red+ blue enough for plants? No they need full spectrum, red + blue does not provide all they need.

Is red + blue energy efficient? Yes use it to supplement sunlight which is already providing full spectrum and a red + blue light will be the most efficient additional ennergy you can provide.

red + blue comparrison to Full sprectrum:

White LED vs Red Blue White LED Grow Test w/Time Lapse - Lettuce Ep.1 - YouTube

[camille1585]

Originally Posted by Shadeflower

Is red+ blue enough for plants? No they need full spectrum, red + blue does not provide all they need.

Is red + blue energy efficient? Yes use it to supplement sunlight which is already providing full spectrum and a red + blue light will be the most efficient additional ennergy you can provide.

I have to disagree and this is incorrect or at the very least incomplete. Plants CAN be grown well solely under Red+Blue only. It is a bit dangerous to make such broad claims on the basis of one video, one where we don't even know all the details of this small scale test and represents 1 test on 1 crop species. And, if you were to watch the other video in the same channel which repeats the trial with soybean, you would see that he comes to the opposite conclusions.


I would also like to make a few points to correct this statement.

1) Nearly everything can be grown under a Blue+Red spectrum, oftentimes very well. These include leafy greens, herbs, tomatoes, cucumbers, peppers, orchids and many types of field grown crops.

2) The type of light isn't the only thing to consider. The ratio of blue to red will also have some very strong effects, also depending on the crops. For instance in your lettuce video, if the fixture he used has a relatively high proportion of blue then the plants will have more compact growth and lower fresh weight. If he had measured the plant dry weight, he may have found that the Blue+Red grown plants had produced more dry biomass. Generally in lettuce, the higher the proportion of red, the more fresh weight you get, but the trade off is often lower dry weight which translates to shorter shelf life. I can also tell you that soybean (keeping to the example videos) reacts more favorably to extra blue light.

3) While plants do use other wavelengths of the spectrum their impact on yield and development can be minor. The only other wavelengths that I would agree are often important would be those in the far red range, because of the very strong effects these have on plant physiology.

[Orchidtinkerer]

camille, I have to disagree and I think I can safely make such broad claims - if it helps people who have never grown under LED's before.
You mention the second video. Even in the second video you will notice that the plants you claim turned out superior did not grow right and the taste well look at his face when he eats it.
You seem to want to defend blue+red lights, that makes me believe you want to justify your use of them and can't justify getting a better light. That is fine, but the evidence is indesputable. If you wish to dispute it you are achieving nothing but to confuse people.

I know you think you are doing it because you think I or the person making that video doesn't know better.

The only way to know better is to try. I have, he has, you want to justify that red+blue works just as well.

If you finish the second video after noticing that the cheap amazon light did actually only produce 50g of beans vs the 70 grams on the weirdly grown red+blue plants he then compares it to a decent full spectrum (not cheap chinese rubbish from amazon) and the plants produce 80 grams.

So what was your argument, watch the second video? I did.

So yes he was able to change the parameters but his findings are in line with my findings and more people are discovering it every year. It's a slow process, I know I was one of the pioneers to try out LED's when they first came out. Still have my very first unit. Big chunky thing, was top of the line back then. It's no comparrison to a full spectrum.

Ideally he should include a plant grown unde sunlight to add to his test but hey that is something for you to show us camille.

Instead I know you will just disagree again without actually trying to prove me wrong with practical proof but that is fine. I know full spectrum produces far better growth than red+blue ever can and if people don't want to believe that because red+blue units are cheaper then I won't stop anyone using a red+blue unit. Personally I cannot stand looking at the the light they produce.