Now that my greenhouse is overflowing (standing room only) with paphs, I am planning on building an artificial light room in my basement. The room will be 12 x 14. I would appreciate any information from other members about the HID wattage they use (I am considering 6 x 400watt units) and the distance between the plants and the lights that they would recommend. I have gotten conflicting information form various hydroponic stores about the area that one 400 watt light with illuminate sufficiently for growing paphs- suggestions? TIA

This may not be aplicable to your situation, but I'm using a 430 watt SonAgra bulb in the one HPS fixture that I have. It is suplemented with indirect light from NE and NW windows. The room is 9 x 10. It sounds like 6 units would be overkill unless you're growing tomatoes or Vandas. I have some Phals and Paphs that are four feet away from directly under the light and they have been growing fine. Seedlings are on the floor, at least 7 feet below the light.

I would suggest that you contact an orchid grower that sells lights, at least to get their recommendations. Here's two:

Jerry Fischer, Orchids, Ltd. http://www.orchidweb.com/

Hadley Cash, Marriot Orchids http://www.marriottorchids.com/

My indoor grow space is about 8 x 6 and I'm using a 430W HPS with a SonAgro bulb on a light mover and the light is about 2-3' above the plants depending on the height of the plants. No natural light but my plants grow and bloom beautifully. For your space, I would think a 1000w should do, less if you have it on a light mover. A light mover makes a big difference! Hope this helps!

Thanks for the replies. A major paph grower indicated to me previously that a 400 watt HID bulb would illuminate a 4' x 6' area at a high of 4' above the plants. Other sources have said that for paphs the ideal area for a 400 watt bulb would be 40" x 40".

I think using a 1000 watt bulb on a light mover has possibilities, but I would be concerned that the plants parallel to the track and at the outer ends would suffer from 'shadowing'.

Further comments appreciated :D

How about using a rotating light mover instead of one on a single straight track? That should help.

My main concern with light tracts, whether straight or rotating, is that for a certain period of time some of the plants will not be properly illuminated (i.e. 1/2 the time).

I am considering two straight tracts spaced 4 feet apart, each with a 400 watt fixture, and lining the walls with mylar to minimize shadowing.

Would it be preferable to use two 600 wat fixtures to overcome the fact that the lights are moving?

I have also lined the walls with mylar and mirrors to reflect the light back on to the plants and that also help a lot.

Thanks for your help Peter. I believe that mylar is actually more reflective than a mirror - go figure!

Thanks for your help Peter. I believe that mylar is actually more reflective than a mirror - go figure!

I don't know but mirrors are also heavier and I worry they would come crashing down on the plants, so I only have mirrors on one side and the rest is all mylar.

I have experience in this exact area. I grow using 400w MH lights and sunlight.

Their spacing should be 6-8' from each other, if you have them suspended about 8 feet from the light source to the top of the plants. This will give you about 1100+- lumens per sq/ft, assuming your light source produces about 28-31k lumens.

ST

Hi Steve, by my calculations 1100 lumens is about 102 foot candles.

24" below a 400 watt bulb gives 1500FC, so I think 4 feet above the foliage would be better for paphs.

am I miscalculating?

You'll have to calculate it by the spread of the ballast reflector.

If you have a 30000 lumen source, and it is concentrated to one square foot, that would be 30000 lumens/sq ft. If your ballast reflector is shaped in such a way that at X ft from the source, you have a total coverage area of 30sqft, you have 1000 lumens/sq ft., regardless of the distance it is from the plants. You want to have about 30 sq ft of coverage, so a diameter between 5-6' of light is created, at the point where the light is at the leaves. It depends on the shape of your ballast reflector. with only 4' from the plants, with a normal semi-sphere deflector you will probably burn your plants in only a few minutes.

Just calculate power of your known source, and divide it by the area covered, and vary the distance to make sure you are about 800-1000lumens ft OR LESS, as need. Remember, light is like fertilizer, it is always better to have too little than too much.

I must be missing something in my light intensity calculations. A 400 watt HID bulb emits approximately 40,000 lumens of light measured 1 foot from the bulbs.

Light Intensity = Initial lumens/ distance squared

So 4 feet below a 400 watt bulb there would be a light intensity of
40,000/9 ( 1 foot at initial reading + 3 feet additional ) = 4444 lumens

4444lumens = 412 foot candles

Three feet below a 400 watt bulb the light intensity would = 929 foot candles

Interesting discussion.... What is a light mover? I'm assuming it is a track that runs across the ceiling where a motorized light fixture slowly moves back and forth??? I haven't heard of such a contraption before.

