Need Lighting Help

[remy]

Hi All,
A customer called me with a few questions. One I could not answer because it dealt with lights. I have a greenhouse window I start seeds and I don't try to grow tomatoes inside over the winter so I don't do lighting. He is growing plants inside over the winter.
He wanted to know what really are the best lights to use. He has some kind of florescent lights and was wondering about LED lights. He said some local guy he talked to said a certain power florescent mimicked real light even though it was not the strongest. He is not sure what to believe or buy.
So I told him I would ask here for him.
Thanks,
Remy

[greentiger87]

Imho, LED lights are still not ready for primetime where the average hobby grower is concerned.

The best deal is to use lots of T8 fluorescent tubes, and keep them as close to the plants as humanly possible. Reflective (painted flat white is better than mylar) barriers to trap the light make a significant difference. Bulbs rated as "daylight" are usually the best option, but it really doesn't matter that much. People tend to underestimate the amount of light needed for indoor growing, and how close the lights should be to the plants. He should use as many fluorescent tube fixtures as he can practically fit.

High-pressure sodium and Metal Halide lamps are the more advanced options, but they are a significant investment and commitment, and can have complications like the necessity for cooling, movement of the lights to balance the spectrum, etc. You (He) should wait to buy those when you're better informed and are sure this is going to be a long-term hobby.

[Cole_Robbie]

He is growing plants inside over the winter.

Do you mean he's trying to for the first time? I suspect that is the case.

As of right now, LEDs are a waste of money. Although they will get better someday.

Flouros will work...sorta. Maybe on a cherry tomato and maybe for someone who is not very concerned about fruit quality.

If he wants tomatoes that are worth eating, he'll want to use HPS lights. They have them as small as 50 watts. 150 watts is a popular security light size. A digital 600 or 1000 watt would be top of the line, but they require a massive cooling effort. And the worst part is that you tend to spend more in electricity than you make in tomatoes.

I have seen the big lights used before in commercial operations, but it was as a supplement to the sun shining into the greenhouse. They would only run the lights in the early morning and late evening. And that place was doing plant research, not selling tomatoes. I don't think it's possible to grow tomatoes profitably under artificial lights, or else we'd see people doing it.

Your customer will end up the happiest if you convince him to stick to green leafy plants and seedlings for his indoor growing. They are ten times easier.

[Hotwired]

If price is no object, then LED Growlights are a great solution with wavelengths really tailored toward the plant's requirements (PAR). I like Fluorescent bulbs, since they are a low-cost solution that work quite nice. I'm a retired optical engineer, and did substantial evaluation of commercial growlights. I can tell you that most are a big waste of money.

I use a 6500K tube (daylight) along with a 2300k tube (warm white), and I find they have the most bang for the buck. The 6500K spectral curve is suited nicely for starting plants inside http://imageshack.us/a/img560/3693/daylightcflcurve.jpg , though they fall off in the Red wavelength band needed for flowering. If you add a 2300K warm white bulb http://imageshack.us/a/img543/3018/w...tecflcurve.jpg which really helps for flowering. I start my plants inside for planting out, and most of the photosynthesis needed for foliage, stem, and root development takes place in the blue http://imageshack.us/a/img40/5696/5000kcfl.jpg .

I should warn you that when I said LED's are better, I'm speaking of high-end LED lights with a multitude of wavelength LEDs. I ran a spectrographic curve on a "UFO" light and found that the bands were extremely narrow http://img835.imageshack.us/img835/858/ufo2s.jpg . when I built my greenhouse, I invested in four 500W metal halide growlights http://imageshack.us/a/img651/5156/60070124.jpg . They were blinding, but my January electric bill was $900, and when I finally ran a spectrograph, was I kicking myself big-time. You'd think that being an optical engineer, I'd have checked it out first - but nope - tomato fever kicked in.

I'm in the process of finishing the preparation of a PDF on my study. I was fortunate to have access to most of the commercial grow lights, as well as a sophisticated spectrophotometer. I was surprised at the results. I'll post a link as soon as it is finished.

Edit: HPS and Metal Halide are powerful, but not in the bandwidth that counts. http://imageshack.us/a/img109/2284/compare5.jpg

[Doug9345]

I know a guy on the internet that is experimenting with LEDs for his peppers and really likes them. I've been helping him with the electronics that go with it.

