400 Watt HPS/Mh enough? (Naga Morich)

[wordwiz]

Hey also (right from google)

1 lux = 0.09290304 lumen per (square foot)

so if your reading is 30K lux its only 3000 lumens per square foot. He was correct in saying that you need 45000 lumens per sq. metre which is about 4500 lumens per square foot

Meters don't measure lumens, they measure lux. And at a distance of one foot from the light source, they are the same.

From Wiki:

The difference between the lux and the lumen is that the lux takes into account the area over which the luminous flux is spread. A flux of 1,000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1,000 lux. However, the same 1,000 lumens, spread out over ten square metres, produces a dimmer illuminance of only 100 lux.

Another way to look at it: One lumen equals one foot candle per sq. ft. One FC = ~10.764 lux. A sq. ft. is .092903 of a sq. meter. That gives you a rating of one lumen equaling 1.000007892 lux.

All this science and conversions aside, I also trust my light meter. A bulb is suppose to produce 6,900 lumens and if I hold it a foot away, that's the amount of Lux I get. If I hold it six inches away, I get about double that amount, two feet away, 1/2 it. Reading a light meter is NOT rocket science.

A 250 watt HPS light is going to output 26,000 lumens. At six inches away, the object will receive 52,000 Lux, so that anyplace on that plane that is under the light will get that much light, whether you are measuring a one square inch area or a one square meter area - it's the amount of light striking any one spot.

Not to mention a six inch gap between a 250 watt HPS will not pass the back of the hand test. That is, if you the back of your hand is six inches from the light, it will not feel hot. If I hold my hand six inches from a 150 watt HPS, it gets very warm.

Mike

 

[LGHT]

These are about right since its lumens per sq. foot. Great table

Glad you liked the info, but it was pulled directly from the maximum yield website. The entire article explains lumens, lux, how and why HID lighting is superior over other light, but does have it's problems such as heat. Not sure where the thought of putting a light closer to a plant will magically increase the lumen output, but that's not correct. In fact most bulbs loose lumen output and the bulb rating is typically "initial" output as that number does decrease quit a bit over time. That's one of the main reasons I opted to upgrade my 400 MH/HPS to a 1000 setup so I can maintain MORE than enough light for MAXIMUM growth.

Here are a few articles that I read up on before deciding what light is best for my specific environment. I suggest anyone who is unclear and how and what lights to use and when read them all. Especially if you think a $20.00 light placed closer to a plant will double the lights lumen output



Getting Started: Lighting For Indoor Crops

HID Lighting De-Mystified (a little)

The Digital Sun: Better Light for Better Results

LEDs: Lighting for Hyperspace Crops or Just Hype?

There are also several other articles I've read and documented, but I love how these are plan simple and straight to the point.

 

[LGHT]

LGHT,

IMO, your data is wacked. I have a 150 watt HPS lamp and at six inches, I'm going to get 30,000 lumens per sq. meter.
Mike

Your first statement says your getting 30,000 lumens per sq meter with a 150 watt HPS.

A 250 watt HPS light is going to output 26,000 lumens. At six inches away, the object will receive 52,000 Lux, so that anyplace on that plane that is under the light will get that much light, whether you are measuring a one square inch area or a one square meter area - it's the amount of light striking any one spot.
Mike

Then you say a 250 watt HPS light is going to output 26,000, but when you doubled your number you say Lux??? Seems like your going in circles just to be argumentative. Not sure what point your trying to prove, but you may want to pick up a book and do some reading on PAR light as that's the only thing that matters to plants anyway not lumens or lux.

Here is a link to get you started. Lumens Are For Humans

 

[hydrojunkie]

I'm not sure if its me or what but this conversation isn't making sense to me. I am getting lost when you try to convert a measurement of light to a measurement of light for a given square meter, and I am especially confused as to how one could think they are getting more light the farther away one gets (probably to do with the conversion). Not to be a jerk but could you use some of these formulas to use your measurements and work your way back from 52000 lux to 26000 lumens.

 

[LGHT]

I think I figured out the formula.

Hold hand to light if hand get hotter as it get closer = more lumens.