You are correct Slipperhead. I think the main advantage is that the track movement is cheaper than purchasing enough lights to get full coverage of a growing space.

I suspect it also reduces the risk of cooking ( it seems like they move at an inch or so per second), and probably keeps plants from growing in one direction.

Yes, they reduce those hot spots and plants grow more evenly and straight up instead of leaning towards one direction.

I must be missing something in my light intensity calculations. A 400 watt HID bulb emits approximately 40,000 lumens of light measured 1 foot from the bulbs.

Light Intensity = Initial lumens/ distance squared

So 4 feet below a 400 watt bulb there would be a light intensity of
40,000/9 ( 1 foot at initial reading + 3 feet additional ) = 4444 lumens

4444lumens = 412 foot candles

Three feet below a 400 watt bulb the light intensity would = 929 foot candles

That is a calculation which does not take into account the reflector. Consider if I created a reflector that let out a single point of light just a single centimeter. At 4 feet away, the sliver of light would still be nearly 20000 lumens because of its tight beam. The fact that there is a reflector on it removes the light intensity judged by distance as a constant. So what you must calculate, then, is no longer the theoretical light due to expected distance of the source, but total light area covered. If you have a reflector behind the bulb, you're also getting nearly twice the light intensity as you would have been without one, but my calculation will take this into affect. For this we would assume no loss of intensity, but depending on your relfector, it could be as little as 10% loss - 50% loss (by absorption.)

So we're calculating what area the light actually covers, which gives us much more accuracy. What you weren't taking into account was the reflected light. Else you would definitely fry your plants with double the intensity you meant to give them.

To get even more accurate, i'll assume that 60% of the light is already going the direction you want it to. So 40% of it isn't, and will have to bounce off the reflector. If you have a medium luster aluminum reflector, you are probably getting 75% of the light reflected. Let us also assume that after hanging my lights, it produces a spotlight of about 6' diameter. So:
D= 2r
Area = 3.14 * r^2

[(Light coming direct) + (light reflected back)] / (Area the light is covering) = Lumens / ft^2
[(30k * 60% * 100%) + (30k * 40% * 75%)] / (3.14 * 3^2) = 27000/28.26 = 955 Lumens / sq ft



So if each of my lights creates about a 6' spot of light

And the problem with light movers: The burn you're talking about isn't because of heat, but because of light intensity, which probably won't be reduced much if the lamps stay on the plants for any amount of time. It is just like giving full frequent bursts of sunlight to an orchid. Short periods of over-intense light is not the same as even periods of durable intensity lighting. Not to mention, it stresses the plants, which means less growth, and can still kill the chlorophylls.

A light mover has two advantages. It enlarges the area that one light can cover and it reduces shadowing. Shadowing occurs when a single fixed light source is used - i.e. the top of the plants get proper illumination but the 'sides' don't - so new starts (growths) are poorly illuminated. With multiple lights there is enough overlap of light to make this less of a problem. A light mover also insures that the plants at the end of the growing area get the same amount of light as those in the centre.

Is the "light-mover" quiet?

I don't know what the length of the track would be but I can understand how you might not get enough light per day per plant. Perhaps you would just let it run longer?

How long can the track be?

Interesting concept!

Light movers come in 4' and 6' tracks. For me, light movers are a must, no disadvantages whatsoever! In fact, I highly recommend light movers especially those who grow indoors with HID systems with no natural light. My plants have been growing happily straight up ever since I installed one, no more leaning to one direction. :lol:

Here is a link to the homepage of one of the more popular light mover manufactures. It is also the cheapest source I have seen for them.

http://lightrail3.com/

Hope it helps!

Kyle

It would be cheaper just to buy another light.

Another light may be more economical initially, but two lights would cost more to run and you would have the additional concern of twice the heat output

Another light may be more economical initially, but two lights would cost more to run and you would have the additional concern of twice the heat output

EXACTLY! My grow space was a little larger originally with 2 HPS systems before I got the light mover. The light mover helped tremendously cutting down costs and my plants are all happy at the same time! I can never do without my light mover.

I agree with Steve that the initial cost of buying a light mover is high, but when the cost of electricity is factored in, the light mover is an obviuos choice. Sometimes we have to look at the big picture.

