redeyefly

I have almost established a good grow technique but have a few questions regarding the best light combinations for my garden. Is it better to use (2) immobile 400W HPS or (1) 1000W HPS on a track for a 4' x 8' area? I ultimately plan to build a grow area of (4) 4' x 8' areas and want to buy lighting for the future. Right now I only use (2) 4' x 8' areas. So, in the future, should I go with (8) immobile 400W HPS or (4) 1000W HPS on tracks. I already know it would be materially cheaper to go with 1000W except for lamp replacement. It would probably be cooler to go with the 4 1000W also. I suppose the electric bill would be about the same with both methods. However, regarding even light distribution and intensity, which would be the best combination? I appreciate any replies.

lilbud99

Hi Redeyefly Welcome to H.C

Have you considered 600w lights......they offer more efficiency than 1000w lights if used in mutiples....if you consider the following....

1 x 600w = 90,000+ lumen ..... 2 x 400w = 80,000+ lumen 1 x 1000w = 120,000 lumen....and interms of running cost's, 6/10ths of what it would cost to run a 1000w saving you a lot of $$ over a year or more..... and the lamps are cheaper to replace too

a 4x8 area gives you 32 sqft..... so with 4 x 600w (2400) you would have 75watts per sq ft......a good amount.....most people strive for around 55/60 per.....for optimum growth.... you may not have so much of a heat issue with 600's aswell compared to 1000watters which would effectivly give off 1kw of heat as well as light.

Lilbud.

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redeyefly

{Admin Edit} Threads merged.

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redeyefly

So, are you suggesting that (4) 600W HPS on rail light movers, (1) light over each 4' x 8' area, each light offering some supplemental lighting to each of the other areas with the assistance of mylar reflection enclosing the area in about a 14' x 18' area is better than using (4) 1000W lamps in the same configuration? I'll be burning 2400W for 12 hours instead of 4000W. I see the watt consumption advantage, but am I maximizing intensity for all my plants? When using rail light movers, some plants (the ones at the far ends usually) are exposed to less levels of light than most as the light moves. At the furthest point, the light would be approximately 7 feet away from the end plant. With this in mind, would 1000W be the better or will 600W still be the most efficient? How many lumens would reach the end plants with each lamp type? I know I am probably beating a dead horse but I want to be absolutely sure before making a large light investment. I already own (1) 1000W and (2) 400W. I look forward to any replies. Thanks.

arnold layne

a 1k will throw more light than a 600.
the lower wattage lamp can be placed closer to the plants without as much heat as a 1k, so that is one benefit of the lower wattage.
a 600w has a higher lumen per watt ratio, i believe, therefore it's more eficient.
you will still get more light from 4 1000's than you will from 4 600's.

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redeyefly

Let's say I have a utopian garden with the obvious restrictions still applied i.e. legal constraints. Using CO2 and all other bells and whistles. Would I be using (4) 1000W HPS or (4) 600W? I just reviewed a thread that implied CO2 plus intense light = high yield. So I guess the ultimate question would be, setting aside cost and heat issues, which of the 2 configs would result in the highest yield? This is for a 18' x 14' area growing 128 medium size plants (3' to 4' tall).

lilbud99

Sorry to confuse the issue....I re-read your original post and I noticed its more than one 8' x 4' area

Do you have the circuitry to allow for 15amps per 1000w light on your electrical supply....this would be my concern.....

Dont get me wrong....they will certainly give off more light, & if you have no concerns over heat/ventilation/cost Its probably the better option for you....as long as your electrics are upto it....

I stand by what i said about 600's being more efficient, they are....and would be my choice for an area of your size.....simply for the running cost's and heat control..... the canopy penetration is upto 6"/8" less than what you would get from a 1000w tho.

If your looking at possible Co2 use aswell, the higher light and heat outputs can definetly be utilised to your benefit.....have a browse thru the forum with the search feature.....its all in here somewhere's

LB

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vernonsupreme

get a .6k digital, it produces within 5% of the usable light of a 1k coil ballast light. and uses 40% less power.

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penguin

That's 32 square feet and you will need at least 1600 watts to light it adequately. Depending on the varieties you plan to grow, you'll probably get better results with 75w/sf, and you can run up to 100w/sf (or more).

18'x14' = 252 sf * 50 w/sf = 12,600w as a practical minimum to light the space you are planning.

It doesn't really matter what wattages you run. 1000 w has better penetration and allow taller plants), but more, smaller lights produce better distribution (footprint); smaller lights don't penetrate as effectively so the canopy can't be as deep. For a given total wattage, similar yields can be produced on a gram per watt per month (g/w/m) basis. In other words, 5 x 400w and 2 x 1000w can produce approximately the same amount of bud. Keeping all of the lamps in a room the same wattage has been easier than mixing wattages, in my experience.

Different lamps have different luminous efficiencies, but luminous output has no bearing on plant growth efficiency (in other words: lumen ratings aren't useful for our purposes). So although a 600w Hortilux has much higher luminous efficiency than 400w or 1000w Hortilux lamps, that does not necessarily mean that it's more more efficient in terms of producing light that is actually useful for plant growth. In order to make a fully educated decision about which luminaires are more efficient, you need to consider the total radiant power (output, in watts), and how well that power is distributed relative to the action spectrum of photosynthesis.

Light movers do not reduce the w/sf requirements. They do increase the footprint of the light, and allow more plants to be grown, but don't improve g/w/m in underlit spaces. For example, a stationary 1000w in 12 square feet will produce as much or more than 1000w on a mover in 24 square feet. Unless the room is already extremely well lit and the goal is to eke out every last drop of yield, it's usually better to invest in more stationary lighting, rather than a light mover. In "optimally" lit spaces (75 - 100w/sf), movers increase the effective penetration of the lamp, allow a deeper canopy, and so improve yield. Movers would also allow you to run obscene amounts of light (>100w/sf) with less risk of damaging the upper canopy.

Plan on at least 3 BTU of cooling capacity for every watt of lighting (also regardless of individual lamp wattage).


penguin

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BaadPuTthyKat

I can't add much to what Penguin's encyclopaedic post has put....but... I think that 2 x 600W HPS is a bare minimum for 8ft x 4ft.. The heat load above this wattage means you need to really consider investing in large air movement & carbon cans quite early...especially as you are (I assume) going to go for optimum lighting of ~70w/ft2, and multiple bays..

A mover could be used to supplement stationary HPS's with a MH, but a point of Penguin's post I think was many lights & smaller plants is more efficient.. Height adjustment of lights is an efficiency essential as well, and it can get too complicated up there... Keep it Simple.

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