New Growroom, need HPS wattage advice

I'm getting ready to set up a 4 ft x 6 ft x 6 ft tall grow room. It will have plenty of ventilation. I want to grow about eight plants at a time. I want to go with HPS lights but I don't know if the 400 watt will be enough or too much. I also wanted to use hps for veg and flower, any input????

Thanks much!!!!

I have a 2' x 4' by 5' and I'm running 600w HPS, you should have no problem with that in your area, you might even want to go a little higher if your ventilation is good


Good luck

I have a 1000w on a light rail to cover 4'x6' and i still feel it needs more light sometimes.
400w is not enough.

400w covers 16' square, 600w can cover 25' square. You have 24' square, which means a 600w light will provide 25W per square foot. That is near the bottom of the recommended, but for only 8 plants, should be plenty.

You can use HPS for both cycles, but if you do, consider supplemental lighting for vegging, maybe some cool white Flouros or daylight CFLs

400w covers 2'x2'
600w covers 3'x3'
1000w covers 4'x4'
so ya hope that helps

Dirtfree said:

I have a 1000w on a light rail to cover 4'x6' and i still feel it needs more light sometimes.
400w is not enough.

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Thats 41 watts per sq foot.... plenty of light for your situation. A 600w would do it. I hope you are getting the difference in bud for that power bill.

Serapis said:

400w covers 16' square, 600w can cover 25' square. You have 24' square, which means a 600w light will provide 25W per square foot. That is near the bottom of the recommended, but for only 8 plants, should be plenty.

You can use HPS for both cycles, but if you do, consider supplemental lighting for vegging, maybe some cool white Flouros or daylight CFLs

Click to expand...

A 400w will not cover 16'sqft or 4'x4'. Same goes for the 600w. I dont know where you got your numbers from but they are not suitable for growing MJ

Just get a Lumatek dual 400w digital ballast and do 400w hps and 400w mh, if you have the funds of course.

Dirtfree said:

A 400w will not cover 16'sqft or 4'x4'. Same goes for the 600w. I dont know where you got your numbers from but they are not suitable for growing MJ

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I got my numbers from knowing what I'm talking about. A 400w covers a 4' x 4' area which is 25w per sq'. That is common knowledge. One may wish to up to a 1kw light for that same space for flowering, if they can fill the entire canopy, that would be 62.5w per sq', which is more than adequate. Considerations have to be made for ventilation, heat, height from plants, power bills, etc. Some people aim for 50w per sq foot, but a lot of that is wasted unless your canopy is full. My numbers are more than suitable for vegging Marijuana. AS for flowering, that could easily be debated, it all depends on growing techniques.

My numbers come from Ed Rosenthal's Indoor Cultivation Handbook. Here is more online resources to verify my numbers.

http://www.cannabisculture.com/v2/articles/3204.html

He wants to have eight plants in a 4x6. So im guessing its going to be pretty full in there. I am currently running 6 plants in the same space, and yes im using every bit of the canopy, and still with out the right reflector or growing in a v-shaped screen the light efficentcy is not reaching the garden canopy the equally in the corners or sides. So your numbers sound good on paper but really they dont add up. And back to the OP's question, a 400w will not cover 6 decent size plants in a 4x6 space. Maybe if you hung the bulb vertical and placed the plants around, hey thats kind a good idea.

Serapis Im not here to argue man, so if you are lookin for a pissing match, I dont have time for it. If it works for you than great. But everything I have read so far says a 1000w light covers 4x4. I have only been dong this a couple years but I am still learning.

dirtfree has the numbers right.
id use 2 x 600 in there. i have a 6 x 9 and will be running 3 x 600, could even go more but need more exhaust first

the ones that get a bigger footprint have the light to far away. a 1k is only good for 24 inches so a plant more than that is a waste of bud

and i wouldnt even run a mh..i never do and no....there is no stretch...check the journal. running a few tests grows for nute co and seed banks

2x600W should cover that space rather well with space left to work on the plants.
But, if you wanted to hang the lights vertically surrounded with plants, 400's would work well for four plants each. In this arrangement, you can grow them tall. Imho, this seems like the best way to grow. My vert yields way more than flat ever did.
Fred

It is fine, I'm running 18 plants in the same space 4x6 with a 600watts hps light and they do great, I use 3 gal containers for each plant, good luck

One 600w is ok but two is better for that space. With the 2*600w that's 50w/ sqft. 62sqft is ideal.