Light supplement for seedlings

[naoki]

It sounds like quite a challenge to satisfy the orchids with various light requirements (especially those high light plants)! I grow mostly low light plants under LED, so you may need quite a different approach.

My grow tent is 120cm W x 60cm D x 150cm H. I have a thermostat and the exhaust fan kicks in at 86F. But once the exhaust kicks in the RH drops (60-80%) to the ambient (20-30%) quickly. A humidifier controlled by a humidistat kicks in, but it can't catch up with the exhaust. This problem occurs only in the summer (I'm in Alaska). I minimize the problem by switching the day and night phase.

So you might want to be careful with heat management since if you have to run exhaust most of the time, there isn't an advantage of the enclosure.

One thing I have thought is to use water-cooling for the LED. So if you need pretty strong light inside of the enclosure (and if you can do a bit of DIY), this might be a way. I'm still digging around with this option, but it doesn't seem to be cheap.

The difference between the flood light and PAR is the LED technology. I don't completely understand, but the flood light uses chip-on-board (COB)/multi-chip style emitter. COB is a newer (and supposedly more efficient) generation in general. Some people says that these cheap ebay COB LEDs aren't the real COB. After putting together the DIY cheap COB in the thread, I got a "real" COB (Cree CXA3070). They don't look similar, indeed.

BTW, with the flood light I put the link, I was talking about the white LED, not the RGB type (which isn't efficient).

[Yéri]

Did you notice any difference yourself after buying the 'real' COB?

As for the relative humidity, I might not have the same issues, as the enclosure would be slightly open in order to have the greenhouse air transit through it. The RH for intake would be around 70% already, so the drop wouldn't be that dramatic. I was thinking of adding my Superfog installation and have it go off regularly in order to keep everything more or less stable.

This is why I originally purchased the enclosure. Seedlings are more fragile to changes in their conditions, which is why I wanted to give them a small space where the differences would be minimal.

Looking at the wattage and dimensions (10cm high) of those you linked on eBay, I doubt I would be able to have them far enough off my plants for it to cover the whole area. I'd probably go for 2-3 10W ones, but that would have just as much energy consumption as a regular T8...

All I really need is strong light supplement (I mentioned I was getting daylight, but going through 2 layers of polycarbonate reduces its efficiency/intensity, especially when the roof layer of the bigger greenhouse is not clear), so after all this search, settling for a growlight T8 kind of thing doesn't sound too bad...

It's a terrible ending to my journey in this thread, but I feel like throwing in the towel on this one. I though there might be (as many of us I assume) some kind of fantastic LED orchid grow light, but it seems like we're not quite there yet

[Discus]

These look quite interesting : LED Vivarium-Grow Lamp $24.00 Lighting First Rays

Several years ago, I bought an inordinately expensive dimmable Osram LED GU10 "halogen" replacement. It died recently, after nowhere near its claimed life.

[Yéri]

Well that's one of the types of lighting I've been looking at as well.

Unfortunately I'm not located in the US, so shipping might cost me quite a bit! (42,15$ to be precise if I were to buy 2 of them)
I've ended up many times on Ray's website when looking for LEDs for growing orchids. Problem is I'm not certain what vendors we have in Europe/UK I could fully trust to have decent grow lamps.

eBay has tons of them, but as naoki pointed out, there can be a lot of 'fakes'.

I'll keep looking!

[OCRC_Dir_China]

Ok I think I can help with this; if you are looking for energy efficiency you must first know your true power source value, 100v, 120, 130, 210, ect….. you could have 125v or 127v measure it then look at the wattage of the light and due the calculation then you will know its true power consumption.

What you are talking about, we call them growth racks; and we use just standard 2 bulb 40 watt florescent light fixtures, on timers we do have light switches so we can control what bulbs we want on or off. If you go to Social Groups and then to Flasking ect……… I posted some pictures of our growth room and the growth racks you can see. If you are going to play with growth racks you should get some kind of light meter to check light levels.

[naoki]

Yeri, I hope that I didn't discourage/confuse you by bringing in more choice/info.

Some of your species may be happier with higher than 70%RH, but most should be ok with that RH, right?

With regard to heat, my experience is that all florescent lights (T8 and T5HO) are more problematic than LED. This is the reason that I started to explore LEDs. You could disassemble the florescent fixture, and bring the ballast outside of the enclosure.

Also, even though energy consumption may be same, light output would be different. Whatever you use it, I'm guessing that you'll need quite a bit of wattage to satisfy Dimorphorchis lowii (depending on how much natural light you are getting in).

Can't you replace the relevant sides of polycarbonate panels with more translucent materials? Or if you want additional artificial light, you can replace the top panel with glass, and put whatever light on top of it.

I have one of Ray's (the one Discus suggested), and it seems to be good if the space is tight. The height is about 1.5", and it has very wide, and even light spread.

In Europe, I hear good thing about this unit: Led growlight, 65 watt
It is pretty low watt, but it uses high quality components, with high efficiency as a goal. I calculated the cost of DIY'ing this panel, and it wasn't worth doing DIY.

I personally don't know if the ebay COB should be called "fake" COB or not. I haven't put the CXA3070 together (waiting for the driver). But the difference would be efficiency. Well it's 5 times more expensive ($8 vs $40 for '100W' class emitters), so I'm expecting the difference in efficiency. I'll post the "rough" measurement, once I get it going.

Director, this kind of meter is an easy way to measure approx. energy consumption. Even with T5HO/T8 florescent light, actual energy consumption is different from the rate of the bulbs.

[Yéri]

It's not discouraging as such, it's just frustrating sometimes

I just thought I'd get the enclosure and take care of a bit of extra lighting at low energy consumption and voila!
Seems like there's more to it than that, much more!

Anyway, that LED growth sounds the bomb, but it's way above my budget...

We've been talking about so many types of lighting...what about PL-lights? I found a shop in Brussels that sells some bulbs that look all right! They mention it has very low heat consumption (5-10cm off the plants)

FLUO COMPACT 55W SUPERPLANT CROISSA - Culture Indoor Bruxelles

Just don't know if they have 60cm ones. It would be easy to install as well.

All I can think of looking at, is a LED lamp that fits into a 2G11 base...but I suppose there's a lot I haven't thought of!

[naoki]

Originally Posted by Yéri

We've been talking about so many types of lighting...what about PL-lights? I found a shop in Brussels that sells some bulbs that look all right! They mention it has very low heat consumption (5-10cm off the plants)

FLUO COMPACT 55W SUPERPLANT CROISSA - Culture Indoor Bruxelles

Just don't know if they have 60cm ones. It would be easy to install as well.

All I can think of looking at, is a LED lamp that fits into a 2G11 base...but I suppose there's a lot I haven't thought of!

I used to use this type of light for planted aquarium before T5HO, but I don't know much about them. Mine was as hot as normal T8/T5HO. I think the efficiency was slightly lower than T8/T5HO, but I may be wrong. Karma, who has cool blog and set-up in Sweden, uses PL florescent light. You might want to check her page.