Fan cycling

[CantBe2High]

I am on my second grow, have a small cab with a vortex fan. The fan is a bit louder than I'd like. For stealth and temp reasons I plan to have the lights on during the night when flowering (like 9:00PM to 9:00AM).

Would there be likely problems in odor, humidity, or otherwise if I only had the fan on when the lights were on? This would give me a bit better temps I think and more stealth. I have a digital temp/humidity measurer with memory so I can monitor things. So fans, only when the lights are on or all the time? Does it matter much?

 

[Guest]

Do you run hydro or soil? I am not sure about soil, but with hydro the humidity would go off the charts. In such a micro climate, constant fresh airflow is needed. Not just for expelling heat, but also introducing new fresh air rich in c02. Is this your only source of intake/exhaust? If so, think about adding a speed controller to the vortex. Without negative pressure ie.) your exhaust you will have odor problems in flower. I assume you are running the fan to a carbon scrubber or something of the likes?

you can always try and see what happens, but I don't think it would be beneficial.

speed controller ftw

 

[terminalc]

How do you have your fan mounted. Try mounting your fan suspended with bungees instead of screwed directly to the wall, it should reduce noise substantially. You could go further and add a duct muffler if you liked, and didn't have space constraints. It would be best to leave it on all the time it is good to have constantly moving air and water. If you run your lights at night then i don't see any problem shutting the fan off during the day with soil though. You might be setting yourself up for humidity problems that way.

 

[CantBe2High]

Thanks

Thanks

Growing in soil. Figured humidity and odor could be problems. Have a 4" Vortex inline fan into a charcoal scrubber. Negative pressure cab bringing in air from another room, about 4" wide, 4" high, 2" deep. Have 200W of T5s for veg and/or 400W HPS for flower. The 400W HPS was too hot for my grow over the summer, but in the winter I think it will be fine as nights are cold and its a closet/attic area. I may even try the T5s on the side and the HPS on the top for 600W. During flower I run the lights from about 9:00PM to 9:00AM. Right now just using the T5s and temps are between 65 and 85, and the high is going down daily as fall/winter sets in.

The scrubber and fan is in an awkward area of the attic though where better mounting would be hard to install. Right now its laying on a flexible AC duct that does muffle it some, so its kind of laying on a bouncy pillow. Thought about bungee cords or something suspended. Maybe I can rig that up or move the fan farther from the charcoal can. As its an attic type area in the winter temps are not so much a problem -- low temps at night but that is when the lights are on. The whole setup is somewhat cramped for space, which is part of my problem.

I may make one more attempt to quiet the fan. Its not that bad, but when in the room its a bit noticeable. Its a seldom used part of the house so not a big problem. But since I have a digital temp/humidity sensor with memory I can always try it for a few days and see what happens. But tend to agree constant airflow is likely the best bet.

 

[Tony Aroma]

I grow in a double-wide wardrobe, in soil, and just keep my exhaust fan on when the lights are on. The main reason I do this is noise. It's not the fan per se, but the rushing air. I've done everything I possibly can and cannot get it any quieter. I do however keep a small fan on for circulation inside the cabinet 24/7.

I don't know if this lack of fresh air hurts the plants any, since I don't have a basis for comparison. But my plants generally seem happy and healthy. No mold problems or anything associated with high humidity.

As far as odor when the exhaust is off, that's a different story. My last crop was very low odor, and I never noticed anything outside the cabinet when the exhaust was off. This time around, about 5-6 weeks into flowering I started noticing a slight odor outside the cabinet. So I guess it depends on what you're growing and how air tight your cabinet is.

One other thing, as a warning. I tried at one point having the exhaust fan and lights on separate timers (to suck some fresh air in when the lights were off). When I switched over to 12/12, I screwed up setting one of the timers and my plants went about half a day with lights and no exhaust. So now my fan is either on all the time or on the same timer with the lights.