It all depends. How many square feet are you going for?

Hi -

Under the 1000 the coverage area is about 6x6

Under the 600 the coverage area is about 4x6

Under the 400 the coverage area is about 3x6

does that help?

Thanks!

Depending on Price...if you can get 2 400s for the price of one 1000 then you are better off, using less wattage and covering the same area and maybe slightly more.

Not sure a "final answer" is actually possible, because there are so many, many variables -- everything from "what" you are growing, to the size of your garden , to the "stage" of the plant.

What I am about to say may not be new to you and I will apologize in advance if I am repeating some of what you already know

First, Full Disclosure: Before I stumbled on GW I happened to stumble on some Marijuana grow sites. I'll share a little secret with you; despite the moral and legal issues, there are a number of "potheads" out there who truly know a lot about soil, grow lights and gardening in general, and I will admit I learned a GREAT deal from that source.

Regardless, I'll be brief and (hopefully) answer your question...if possible.

First, acknowledge that with grow lights you are trying to imitate the sun. The inherent problem is that unlike a light bulb the sun is in a constant state of change - of color, intensity and # of daylight hours.

As to color, the HPS gives puts out a different color spectrum than MH....which is different than FL or CFLs.
Choose the wrong bulb and you may be telling it to bloom when you want it to grow - or vice versa

As to intensity, you will have a problem with heat LONG before you have too much light. It is simply not possible for a "bulb" to put out as much intensity as the sun - so you look at the "minimum". As a rule, and depending on the plant, most indoor growers say that 50w per sf is the Min. for vegetative growth (for HID, not Flouros), so if you have a 3x6 area, or 18sf, then you need 18 x 50w, or 900w for a 3x6 garden.

As to daylight hours, many if not most plants are triggered by not only the color spectrum (which changes with the season) but the number of daylight hours as well. This may not be a large determining factor in bulb purchase, except that the different type bulbs have LARGE variations in lifespan. I mean, a LARGE span difference

Then of course there is price. Not just the price of the purchase, but of power consumption. If you subscribe to the 50w per sf rule, 2 400HPS will cover less garden than 1 1000w, will use more power and may not be such a bargain after all

So, the "Final Answer" is - "It Depends"
You need to make a few decisions - on what you are growing, the size of your garden etc, etc....and THEN you will have the "Final Answer"....at least for you and what YOU are doing.

Hope this helps

Thanks to all for your replies.

I am growing:

1) Madagascan succulents, many of which go dormant in the winter
2) South African succulents, some are winter growers
3) a few small cacti
4) various tropical (e.g., ficus) and subtropical (european olive, Brazilian raintree, jaboticaba, buttonwood) bonsai
5) a few cycads (cycas revoluta, encephalartos horridus, zamia)

I usually buy the Sunmaster bulbs (blue burning MH, and the Sunmaster Super HPS), but I was wondering if ($ being no object...) there was a better, higher performing choice (see coverage areas in my earlier post). The HPS seems to burn brighter (as measured in footcandles with a meter that I have) and penetrate farther down toward the ground. The MH have a bluer output, but don't seem to burn as bright.

So, are their better bulbs available considering my setup?

Thanks again!

T

as a real grower, with an actual yield measured in KILOGRAMS of WEED, that I put out on a regular basis, and having studied this field as only a pathologist could, you need:
Reflectorized HPS - buy it from HTG supply, you will be very pleased with it. My own personal grow op does actually match the intensity of the sun: I measure 10,000 foot candles at the level of my canopy, which i blast my plants with in the final 4 weeks. For YOUR application, one 400W HPS reflectorized lamp is probably lots. As a BONUS, your HPS ballast will also perfectly run the CERAMIC METAL HALIDE, which in YOUR application will also do a beautiful job, but you need a reflector: buy a good one, such as a LumenMax: again I guarantee you will be happy.

klinko -

I admire your yield levels ;-)...

and have a few questions based on your reply.

My setup is:

400W Metal Halide
600W HPS
1000W Metal Halide

So, I can try out the 600W Reflectorized HPS (any brand in particular?) on my HPS setup.

But, I don't believe that a 600 Watt Ceramic MH exists, does it? Only 400W, correct?

What do you recommend for my 1000W Metal Halide and my 400 Watt Metal Halide? Any suggestions?

Thanks!

T

"reflectorized" hps lamps come out of one factory in China, and they are available from HTG supply, for pretty cheap.

ask your local hydroponics store person, if they could take out the "guts" from ur metal halide ballasts, and replace them with HPS. this should save a considerable amount of money, and you will be able to run HPS which is the preferred light for pot growers. or you can buy the "kit" urself from
plantlightinghydroponics in indiana (businesslights.com). they will ship you the innards, and you just replace, it is very simple, and comes with a diagram. that's what i would do.

klinko16 10,000fc is a little short of the sun. Did you mean 100,000?

In my experience, plants grown under only HPS, even 1 ft. under a 1000 watt bulb, will badly sunburn when placed in direct sunlight. Apparently, blue or violet light is necessary for plants to develop the pigments that protect them from sunburn (sort of like a tan). For that reason alone, don't use HPS for "overwintering."

http://cactiguide.com/article/?article=article17.php