humidity and thermometer controllers fans etc

[morphine34]

Hi folks,

 

Well my stealth closet is just about finished is coming along nicely (although at 1.8 metres high I’m realising its not leaving a lot of room for the plant to grow what with a carbon filter inside at the top and the lamp underneath that but hey I’m not that heavy a smoker so anything is good for me. When I do come across a good cheap big closet I think I will set that up but in the meantime Im happy.

 

What I wanted to pick your brains about however is the issue of humidity. I have a 6 inch exhaust fan pulling air through the carbon filter which seems to work ok and is not too loud. I have 4 passive intake holes cut into the floor of 3 inches diameter each so altogether that’s about double the 6 inch ducting the exhaust fan blows out through.

 

My concern is that I have the setup in my shed which being that I live in Melbourne is at the moment pretty damn cold and very high humidity. Im getting readings on my humidity thing saying 96% at night. And the bugger thing is it gets 40 degrees plus in summer so yes I know what you guys out of Melbourne are thinking – stupid place to live!

 

I think the heat from the light in the closet will evaporate most of the humidity that comes in but short of putting a heater in the closet for lights off I think ventilation will just keep pulling in damp air. So I’m guessing that my best bet for dealing with this will be to find some way to reduce the humidity in the shed.

 

Has anyone else had this problem before and how did you deal with it?

 

Another question – I bought a thermometer/actuator thing that senses when the temp is getting too high and can turn on the fan to exhaust the heat etc. However, I would like the same fan to run when lights are off on a timed basis to provide ventilation and hopefully keep the humidity down. If I have the thermometer setup to turn on the fan when the temp gets over 28 degrees for example, and a timer connected to that – its not going to work when lights are off because the temperature obviously wont be that high. I tried to find a combined thermometer/timer but have not been able to find one. One book I read suggested that I should have an exhaust fan for lights on linked to a thermometer and another fan linked to a timer for lights off – but this seems a bit over the top.

 

At this stage Im guessing that I will have to do some testing, dispense with the thermometer thing and find a timer sequence on the fan that works for keeping the heat at a reasonable level and provides sufficient ventilation for lights off.

 

I hope that makes sense – your thoughts?

 

Cheers,

 

Morphine

 

PS – If I havent already I will put up some photos soon

[The Hash Nibbler]

Hey Morphine, what temps are you getting in the cupboard at night? With your lights off should be around 20c. If it is going way down maybe consider putting a heater near the inlets to pump in warm dry air, and a fan to exhaust it maybe if the cupboard gets too warm. Might not be too big a deal to have the humidity high at this point but unless you want mouldy buds later try and sort this problem now. You could always bypass the timer with a twin power adapter like I do with my heat mat so it stays on at night when temps drop, just put it in before the timer and hook your fan directly to this, that way it runs 24/7. a double fan set up and timer for the lights off fan would be the best. Play around with it a bit and just keep measuring humidity and temps until you get it right, every enclosure is different, flows air different and holds humidity different.

Will help if I can but experimenting will usually give you the best results, you know your set up better than any one else =).

Great to see another cupboard grow. Good Luck and maybe someone else has some better advice =). Laters. GH72

[morphine34]

Hey Morphine, what temps are you getting in the cupboard at night? With your lights off should be around 20c. If it is going way down maybe consider putting a heater near the inlets to pump in warm dry air, and a fan to exhaust it maybe if the cupboard gets too warm. Might not be too big a deal to have the humidity high at this point but unless you want mouldy buds later try and sort this problem now. You could always bypass the timer with a twin power adapter like I do with my heat mat so it stays on at night when temps drop, just put it in before the timer and hook your fan directly to this, that way it runs 24/7. a double fan set up and timer for the lights off fan would be the best. Play around with it a bit and just keep measuring humidity and temps until you get it right, every enclosure is different, flows air different and holds humidity different.

Will help if I can but experimenting will usually give you the best results, you know your set up better than any one else =).

Great to see another cupboard grow. Good Luck and maybe someone else has some better advice =). Laters. GH72

 

 

Thanks GH - I'm not sure what you mean by a twin power adapter? can you show me a pic of what you mean? are you talking about a standard double adapter you connect to a powerpoint to attach two devices?

[The Hash Nibbler]

Thats the Shizz Morph, but not the dodgy old style adapters, a nice side by side adapter, cheap as shit mate from Bunnings.

Would show ya a Pic but mine is buried in the grow cupboard =) Hold on, just check my old pics. Nope sorry all deleted.

