Lighting

It is a really tall cabinet. Where are you going to attach the light? If you are thinking of attaching it on the top, it is difficult to get an even coverage. As you double the distance from the light source, the intensity of light decreases by 1/4. So, a tall cabinet is somewhat tough to use. One way to get around this problem is to use narrow beam optics (like spot light). So you can have two kinds of light. Some light fixtures with relatively wide-beam angle for the top part of the enclosure, and multiple narrow beam fixtures (basically spot light) to provide light for the bottom part of the enclosure.

Both of the fixtures you linked are high quality (even though they are over-priced). The first one uses Luminous and the second one uses Citizen. Both of these can achieve high efficiency. The first one could work well, but you might have difficulty getting even light coverage to grow orchids. It is a bit over-powered for your space, so you probably need to dim down (if you want to grow them along the wall). For the second one, the two LED modules are close to each other, so it acts like a point source. So it is even harder to get even coverage. Since one of the second one is similar to 1/2 of the first one in terms of total output, you could achieve similar effects by using 2 of the second ones.

Are you in UK? I'm not sure if they ship this internationally, but this is probably much better deal: 200 Watt Citizen CLU048 (4) COB Grow Light Kit
Then I would put narrow beam optics to two of these, and the others are for the top part of the enclosure. This is pre assembled, so all you have to do is to attach the light. You still probably need to dim a little bit (depending on what species you are growing). With 200W of high quality COB, I can easily cover 4'x4'x4' enclosure. In your case, around 150W is probably a good start (for low to moderate light orchids).

If you are handy, you can easily make something similar (you'll save $100 or so over Timber kit, about $200).

With plants, Lumen isn't too relevant. Human eyes are sensitive green, so we feel a little bit of green light is brighter than lots of red or blue light. But plants have different sensitivity. You can think all photons in the visible range are useful for photosynthesis. Actually this is a simplification, but PAR related measurements are basically counting the number of photon flux in the useful range (400-700nm) without considering that the green photons are good. Here is a better explanation: http://www.gpnmag.com/wp-content/uploads/16_TechnicallySpeaking_GPN0913 FINAL.pdf

High PAR photon flux per given electricity (micromol/J) is the relevant efficiency measure of grow light fixtures (instead of lumen/W). These high quality COBs have very high efficiency, and you want to target around 2.0 micro mol/J range. If a company doesn't give this kind of specification, you can assume that they are not too good. If you are comparing white LEDs vs white LEDs, then lumen/W is a good approximation (150lm/W is considered to be decent). Both fixtures you linked are around this range, so they are good.

 

Hello, I see you have been considering MIGRO LED grow lights.
I am from the company and would love if you would use our lights and show case them and post pictures online. I am happy to offer a very significant discount to you in exchange. I would help you with the setup (by the way, Naokis comments above are very well informed!).
We are based in Ireland so I can send lights over to you on sale or return so you can check them out first if you wish.
Let me know what you think.
Take care, Shane Torpey - [email protected]

 

You are correct that the single isn't enough for sure. MistKing LED doesn't give enough specs to compare, but even the double is about half of the output and probably 1/2 efficiency compared to MIGRO 200. So you'll be paying a lot more for electricity over time. Also, MistKing's LED is likely to be using very cheap COB LEDs from China (most of the decent COB LEDs have a round configuration instead of square). There is a good COB from China with square configuration, but it is unlikely that they are using this from the lumen output. They are charging for the gimmicky color control (I understand that some people like this kind of things), but it is quite a bit of rip-off in my opinion.

I'm using Mist-King mister, and it seems to be a good product (but expensive). But Gregg Zollinger has posted a much cheaper alternative in his thread. I followed his recommendation and got the pump and mist heads, but I haven't started to use it. So you might want to check his thread.

Shane, I'm not too familiar with Luminus products, but their Gen 3 seems to be very competitive. I was going with Vero 29 Gen 7 for my next fixture, but I need to make a comparison. Is your product using CXM-32 or 27 Gen 3? Is it 3500 or 3000K, 80CRI? I like the giant passive heatsink of your product.

 

Hi Naoki, My experience with the big brands, Luminus, Cree, Samsung, Bridgelux etc. is that they are much the same for build quality and reliability. The Luminus package is the most efficient at the moment in the power range we require.

The chip we use is the CXM 32 Gen 3, 3500K 80CRI. We drive them just under their rated current of 2.2Amps and they run nice and cool at only 25deg C above ambient. For horticultural applications the lower CRI specs are perfectly suitable and a little cheaper .