 

[hydrojunkie]

At this point I am just trying to let the guy prove his off sounding numbers with some formulas. I think wiki is an evil internet tool in the wrong hands.When I went through the apprenticeship I couldn't just give a number, had to prove how I got from point a to point b. However lght,I believe your formula is correct. I am no expert on the subject but I can grow some plants indorrs so I must be doing something right.

 

[LGHT]

Jokes aside and to keep the post on track for the new guys that may be a bit confused the formula to calculate LUX is

LUX = Total Lumens ÷ Area in Square Meters.

So if your room is 45 square feet or 4.180499999999999 (4.18) meters and you started off with a 150 watt bulb that put out 16,000 lumens your looking at 3,827.75 LUX not 30,000.

My Eye Hortilux 400 HPS (LU400S/HTL/EN) puts out 55,000 lumens so at 45 square feet i'm getting a lux of 13,157.89 and my 1000 watt HPS LU1000B/HTL/EN that puts out 145,000 lumens is going to give me 34,689 LUX.

The key is both the bulbs listed above are full spectrum bulbs that covers a wide range of light and more importantly provides PAR light specific to fruiting peppers.

Here is the spectrum of those bulbs.

Here is a useful guide on light formulas

Light Guide: Useful Formulas

 

[hydrojunkie]

You're doing wordwizs homework for him.

 

[wordwiz]

OK, I'll bow out and let you all to do your own thing. The hand thing is an old method that has nothing to do with lumens, lux or foot candles - sorry that escaped you. It has to do with the heat and how a plant can handle it. Don't trust me, Google it.

I really don't care if you like/dislike, agree/disagree with the info or not. It was presented freely and thus is worth nothing. Stick your seedlings six inches under a 250 watt HPS light. It won't make a difference to me - I'm not going to use your plants.

But I do need to congratulate LGHT on his/her finally comprehending a basic rule: as you get closer to a light, the intensity (and the heat) increases.

Any fool who doesn't believe this can get in a spaceship and fly to the sun, taking measurements - in lumens, lux, foot candles - whatever you prefer, as well as the temps.

Mike

 

[LGHT]

But I do need to congratulate LGHT on his/her finally comprehending a basic rule: as you get closer to a light, the intensity (and the heat) increases.

Growing a plant in a closet is all new to me just as growing peppers are. I have taken on both task this year and have only been doing both for a matter of a few months now. However before I purchased any of my equipment I did put in I would say at least 20 hours doing research and even then still had a lot of help from sources online and guys here. The first article I read did mention that HID lights will produce MONSTER crops, but you have to get fans and exhaust to deal with the heat.

 

[hydrojunkie]

Don't take it personally wordwiz I wasn't trying to be a dick, but lght just did what I wanted you to do with his calculations. Now,who is gonna go with me to the sun to take some measurements, wordwiz I may need to borrow your meter but I make no guarantee you will get it back in working condition,its gonna be a trial and error test.

 

[qbvbsite]

Here is the facts and these can't be disputed. A bulb rated with 50K lumens produces ONLY 50K lumen no matter what.

1 lux is equal to 0.092903 lumens per square foot. So if you have a lux reading of 31000 it is giving you eprox. 3100 lumens per square foot. Each plant required 3000-5000 lumens per square foot depending on the stage (as stated in the table from LGHT).

Wordwiz you are wrong with the following statements

Lumens is the amount of light a foot from the source.

Incorrect lumens is the amount of light a buld gives out

So if a light is rated 7,000 lumens, at two feet away, one would get 3,500 lumens, at six inches 14,000. At three inches, 28,000. I might have been a bit closer than three inches, I didn't measure but guessed; I might have been 2.5"

This is also wrong you get 7000 lumens from the bulb no matter what. The only thing that changes is how much lumen per square foot you are getting depending on the distance. The closer you get the more lumens per square foot and the higher lux reading you are going to get.

 

[qbvbsite]

One more thing to add.. when getting a lux reading its assuming that you would get the same reading anywhere (within the metre square) if so then the following would be correct 50K lux = 50k lumens. Which would be a 400W that gives out 50K lumen and the grow area is 3.2' by 3.2' (aprox 10 square feet) giving you 5000 lumens per square foot and a lux reading of 50K). Now with a 400W light most people with make a 4' by 4' area which would give you 12 square feet of grow area, which equals to 4166 lumens per square feet which is still 50K worth of lumens.