What size light?

[noobie97]

I am about to build a grow tent type enclosure at 4x4. My concern is I only have 3.5 ft. vertically. Would I be able to pull of an air cooled (cool tube) 1000 watt? Would a 8" 600 cfm fan suffice?

Planning to do a sog grow, with perhaps a soil bed or some type of tub to conserve vertical space.

 

[Tyrone Hamilton]

You'll have to go 12/12 from seed with that headroom - I'd use a cooled 600 at most. The fan sounds fine. You might look into CMH bulbs for less heat... but they only go up to 400.

 

[Screwnuts33]

With 3.5ft of headroom a 1000watt is a waste and will fry your plants. Look at a multi-bulb T5 setup.

 

[noobie97]

How about a 4x3 with a 600..will that be enough watt per square foot?

 

[Malcolm]

SOG method would work well. You have 16sq ft of floor space which would accommodate enough small containers to make it worth while, I would use square containers to maximize every available inch of floor space. For lighting I would go with an air cooled 600watt HPS with an electronic ballast to minimize heat. Also, it will use less electricity the the standard lead ballast. The plants may stretch just a bit under the HPS lamp but you can use it from start to finish with good results. They do not manufacture a 600watt lamp in MH, only conversion bulbs which cost more. Be sure to have the proper amount of intake/exhaust cfm's (cubic feet per minute) to remove and replace all of the oxygen within the room. The normal time frame for this important transformation is every five minutes which means that all the air in the room should be replaced every five minutes with fresh clean air (co2). I guestimate the cubic footage of your space from your dimensions, at about 48-50cf. With this amount of space, the intake/exhaust system would not have to be that extensive. Hope this helps...

 

[Proliferation]

4X4X3.75 = 60cubic feet. A 600CMF fan is big time overkill!

You want your fan to change air in the room within about 2-3 minutes as general rule of thumb.

good luck

 

[Tyrone Hamilton]

4X4X3.75 = 60cubic feet. A 600CMF fan is big time overkill!

You want your fan to change air in the room within about 2-3 minutes as general rule of thumb.

It does depend on the light though and ambient temp - more light = more heat = more air changes. I have to change the air about twice a minute in my closet to maintain mid eighties.

Also, I like to run my 474CFM fan at half speed to keep the noise down... I had a 4" fan that was adequate, but sounded like a hairdryer.

 

[Proliferation]

good point. i had not really considered its a closet type set up

 

[Malcolm]

4X4X3.75 = 60cubic feet. A 600CMF fan is big time overkill! You want your fan to change air in the room within about 2-3 minutes as general rule of thumb.

good luck

Just because the room is 60cf does not mean it will require a fan of that capacity. I do not follow your logic on this one?...

 

[Proliferation]

Just because the room is 60cf does not mean it will require a fan of that capacity. I do not follow your logic on this one?...

I didn't say it would require a 60cfm fan, just that the room was 60cf.

if you use the logic that you would want to clear the room within 2-3 minutes (also previously mentioned) than less then 30cmf fan would do the job. Again, not sure where you misinterpreted the comment but hopefully that clears it up.

and that was just basic rule of thumb for sizing a fan by CFM. This was not considering the size of light and additional heat generated from growing in small space like a closet as mentioned by obxgardener above.

 

[Malcolm]

4X4X3.75 = 60cubic feet. A 600CMF fan is big time overkill!

You want your fan to change air in the room within about 2-3 minutes as general rule of thumb.

good luck

The "capacity" I was refering to was the 600CFM (cubic feet per minute), fan you mentioned. How did you determine that a room of 60cf would need a fan that size?...

 

[Proliferation]

The "capacity" I was refering to was the 600CFM (cubic feet per minute), fan you mentioned. How did you determine that a room of 60cf would need a fan that size?...

I didn't. If you read the first post you will find the individual mentioning the use of a 600cmf fan...which I said would be overkill. did you read the posts, carefully? I think if you read this start to finish you will find all your questions answered.

 

[ol hippy]

For that size room I'd think that a 400 watt hps would be enough.Anything more gives you a heat problem. Sure you could use a huge fan to cool it but why go through all that just get a 90-100 cfm exhaust fan and stick it in the ceiling and vent it to the attic.

 

[Malcolm]

I didn't. If you read the first post you will find the individual mentioning the use of a 600cmf fan...which I said would be overkill. did you read the posts, carefully? I think if you read this start to finish you will find all your questions answered.

I'm glad we cleared that up...