Would look like this / \ / \

Check the rating on it ' ' side by side outlets and one in. Want 10 amp Minimum. Hope this helps, Gh72

Edited June 7, 2010 by Grasshopper72

[jimbojones5678]

maybe just try running the fan 15mins on then 15 mins off - that usually takes care of the humidity and even if the lights off temp drops a bit then at least you won't be facing mold issues

 

Jimbo

[brick]

Does the shed have a wooden or concrete floor? If is just straight onto dirt that would increase the humidity as well. As you are pulling air up through the bottom of cabinet. In which case you would probably need a bloody big heater to help keep the humidity down.

 

What medium are you growing in?

Another source of humidity.

 

I live in Melb as well. I start my plants off around early August and veg them until October then put them outside. My cab is in the garage, not as severe as your shed probably. I have never had problems with humidity, I run the lights at night keeps reasonably warm. It can be more humid in the summer as you know.

I would be more worried about the roots getting too cold in the winter.

 

Maybe if you could raise the cabinet off the floor, go buy a good quality fan heater and have it blowing gentle heat directed at the bottom of the cabinet would. help.

[morphine34]

Hey folks,

 

Thought I'd pick your brains again! I was reading through posts in the growroom construction section and noticed several posts arguing that you should have your exhaust fans running all the time lest you get mould growing on your buds. I was intrigued at this as Grasshopper I remember you saying that you don't run exhaust fans at all in the night cycle (if I remember correctly?). If so, what sort of humidity readings do you get on your night cycle?

 

Mine is coming along nicely in that Im just testing the cabinet out at maintaining a nice environment for when plant/s go in. I will put up a pic once I've got it looking nice. Suffice to say, I have a thermometer controller on the power cord to the exhaust fan that is set for about 28-29 degrees celsius and takes about 15-20 seconds to vent the cabinet sufficiently (which I calculated to be only about a sq m) to reduce the temp. It does this in response to the rise in temp about every 4-5 minutes which seems pretty good to me. My earlier concerns re humidity appear literally to have evaporated as the 400 watt son t agro seems to bring it down to about 40% even a bit below at times.

 

Grasshopper I thought about your suggestion re running a blow heater near the intake vents to have warm air go into the cabinet. What I've done is taken a small column heater (one of those oil filled things) and placed it inside the cabinet and its able to maintain the temp at about the same temp as the light (remembe, my cab is in a garage in melbourne that is bloody cold at the moment ie 3 - 7 degrees ish). As there are no fans or expose heater elements Im thinking that this kind of heater is much safer than a blow heater but would be interested in anyones' thoughts as to that?

 

cheers,

 

Morphine

[morphine34]

Does the shed have a wooden or concrete floor? If is just straight onto dirt that would increase the humidity as well. As you are pulling air up through the bottom of cabinet. In which case you would probably need a bloody big heater to help keep the humidity down.

 

What medium are you growing in?

Another source of humidity.

 

I live in Melb as well. I start my plants off around early August and veg them until October then put them outside. My cab is in the garage, not as severe as your shed probably. I have never had problems with humidity, I run the lights at night keeps reasonably warm. It can be more humid in the summer as you know.

I would be more worried about the roots getting too cold in the winter.

 

Maybe if you could raise the cabinet off the floor, go buy a good quality fan heater and have it blowing gentle heat directed at the bottom of the cabinet would. help.

 

 

thanks for your help Brick50. Just wondering what temps you are running at with your cab when you grow? Do you get purple buds forming - reason I ask being that I read a few posts from people who said that a bit of cold is not too bad for the plants and that it turns the buds purple - dont know why thats important but hey what the hell!

 

Also, to answer your question, I have a concrete floor in the shed. I also have a heatmat now as Grasshopper suggested which I hope will help keep the roots warm.

 

cheers,

 

Morphine.

[Naycha]

Hey morphine, an oil heater would definitely be safer than a blower.

 

Just wondering though if you have checked the wattage on your heater? It's quite likely that the heater will be using way more power than your 400W light. The smallest blow heater I could find the other day was about the size of a shoebox and was 2000W.

[The Hash Nibbler]

hey Morphine, sorry mate been a bit busy lately working on the cupboard, seems like you got it all under control.

You could do an experiment, try no heater and just keep the heat mat on 24/7 and see what sort of night temps/humidity you are getting. My heat mat seems to be able to keep the grow area air warm over night, but I am indoors, so maybe it won't be warm enough in your shed? Would be a lot cheaper to run than the big oil cooler, but that is a good idea you came up with, and yes, always safer to run a sealed heater than an open blower type, I agree with Naycha there.

 

My Cupboard is 20c and 40% humidity at night, with no fan, but as they get a bit bigger I will put a small fan inside to blow air around the area at night. Happy Growing Mate, GH72