A question for DIY LED!!! please!

In this time....is lot of diy led .....but ...CREE CXA??? 3070??? 3090??? white light? or yellow??

Why not blur and red????? isn't that better????

Yeeep. Blue n red are the spectrums used. However you can use the Kelvin scale for white lights. Just follow the typical cfl Kelvin values

White power is the answer. Red vs blue is old hat and long disproven. Much cxb3590 many hlg-185h, very diy

There are lots of threads to help along your journey

What kind of results would 750 PPFD blurple provide?

Are the lack of examples due to a lack of high efficiency blurple lamps, or just that blurple is no good? Is the advancement of cob usage due to it's superior photosynthetic absorption, or just that they are 10 times easier to mount and wire in a high wattage package?

Rahz said:

Is the advancement of cob usage due to it's superior photosynthetic absorption, or just that they are 10 times easier to mount and wire in a high wattage package?

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I would like to answer this portion of your question with D) All of the above.

How do we know white light is more efficient for plant growth? I mean, it's not exactly fair to compare cobs with Mars or Apollo.

Wow...... do some research. You get the right spectrums from cobs without the visible to us blue and red. The plants care for photons not lumens. Cobs are better for penetration and efficiency. 3w diodes vs 100w cobs hmm mm who is gonna win. You can grow weed with blurple but better weed with cobs

What is the right spectrum and who said anything about lumens? If there's some truth to a balanced full spectrum light source being better than red/blue it's going to come in the form of empirical data, not opinions. It's clear that blurple hasn't captured the market but I'm questioning why that is rather than assuming cobs are better because they're popular at the moment. Total cob efficiency depends on the emission of blue light. This is apparent when we start seeing the notable drop in efficiency at 2700K so it's not clear that red shifted blue light is more efficient than producing it through the band gap.

I got slightly off my point. Cobs contain red and blue wavelengths. Without being visibly coloured. I don't fully understand most of the jargon. What I have gathered is that cobs give off the correct spectrums that we are looking for. With a higher intensity. Red and blue does work. Just not as efficiently. There are plenty of people here doing the research and providing data.

Surely the proof is in the pudding as such. There are some good numbers being pulled with cobs. Better than I have seen with blurple lights. Not discrediting blurple as it has been working for a few years now. Tbh from everything I have read it seems that 3000-4000k is performing. Sure 3500k seems to be the sweet spot for an all the way through light. Time will tell.

Just read my last post. Was a bit rude. Apologies

Rahz said:

What is the right spectrum and who said anything about lumens? If there's some truth to a balanced full spectrum light source being better than red/blue it's going to come in the form of empirical data, not opinions. It's clear that blurple hasn't captured the market but I'm questioning why that is rather than assuming cobs are better because they're popular at the moment. Total cob efficiency depends on the emission of blue light. This is apparent when we start seeing the notable drop in efficiency at 2700K so it's not clear that red shifted blue light is more efficient than producing it through the band gap.

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There's a few chips that are full spectrum. But of your shopping by nm then 440 465 470 blue, 660ish red. Its not too crucial. Iv been looking for a uvb chip to add with no luck.

The chips have a cool lense attachment you can get to spread light out pretty efficiently.

Blurple would resemble nighttime light refractions I think. Do us an experiment! Build a 500w blurple only haha.

It's not Blurple in the real world, why would you want it?

Its not just a mix of blue and violet LEDs?

iHearAll said:

Its not just a mix of blue and violet LEDs?

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No, white is a distribution of all visible nm from 400-700nm. If white light is really white, its called cool white and have more blue. If it is more yellow it called warm white and have more red.

Meant blurple haha. It just seems like a red/blue LED grow light with the addition if purples to blend it all. I'll do some research

You don't need a high efficiency blurple to discredit it's effectiveness in yielding buds. You could figure this out using low efficiency blurple panels as long as you had control over ppfd and intensity.

I suspect that the 3000k 80cri spectrum will still produce better yield than any blurple simply because blurple lacks in amber. Even if the ppfd in both environments are equivalent, I still suspect that the light containing ample amounts of amber will win over one that contains little to no amber.

In other words, I'm very suspect of the blurple spectrum, not just efficiency. Too much 660nm produces short plants, but reduces yield in flowering, and increases flowering time.

Amber is the key, which is one of the reasons why I think the HPS spectrum is so good. More amber means more stretch, better penetration, and lower %Pfr throughout the plant.

I use mostly COBs currently. But when I go into outer space with Matt Damon, these are the blurple lights we are going to use for the first grow room on Mars.

Rahz said:

What kind of results would 750 PPFD blurple provide?

Are the lack of examples due to a lack of high efficiency blurple lamps, or just that blurple is no good? Is the advancement of cob usage due to it's superior photosynthetic absorption, or just that they are 10 times easier to mount and wire in a high wattage package?

Click to expand...

It'll most likely grow a plant. Same as any other cheap Chinese light. There are lots of pictures of people using cheap blurple panels on other forums, they just got shunned here.

Rahz said:

What is the right spectrum and who said anything about lumens? If there's some truth to a balanced full spectrum light source being better than red/blue it's going to come in the form of empirical data, not opinions. It's clear that blurple hasn't captured the market but I'm questioning why that is rather than assuming cobs are better because they're popular at the moment. Total cob efficiency depends on the emission of blue light. This is apparent when we start seeing the notable drop in efficiency at 2700K so it's not clear that red shifted blue light is more efficient than producing it through the band gap.

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There is no 'right' spectrum, different balances produce slightly different photomorphogenic response. Right now those responses are still getting worked out by hobbyists and botanists alike.

The reason monochrome LED's are falling out of favor is due to the fact that plants absorb more than just red and blue photons and have other pigments that absorb light. Green wavelengths being of critical importance among other. This line of thinking led to the 'sevendy-eleven color band' led panel fad. The culmination of this line of thinking would be the heliospectra lamp that allows you to individually adjust the spectrum balance. Even then, you still end up with a 'white' light once you add so many groups of colors together

This is where the practicality of the cobs take over. They produce a white light just like the helio spectra but without the steep price or convoluted setup.

My thoughts on the matter. I missed out on the blurple phase of the LED market so I haven't experimented with them. I think Greengenes707 would be the one to direct more questions toward. He's worked directly with a few manufactures in the past IIRC.