Does anyone know anything about those 'new' T5 flourescent lights? They are supposed to be very bright (way more then T8s or 12s) and have a more dependable quality of light.

Kyle

On my buddies set ups I can't hear any noise from the light movers over the fans, but in one case his bedroom is over the garage where his lights are set up, and he hears the "vibratrion" of the motors resonating through the floor joists.

He just needs to pad the track mounts to quiet this.

You may be saving money, but the money you are saving is directly proportional to the energy you are keeping the plant from producing greater growth. You spent so much money on the plants, I would think that an incidental such as ample intensity would already be an assumed cost of owning the collection.

If we are to assume that you are running a light mover, the plants are probably only getting about 40-50% of the energy (10 ft. span) the would have been getting during that time, which means a direct decrease in energy and thus growth. Obviously nobody cares about the implications, because it looks good and solves a concrete problem, while creating an intangible problem. But you can have your cake and eat it too... but it will still cost more money:

If you have to decrease your light intensity, you can make up for it by increasing your daylight hours. Which means more electricity consumption.

The bottom line is, you're trading off plant growth for money savings.
I run two 400w MH lights for 12 hours a day, and in addition running an apartment. My monthly electric bill is about $200. This extra $70 a month is part of my costs for plant upkeep. Just cost of the hobby/business.

My plants are all growing and blooming fine and beautifully for years with my current setup with the light mover, so no need to mess with anything. My personal experience tells me that this setup is perfect for me and my plants. :D :-dance:

I still like light movers.

If you ever read any of those light forums on marijana grow sites (if you seriously research HID lights your bound to end up there..) those guys have done lots of research on light movers and growth rates and flowering. Of course nothing scientific, but some of those guys do run pretty good experiments. They conclude that a properly adjusted light mover will result in a insignificant decrease in growth and flowering.

Kyle

I still like the sun.

I still like the sun.

I do too, although it would be a lot easier to use if we would see it during the winter around here...

Thanks for all the responses. Now a new question Does anyone have a problem dealing with the heat generated by the HID lights?

The grow room I am building will be off the garage and underground with a heated sunroom above. The grow room will be 13' x 14 ' x 9' high. If I use 6 x 400 watt lights am I going to have a big heat problem. I live in the U.K. and in the winter occasionally get snow that doesn't last.

If you have to decrease your light intensity, you can make up for it by increasing your daylight hours. Which means more electricity consumption.

The bottom line is, you're trading off plant growth for money savings.
I run two 400w MH lights for 12 hours a day, and in addition running an apartment. My monthly electric bill is about $200. This extra $70 a month is part of my costs for plant upkeep. Just cost of the hobby/business.

I mostly agree with this, although there are some hidden advantages to light movers. 1) Less heat - two lights are hotter than one, even if you run the single one longer. 2) We are usually wasting light intensity, there is a limit to how much a plant can absorb. 3) Less initial capital expense. 4) You don't need to run one lamp twice as long to get the effect of two lamps...

The real way to determine which setup is going to work is observation. Lightmovers seem to work pretty well for a lot of people. I preferred the 'non-mover' approach for my own growing room. But every situation is different. The plants will tell us when they aren't getting enough light, if we watch them closely.

You need to invest in some energy efficiency if you are spending that much on electricity. My whole house, when I was running well over 1200W worth of HID lights, only cost me ~$120 a month. And I have old power sucking appliances. Perhaps you need that much electricity for utilities (heat, hot water, etc). But consider using compact fluorescents wherever you can, at least. They are cheap. I've replaced almost every lightbulb I can with these, and it really helps. A little investment in energy efficiency can really pay off in reduced electric bills. There are a bunch of other cheap ways to save on electricity too.

Thanks for all the responses. Now a new question Does anyone have a problem dealing with the heat generated by the HID lights?

The grow room I am building will be off the garage and underground with a heated sunroom above. The grow room will be 13' x 14 ' x 9' high. If I use 6 x 400 watt lights am I going to have a big heat problem. I live in the U.K. and in the winter occasionally get snow that doesn't last.

This is a good case of where a light mover might be a good investment. Fewer lights = less heat. Even if you have to run them a little longer.

