Indoor Need some advice on picking light for closet grow

[IZNICE]

Hi getting ready for my first closet grow. my closet dimensions are 39"W x 19"L x 91"H. i plan on putting a shelf in the middle and splitting the closet in half and starting 2 plants in the bottom half under cfls then moving them to the top half under a 250w cmh for the last month while i start 2 more in the bottom. My question is is the 250w gonna be to much or should i get a 150w? thanks Any other advise you have would be great to i will be starting a grow journal as soon as my seeds arrive

 

[grindin]

whatever you choose id try to go something without the built in ballast. I have a 400watt and 150watt sun systems w built in ballast and the ballast gets hotter then the bulbs.. also what you using for exhaust and intake?

 

[IZNICE]

yeah im gonna get a remote ballast no matter what. as far as intake i am using pc fans and the exhaust i am gonnna use either a 4" of 5" inline fan with carbon filter and exit thru the ceiling of the closet. I just wanted to know if 250w is my best bet or is it gonna be over kill for 2 autos

 

[Hermitian]

To answer your question directly: if your bulb is 1 meter above the plants it will be a bit on the weak side. Here's the details:

Ideally, you will have a minimum of 50 W and maximum of 75W output per square foot at a distance of 1 meter above the plants. The "footprint" of your closet (or shelf) is 39"x19" ~= 5.1 square feet. Multiplying that by 75 W/s.f. yields about 383 W. Multiplying 5.1 s.f. by 50 W/s.f. yields 255 W.

The wattage rating on the lamps is current draw, not effective output in the spectral range used by plants.

• The cfls has an effective output of about 92%, so for these you are looking for a set of bulbs with a total current draw between 275W and 415W.
• The cmh are much less efficient in the output of usable light -- somewhere between 15% to 30% of the output is a combination of long wave and heat, with the smaller wattage bulbs (~200W) being the least effective. You would need a mid-range bulb which will have about 78% effective output. Therefore, you are looking for a cmh bulb with a current draw between 325W and 490W.

 

[IZNICE]

Thanks so much just wanted to make sure i was on the right track (hate wasting money due to ignorance) The only cmh bulbs i can find are the phillips mastercolor retro and that only comes in 250w and 400w so u r saying i should use the 400w if i wanna go with cmh? I am leaning towards using cmh cause i heard nothing but great things about them on this and a couple of other grow forums i have been visiting. Should i just get a 250w hps and be done with it?

 

[Hermitian]

You need to decide what bulb technology you wish to use, then purchase the appropriate amount of wattage.

Cannabis and many other plants perform best with intense but diffuse sunlight.

• In terms of meeting plant requirements, the best source are the 6500 Kelvin T5 HO bulbs provided you implement enough wattage. If you purchase them from a contractors' supply store (not Home Depot, etc.) the cost is very reasonable.
• It is true that people get good results with HPS, CMH, etc. They emit a partially coherent (non-diffuse) light and a lot of heat. The latter might be helpful in some situations. If you track these bulbs back to the manufacturer (Philips, GE) you will find they are engineered as a supplement -- not a sole source, for outdoor greenhouse applications where extra wattage is needed. Now of course there is fancy Cannabis packaging on the bulbs sold in hydro stores, but this has been added by distributors like HydroFarm.
• Growers have been experimenting with LEDs for awhile. At present, they are the most expensive option per effective Watt.

 

[agito]

I think 150w hps would be to small me i would either go for a 250w min as 150w would not give you that much light for flower

 

[TshirtNinja]

im going to recommend you get a 240w blackstar panel to finish out your 2 plants. low on heat and high on yields for me.

 

[AutoMan]

IMO....been there, done that with a closet.....heat control is gonna be a huge issue....I was forced to move mine to avoid butchering my grow area....Never used led but with the low heat footprint, I'd def be looking at it....good luck to ya...

 

[Joe Dirt]

If you can afford the LED's recommended by Tshirt, that's definitely the best way to go due to the heat issues you will face. As Automan says, closets present serious heat challenges and if you overlook them, you'll probably sacrifice your whole grow.

That being said... I have been growing in an almost identical situation. I can't/couldn't afford the initial expense of the Blackstar so I have a 400w HPS. To deal with the heat, I place a 12" oscillating fan on the floor that blows cool air from the closet doorway, toward the pots/bags to keep the roots as cool as possible. I have a 16" pedestal fan that I have blowing the air in between the canopy and the reflector, and a 5000 cfm floor fan, mounted on the top shelf of my closet, blowing out the door for exhaust. This keeps my temps about 10 degrees above ambient temps.

It is a far less than desirable set-up and, thank God, I was just able to create a better situation for myself. But, if a closet is all you have, it can be made to work.

P.S. Just because I have a 400w HPS doesn't mean you need one. If you only plan to flower two plants at a time, you can easily get by with a 250w HPS... or maybe even the 150w. One thing I would consider if I were flowering two plants at a time is a 105w cfl per plant. That would give you enough light and you could adjust the height of the fixtures independently.

Here's a link for higher wattage cfl's: http://www.1000bulbs.com/category/500-watt-equal-cfl-compact-fluorescents/