In my opinion even if LEDs are a little better, they are so much more expensive that you might as well buy more fluorescents and have brighter light. I suspect much of the gain with LEDs is the fact that it's easier to aim the light at the plants than it is with a fluorescent.

I've used miscellaneous fluorescents and CFLs. I like CFLs. You can buy them for a couple of bucks at Walmart. I also like the aluminum reflectors you can buy to screw them into. Ones for a brooder are much better built than ones for a utility light.

Here is what I'm using to revive a two year old petunia that refuse to die plus a hundred plus little seedlings that are growing in the pot from when it when to seed.

[Cole_Robbie]

I've seen the "ufo" lights. What a joke. With the emergence of LED technology, there have also emerged a lot of sleazy companies who simply lie about their product. Often they lie to the store employee, who doesn't know any better and then repeats what they are told to the customer.

I would be curious what the spectro-gizmo would read when hooked up to an LED television used as a grow light. The spectrum could be easily manipulated. And then you could also watch TV on your grow light.

HPS and Metal Halide are powerful, but not in the bandwidth that counts.

I'm not in any position to argue with you, but if that is true, then why have they been so popular for so long? Are you comparing them to technology that doesn't exist yet, or is prohibitively expensive?

[Hotwired]

The idea that you need "huge" amounts of light is seriously overrated. When you put 500watts on a plant with HPS, you are actually hitting the plant with the equivalent of 60 watts for most of the par wavelengths. Here's the spectral curves http://imageshack.us/a/img109/2284/compare5.jpg . I was totally shocked when I ran the curve - Not at all what I'd expected. I'll try to get my PDf on commercial grow lights ready over the next week. It's a real eye opener.

As for the LED TV, I had to think about that one a bit. LED TV's have three different colors, Red, Green, & Blue, and they're in very narrow wavelengths. What you are seeing is the combination of these wavelengths in varying intensities, so it appears to be the full spectrum. It's your mind that translates this into oranges, yellows, etc. Plants see these lights as three separate colors in vary narrow bandwidths.

[greentiger87]

Originally Posted by Cole_Robbie

[I]
Your customer will end up the happiest if you convince him to stick to green leafy plants and seedlings for his indoor growing. They are ten times easier.

Totally agreed. It can be done though, Raybo is proof of that. Is it worth it?

http://www.tomatoville.com/showthrea...t=20459&page=9

[Cole_Robbie]

The idea that you need "huge" amounts of light is seriously overrated.

I see your point, but is there an alternative? LEDs could be it, but it's not cost-effective...yet.

Another question I'd have - is there more to it than just spectrum? Despite appearing to be so wasteful on a spectrum curve, does a high-power light have more of a penetrating capacity? If the light can carry farther past its initial contact with the plant canopy, that would be a benefit unrelated to spectral curve.

But then again maybe having multiple point sources like a typical LED negates some of that penetrating benefit as compared to having one big light.

[remy]

Thank you everyone so far! You have been very helpful.
Remy

[gixxerific]

I use flourescent. I have a mix of T12 - T5. Going for a big T5 this Christmas. I would definately look for T5 they use less power and have great lighting.

The leds are cool but they are super expensive for what you get. And what your friend is doing is no that.

This is my mess a few weeks ago.

[Rgold1963]

