Help!! Its so hot!!!

eight five is ok just don't go any higher unless supplementing co2good luck

 

Yea Baby - its getten hot out there..

What is the dimensions of the room.
You should have a fan large enough to do 5 exchanges per minute.
Fan should be oriented to SUCK and not BLOW (try pushing a string)
Fan should be as high as possible.

 

I have heat issues as well. Check out my thread below and see what I had to do.

Stepdude420

 

I'm a first timer My grow room is 4 feet x 3 1/2 feet by about 8 feet high. Although I had a 4" inline fan sucking over the 400 w light, my temp ran high.

I broke down and put in a $99 air conditioner that operates in a small room in the attic, in which I suck the AC air into the grow room when the temp gets high.

This provided a cool 75 degrees with relative humidity running between 40 to 60 (the AC brings humidity down to 40 and when the temp goes to 78degrees the humidity may have reach the 60 mark by the time the AC goes on again). I was running 24 veg hours a day but cut down to 18 hours due to our Cali heat wave (light off during the hottest parts of the day). 

That's what was necessary for the right temp in my grow room. Never would expect it from the books I've read.

My question: I have some fuzzy mildew so I need to keep the humidity down during lights out when the AC doesn't run that much. Should I get a Peltier dehumidifier? It would have to be real small. Do they work at all?

Btu...I sprayed a 10 percent solution of whole milk to water and that seemed to take care of most of the mildew. Can burning suffer work in a micro environment?

420psych

 

hey man i have the same situation, i put in my new 400watt mh/hps (same one as yours) about 3 days ago. my plants love it but the temp went up to 85-90! i didnt have the money to buy a new vent system yet so i put in a house fan that sits on the ground and cranked it up to pull air out. its not much but it got my temps down to about 82

 

It's amazing how much heat builds up in a micro grow room. In all the books and mags I've read no one gave notice on how difficult it is to manage heat without AC. They make it sound like venting the light and room is adequate enough.

I tried my "room venting system" for heat and humidity. When the AC is on the room venting system (sucking out inline 4" fan - about 280 cfm) turns on (it's set to turn on for 1 min every 15 min for fresh air/co2) the temp goes up along with the humidity. Without the AC I always ran at least 10 degrees hotter that the temp outside the room no matter how much I vented.

I'm trying the room vent system with the light out to see if I can use it to rid the humidity when the the AC and the light are off.

I'll let you know what I find.

 

1. I don't think this counts as a Micro Grow
2. If you had a full cool-tube, i'm betting that you'd see much lower temps. Even if you had an open-ended one you would see significantly lower temps. Seems that your light is mounted with an econowing reflector, the air being pulled from the socket end of the bulb. the problem is that you're not actually exhausting the air over the bulb, just pulling l it from the socket area...not a whole lot more effective than simply exhausting from the top o the cab

 

Is the 250 CFM venting the room or cooling the bulb?

4X4X6 = 95 Ft3 X 5 = 480 CFM.
If the 250 is venting the room it is under-gunned.

 

The first thing I notice is that you have a lot of bends in your ducting. Try to make it as straight as possible, as rigid as possible, and as short as possible. Bends in the duct and movement of the duct itself reduce air flow. Stretch the duct as much as you can. This opens it up a bit more and makes it more rigid.

If your temps went up when you added the intake fan, then it is more of an obstruction than a help.

Your cool-tube rocks! But obviously something is wrong. What is the ambient temperature outside the grow room? You may need another fan, inline with the existing exhaust fan, to help pull the air. Perhaps this 2nd fan could be placed at the exhaust point in the attic. Or you may need a/c.

The general rule is that the intake should always be greater than the exhaust, because there are obstructions to airflow (called "static pressure") within the system. So, the diameter of the intake hole should be larger than the diameter of the exhaust fan. People usually say the intake should be 2x the exhaust. So, if you have a 6" diameter exhaust fan, you should have two 6" intake holes. This might be overkill, but it will ensure that you have enough intake.

Similarly, if you were to have two inline exhaust fans, the first fan (the one closest to the light) should be more powerful than the second. This is because the first fan is acting as "intake" for the second fan. How much more powerful depends on the static pressure between the two fans (ie the length of ducting and the number of bends). The main idea is that you don't want one of the fans to be more of an obstruction than a help. Having said that, I think if you got a similar fan to the one you have and put it in the attic, it would definitely help.

I just looked at your pics again. You want the first exhaust fan to be as close to the light as possible. Ideally it should be mounted on the tube.

 

Sorry, Mont, I didn't see your last post. But maybe I answered your question? Whether or not you need an a/c depends on the temp outside the grow room. What is it?

I would try a second fan before adding a/c because a fan is cheaper to buy and operate, and less noisy. Shortening and straightening your ducting is free (except for your labor!), so do as much of that as you can!

 

Sorry for so many posts, but I may be wrong about the exhaust rules when it comes to cool tubes. Your intake on the socket end of the tube is obviously smaller than the exhaust, because the socket itself is an obstruction, but maybe this is not a problem -- I've seen other people do it the way you have it.

Perhaps you could improve temps with a different kind of reflector -- one that has a glass lens on the bottom, and a 6" hole for the intake. It would be less restrictive.

Another option would be to use 6" ducting and a 6" tube. This would definitely increase airflow.

But I still think the first thing to try is a 2nd exhaust fan. If you have to upgrade to 6" ducting you can still use the 2nd fan.