Look around at the local hydroponics stores, they are the ones who know how to use these things. But I would recommend a powered ventilation system. There is one for the Hydrofarm lights, it is a little fan and duct system that hooks right up to the light assembly. Vent the air outside the growing room. If you can get remote ballasts with long cords, do that. Keep the ballasts outside the plant room if possible (they kick out most of the heat).

I rigged up a system at a friends house where we put in a vent to the outside. Hook the vent up to a powered fan, and put the fan on a thermostat. Make sure there is a vent for intake and exhaust... If nothing else, you could vent to the rest of the basement. Best if you can vent to the outside, otherwise the humidity really gets out of control in the basement.

Rob

I have been searching out the type of reflectors available for HID lights. What type are you using and are you pleased. I notice that some have enclosed ends and others have open ends (which I would think would allow light to escape and not be focused down onto the plants).

Does anyone have pictures of their set up?

I mostly agree with this, although there are some hidden advantages to light movers. 1) Less heat - two lights are hotter than one, even if you run the single one longer.

I've never had a heat problem. ? But I also relocate the ballasts from the sockets for convenience.


2) We are usually wasting light intensity, there is a limit to how much a plant can absorb.

I don't know about you, but I'm not wasting any intensity. All you have to do is gauge the leaf color of the plant. Dark green, too little light; Chlorosis, too much. Hawaii green = excellent. If you're wasting intensity, you should move your light up higher to create a bigger spread to reach correct intensity.


3) Less initial capital expense.


Okay.


4) You don't need to run one lamp twice as long to get the effect of two lamps...

You're right, you actually need longer than twice as long. This is the daylight hours principle of horticulture. You've just made your light your bottleneck for growth.

Intensity x hours = X lumen hours
ME: 1000 lumens x 12 h = 12000 lumen hours
YOU: 400 lumens x 12 h = 4800 lumen hours

If your giving them an average of 400 lumens instead of the 1000, that is only about 40% of what they were using before.

So to get back to the same amount of energy you give the plants, 12000 lumen hours, you would need 30 hour daylength periods. Since you probably won't go over 20 hours of light, you have a deadweight loss of 10 x 400 = 4000 lumen hours.

So, you can either run two lights for only 12 hours a day, or try to give the same amount of light from one light running 30 hours a day.

It's true that plants will acclimate to the amount of light you give them, but that says nothing for their growth. But by limiting the light, the source of plant energy, you have made that crippling effect the glass ceiling of your growth, even with the law of diminishing returns. Of course, if you can't recognize the difference, then just use one light and spread it around.

Steve - In your example of going from an initial light intensity of 1000 to 400 lumens, are you not assuming a light tract that is at least doubling the growing area using the one light? The light tracts available in the U.K. , where I live are 1.5 meters long (just under 5'). From my reading standard light tracts increase the growing area by about 30%.

SteveT wrote:

I don't know about you, but I'm not wasting any intensity. All you have to do is gauge the leaf color of the plant. Dark green, too little light; Chlorosis, too much. Hawaii green = excellent. If you're wasting intensity, you should move your light up higher to create a bigger spread to reach correct intensity.


Eureka... I think I may have just found the disconnect. Unfortunately, not all of us can raise the light to the right level. For example, in my old grow room, my ceiling height was 7.5 feet. This happened to work for me, with the lights I had.

I've seen 250W, 400W, a few 800W (very expensive) and 1000W lights. But nothing in between, and you can't run a dimmer. So if I really need 300W to illuminate my plants, and I can't lift the 400W bulb up higher... Far better to make a longer growing area than to put up some sort of shading material. Similarly, if I needed 800W, it is probably cheaper and easier to run a 1000W fixture over a slightly larger area.
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Steve - In your example of going from an initial light intensity of 1000 to 400 lumens, are you not assuming a light tract that is at least doubling the growing area using the one light? The light tracts available in the U.K. , where I live are 1.5 meters long (just under 5'). From my reading standard light tracts increase the growing area by about 30%.

The greater you increase your area that the same amount of light falls upon, you must also equally discount your light intensity, because you have not multiplied it equally by your increased growing area.

The way to raise the lights is to remove the socket from the ballast, and wire them together as they were before, but with extension cord. This way, you get another foot of light higher, which will greatly increase the spread. Another way is to use a different reflector. They make parabolic reflectors of many different sizes, anywhere from flat to a dome to meet your light spread needs. What you might consider is making one and lining it with reflective mylar, that way you could bend it to the right shape you wanted at any height.