Not to disagree with anyone but I have grown tens of thousands of plants over the last 30 years with just about every type of "grow light" that has been made. I have grown plants to complete maturity both with and without natural light in either commercial greenhouses or smaller enclosed growing areas. I have experimented using different lights on their own as well as combining different types of light together and for tomatoes, I have found that metal halide is by far the best when used with no other light source at all and also found that plants in the greenhouse did perform better when they were under the metal halides as opposed to the HPS during the darkest parts of the year in the PNW. When I first started using artificial light for growing, there were not as many options out there as there are today and there were also not MH and HPS bulbs specifically made for growing plants like there are now.
The cost of electricity has risen 700% since I started my business back in 1989 and has made it unfeasible to produce tomatoes through the Winter any longer here so I changed my growing season several years ago. This year, I am working on getting my plants into production 4-6 weeks earlier through the use of MH light and a small "grow room" that is much less expensive to operate than a full sized greenhouse. I won't know if it's profitable until later in the year but I will post the results once I find out.
Upon researching the newer technology in HID as well as LED and florescent lighting, I opted to go with 1000W MH as the most economical and most proven technology to date. I did help setup a growing chamber test earlier this year using an LED and one of the new high output CFL type lights and was very impressed with both of them however, the cost/output ratio is still not quite there yet with both of these. I will say that the plants under both of those lights came into production much earlier than the same seedlings did that I planted out into my greenhouse under natural light. The fruit quality was equal in brix and shelf life but due to the size of the growing chambers, the plants were removed long before my greenhouse was finished for the year so overall yield was not able to be compared.
While I have not used a spectrophotometer, I can see a large difference in the wavelength output of the different types of MH bulbs on the market today and need to do some real works testing of these different bulbs to see if it's all marketing hype or they really do put out the light the manufacturers claim. As of today, the MH bulb that seems best suited for plant growth is the EyeHortilux Blue lamp. While ridiculously overpriced, the spectrograph from the manufacturer appears to show it has the most usable(highest PAR) light of any lamp out there. There is another manufacturer about to release a similar spectrum bulb at a much more affordable price but there is no set release date at this point. I am currently using two different bulbs from that manufacturer in my current setup. They are quite different in color temperature and it should be interesting to see how the plants react to that as things move along.
I will post more information as my experiment progresses.

Ron

[Cole_Robbie]

That's interesting. It seems to be the opposite of what manufacturers say. But there is no arguing with your own experience.

That hortilux bulb is the "red" metal halide, right? They also have a "blue" HPS. They're trying to deliver the best of each kind with both products.

I have read that halide bulbs degrade much more rapidly than HPS bulbs. I have also read that they can explode if they get too hot and send 1000 degree glass everywhere:

http://www.usa.lighting.philips.com/...oads/mh007.pdf

WARNING:The arc-tube of metal halide lamps are designed to operate under high pressure and at temperatures up to 1000º C and can unexpectedly rupture due to internal or external factors such as a ballast failure or misapplication. If the arc-tube ruptures for any reason, the outer bulb may break and pieces of extremely hot glass might be discharged into the surrounding environment. If such a rupture were to happen,THERE IS A RISK OF PERSONAL INJURY, PROPERTY DAMAGE, BURNS AND FIRE.

I would think explosions would happen from improper cooling, like using an air-cooled hood and either not using a blower or having it fail. HPS lights can blow up, too, but it tends to be the internal glass that ruptures, and there is much less risk of fire, because it doesn't drop molten hot glass everywhere.

[Rgold1963]

This is the EyeHort bulb: http://www.eyehortilux.com/products/Metal-Halide#blue
If the spectrograph they show there is true, it is the best bulb for all stages of plant growth with tomatoes and probably most other things. They also make a dual arc tube that is part HPS and part MH which I have not tried.
As far as the bulbs breaking, I have literally installed thousands of MH and HPS bulbs in greenhouses without ever having a single one break. I have heard of it happening and it usually involved someone striking the bulb. That is why they say that you must use in an enclosed reflector as the glass cover of the reflector not only protects the bulb but keeps hot glass from falling onto anything.
As far as my experience vs what the manufacturers say, I have had plenty of reps tour my greenhouses and show me their little charts on how much better their lighting is but not one of them could take me to an actual facility where any sort of testing was being done. It was all simply on paper. I showed them plants that were under both types of lights(in the greenhouse) and even though the plants under the MH were healthier and loaded with more fruit, they still wanted to believe that their little charts were right because they were written by scientists and after all, I was just a farmer. I have always been the type to want to actually see proof rather than have it told to me by a salesperson.
Again, it comes down to real world situations rather than laboratory testing if you are going to survive in this industry. If I had a dollar for every time someone has come into my greenhouse and told me they were going to make me rich with their new product, I would no longer be farming!

Ron

[Hotwired]

I looked at the advertised spectrum of the Blue Halide. It is really superior to other Metal Halides, but it still is not a good match for PAR http://img163.imageshack.us/img163/4773/bluehalide.jpg . I still stand by my statement that high end LED lights are superior to Halides or HPS. Sodium is terrible in the blue wavelengths. The best Bang for the Buck are CFL's or fluorescent tubes with a combination of Daylight 5600k and Warm White(2400k).

Of course if you have a row of 1000 watt Blue Halides then they're going to be superior to fluorescent bulbs because of the density of light per square meter. A jet goes faster than a motor scooter, but the capital cost per mph and energy cost make the jet not nearly as practical to the average person.