I agree with your comment that our lights are at the expensive end of the range. However all the components are the best quality available, have a 3 years warranty and deliver the highest efficiency around. This will mean much less power consumed but most of all much less heat, no noise, IP 67 etc.

I am happy to offer a discount code to the members on this site in exchange for some sales (obviously), but also in exchange for publishable photos of the lights in situ for ornamental grows. I can offer bespoke lenses and colours, if necessary, for the application. It would be fun to work out optimum lighting configurations for this area.

To give you a little confidence in the product I can post you one to trial if you like?

 

Thank you for the clarification, Shane. You might want to put this kind of info to your web site since it shows that your company knows what you are doing (unlike many other shady LED grow light makers)! I agree, I still go for the lower CRI in general. It used to be lower CRI had a higher efficiency in terms of PAR. I haven't done comparisons recently, but higher CRI is getting better, and I think the efficiency is getting really close (especially in terms of YPF, yield photon flux, which uses McCree curve). But if higher CRI is more expensive, it isn't worse going for yet.

I agree that DIY isn't for everyone, and your fixture is a nice package and gives the opportunity for those people to use high quality grow lights.

I think that orchid growing is a small market compared to the other markets, but if you expand your lines, smaller COBs might be more appealing to orchid growers. I use 4x CXB3590 to cover 4'x4' (120cmx120cm) area, but I still need to dim it down to about 40W each (total of 160W or so).

With your 90-degree optics, I noticed that your PAR intensity map isn't spherical, and more like square. Is it really the case, and you are doing it with glass lens (instead of silicone)? I know that some silicone optics (e.g. Khatod) can make really flat square coverage, but I didn't know (affordable) glass lens can do it. If so, it is very cool!

The photo of your driver shows 1.75A, but actually you are using 2.2A?

 

Naoki,

Not many people are interested, care or least of all understand what CRI, colour temp etc is. If they do understand they will usually decide to self build so not much point trying to appeal to them.

I love your eye for the detail, thanks for proof reading the site for me! ha ha. As i said before I would love to send you a light and give it the 'once over'. It would be nice to have your critical eye look at the product. There's no other obligation other than I would hope for your feedback. Let me know what you think.

I hear what you are saying about the PAR levels being high from the MIGRO unit. What is the desired range of PPFD for orchids?

The PAR intensity maps are a flat contour chart generated on Excel. For some reason the contours generated of the circular light pattern are 'squared' a little by the software. We could not find better alternative software so we stuck with it, despite this distortion. At least it's consistent as this distortion is applied to all of the PAR intensity maps we produce. Sorry to disappoint, not cool just a software glitch!

The 1,75A driver is an early production model. As the production heatsink performed better than expected we increased to 1.9Amp and 2.0Amp drivers on more recent releases. We are still driving 10% under the rated load at worst/best? case.

 

Thank you for the offer, Shane. But I have enough LEDs which I made for now, and I'm a bit tight in time, so I don't think I'll be a good reviewer. Also with my grow area (grow tents), I can't use yours fully because each COB is too powerful, and I don't have enough head room (so I have to dim quite a lot, maybe to 50% or so). By looking at the spec, I already know that your product is very good!

There are some (but not many) literatures about PPFD requirements for orchids. In low light orchids like Paphiopedilum, photo-saturation point was around 100 micromol/m^2/s. I don't think that it showed strong inhibition at higher level. As you probably know, the saturation point is highly influenced by the other environmental factors. But I generally target around 100 micromol/m^2/s, and around 200-300 micromol/m^2/s for the high light orchids. There are many orchids which are facultatively CAM. So it is not easy to measure photo-saturation point with infra red gas analysis (IRGA, e.g. Li-Cor LI-6400). Some people mentioned that Paphs/Phals can grow OK at much lower PPFD (like 50 micromol/m^2/s). So I would say 50-300 micromol/m^2/s is a good range for orchids (for continuous, artificial light).

Thank you for clarification about the spec! I think that with the power of your products, they will appeal to carnivorous plants people (or maybe succulent plants?) in addition to Cannabis.

 

there are plenty of options available when it comes to best indoor LED grow lights. Many web owners are providing ample of information which are enough to make your move.

 

In order to choose an appropriate led grow light you need to specify what type of orchid you are planting. I have consulted a lot of sources of information to help with this. You can refer to the article on Let's Tend The Garden. It provides quite enough information about light for orchids.