minimum closet or cab size

whats the minimum size (height/width/depth)
for a cab using a 400 W HPS
small grow, only like 2-4 plants flowering

also, minimum fan speed suggestions for intake and exhaust vents.
thanks

I would like to know as well as i am making a grow room soon and haven't really put much thought into the size of my grow 'cabinet' for about 5 plants. For the fan you want something that will replace the entire volume of the grow area 2-3 times a minute. So depending on how big it will be (hopefully someone can help out with that).

Am i right in saying: CFM stands for Cubic Feet Minute, since i use metric units (Metres and Litres and all that) I'd Go Width x Lenth x Height to get Metres(cubed) to = Litres(cubed) and times that by 2.5 (2.5 as its in-between 2 and 3 times to replace the amount of air)to get how much volume i need to remove-...Convert that into cubic feet using google?

Very interesting. But I would suggest that you need to first convert the cubic meters to cubic feet, and then multiply the volume in feet x 2.5. This would be most accurate.
As well, there is no need to convert to liters. Cubic meters is fine for measuring volume
See, we both helped each other here.

Just curious, where'd you get that formula from, that you need 2-3 times ?

My friend who has gone on year leave has been growing his vegetable for 2-3 years and told me that i should extract about 2x my working area, i wasn't so sure, so i went on the net and found this: Which under the ventilation section says 2-3x, so that kinda put that idea in my head for when it comes to me planning my equipment http://howtogrowmarijuana-cannabis.blogspot.com/

^^

"The power of the extraction system you need is determined by the size of your growing space. You will need a system that can remove the volume of your grow room 2 or 3 times every minute. First you need to calculate the volume of the growing area then purchase a fan with enough power to remove this volume of air at least twice per minute."

Click to expand...

Which under the ventilation section says 2-3, so that kinda put that idea in my head for when it comes to me planning my equipment \

P.S what size is suitable (between) for a Growlush 400w HPS - 62,000 lumens, with a 400w Growlush Ballast, Reflector + Walls lol
Thanks

ok.. sounds reliable.
as far as your question for your growing space, i have no direct answer. its kind of what i was asking, and i think it boils down to what kind of lighting you are using. for example, the heat generated by 250 watts of CFL's i am assuming would be considerably less than that generated by 250 watts from a HPS bulb. but hey, someone correct me if i am wrong...

you could grow a handful of plants in an area thats 0.5m x 0.5m x 0.5m with 4inch vents using 150 Watts of CFL's, and you wouldnt want to do that with 150 watts HPS, from what i hear from other people. im not an experienced source though

Ignore this. I double posted.

lochem said:

the heat generated by 250 watts of CFL's i am assuming would be considerably less than that generated by 250 watts from a HPS bulb. but hey, someone correct me if i am wrong...

Click to expand...

You're wrong.

Energy in lighting systems gets converted into 2 things: Light, and heat. More of one means less of the other. Since HPS are more efficient than cfl, they put out more light, and therefore less heat, than the equivalent wattage of cfl.

Cfls just feels cooler up close because of their larger surface area, and the type of heat emitted (convected, rather than radiated). Overall though, cfls create more heat.

lochem said:

you could grow a handful of plants in an area thats 0.5m x 0.5m x 0.5m with 4inch vents using 150 Watts of CFL's, and you wouldnt want to do that with 150 watts HPS, from what i hear from other people. im not an experienced source though

Click to expand...

You could easily use a 150 hps in that area, although more height would be preferable, more for logistics than heat.

inhale, exhale.
double post

djj,
i just took a peek at an exhaust vent. the specs are: 4 inch diameter, 2500 rpm, and extraction: 98 m^3/hour. which translates to (98/60=) 1.63 m^3/min
thus, for a space 0.5m x 0.5m x 1m, whose volume (in cubic meters) is 0.25, such vents would be more than enough, according to the formula you quoted from that site.


regarding my other comments.... :

Nocturn3 said:

You're wrong.

Energy in lighting systems gets converted into 2 things: Light, and heat. More of one means less of the other. Since HPS are more efficient than cfl, they put out more light, and therefore less heat, than the equivalent wattage of cfl.

Cfls just feels cooler up close because of their larger surface area, and the type of heat emitted (convected, rather than radiated). Overall though, cfls create more heat.


You could easily use a 150 hps in that area, although more height would be preferable, more for logistics than heat.

Click to expand...

hey, thanks for that reply. im glad someone was so quick to correct my n00b assumptions . . .

now since you're here, how about this Q: is a space like that OK for a 250 w HPS ?
and how do you feel about this formula postulated by djj? (the recommended extraction abilities of a vent being 2-3 times of the volume, etc)

Not sure about the formula, but I believe that the minimum you should aim for is to exchange the entire volume of air every 3 minutes. This is just to ensure that the plants have enough fresh air, and doesn't take into account heat gains from lights etc, so in reality you would want to exchange more often, especially as you go up in wattage of lights. If you need to add a carbon filter or ducting, the number would rise again, since restrictions of any kind will reduce airflow.

As an example, my 250 HPS setup uses a 4" fan rated at 175 cfm. It's fast as fuck on it's own, but once I added the carbon filter and around 1 metre of ducting, with 2 bends, it gives me good airflow without being overkill.

As for your question on lighting, 2x2 feet is perfect for a 250 hps, 3x3 for a 400, and 4x4 for a 600. Height required varies depending on your growing style (scrog, for example, requires less height than untrained plants), but more height is generally desirable. I have about 6 feet of vertical space in my setup, but only use around 3 feet, since I am running a scrog.

Hmm interesting. Out of interest what do you think the best deal is out of these I have a $500 budget for everything i need not including electricity or water costs lol
400W Deals:
1. http://cgi.ebay.com.au/400W-HPS-HYD...Seed_Starting_Hydroponics&hash=item4aa624e3b3
2. http://cgi.ebay.com.au/400W-MH-HYDR...Seed_Starting_Hydroponics&hash=item3362696a48

600W Deal:
1. http://cgi.ebay.com.au/600W-HPS-DIG...Seed_Starting_Hydroponics&hash=item4aa624b78b
2. http://cgi.ebay.com.au/600-WATT-MH-...Seed_Starting_Hydroponics&hash=item335acb3b0c
3. http://cgi.ebay.com.au/HPS-600W-Kit...Seed_Starting_Hydroponics&hash=item4aa3f997cb
4. http://cgi.ebay.com.au/HPS-600W-Kit...Seed_Starting_Hydroponics&hash=item4aa3f997cb

I'll build my own tent-wood i can get free. 1.2m x 1.2m x 2m for both 400 or 600W alternatives.
I'll buy a carbon filter, in and out fan duct & Fan, soil probably $50? PH - $13, Timer U8 $36



any ideas would be great/alternatives that add to $500 if you feel like it thx

wish someone could have told me that young seedlings have no place under a 250 watt hps.... all they do is shrivel.