Guys (and girls), do you have any recommendations re. dehumidifiers? I´m running two tents (4x4 - 9x5) inside a 9 x 10 room, and this last run I´ve suffered from some bud rot. Ambient humidity here is usually between 45%-55% and temps. about 68f (about 17c during the night, some 21-22c during the day).
personally i’d just grab the cheapest one off kijiji or craigslist - make sure it’s auto shutoff works so it doesn’t overflow on you and you should be good!
mine is 30 pints per day with a 1.5 gallon tank rated for 2000 sqf and worked great in a 6x10 room
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That is good news. I was thinking I might need a big unit, heavy and expensive to ship, and that gave me concerns about electrical capacity of my grow room circuit. Anyone else can chime in?
@legalcanada @Viva_Mexico . so something like this is way oversized? About how many daily pints would work? Daily water input should be about 80 pints (10 gallons between both tents, probably less).
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I agree with @legalcanada for that small of a area a standard dehumidifer from home depot etc should be fine. most of them have a hose connection above the tray to be able to hook up a 1/2 inch hose to drain constantly.
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good to know! thanks! @TropicalBiophile the stronger it is the less it will have to run = the less heat will be added or so my logic says. maybe it will generate the same heat.
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pints per day of evaporation is directly related to your growing style and stage of plants. at my current stage and conditions I am loosing around 50 gallons per day via transpiration and evaporation.
factors to think about.
day vs night time humidity
medium
plant size
day and night temps inside the area vs day and night time conditions outside the area.
-for small areas the outside factors is usually the main factor. ex, if you live in a rain forest, doesn’t much matter what you do, you will have higher humidity. sometimes you have to start out side the room and start to control it, than move to the grow space.
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Thanks brother! I didn´t know where else to post this, and felt like asking a quick question instead of clogging the pipes with a new thread.
Well… Humidiy here is quite constant (e.g. the bathroom whose shower I use to dry and cure is almost always at 50RH and about 68f/20c. I grow in soil, and humidity for vegging plants does not really concern me much and it rarely goes above 75% or so (a couple of nights a month it spikes to 88%!). I don´t care much about odor, so my inline fan and carbon filter have just been sitting there, once I hook them up it should help, by increasing the intake of 45-50% RH air from the rest of the place.
The problem is with my flowering tent, as it usually keeps around 50%, but at night when lights go off and I close the tent it just soars. 70, 75, 80%. It would be nice to keep it about 40% at least during lights off, to reduce the risk of botrytis (does it help with the quality/quantity as well?).
I enjoy training plants, and trying different techniques and mixes thereof with them, so my flowering girls are usually rather large, containers being between 5 - 10 gallons, and some with 30+ colas. I usually try to keep them growing horizontal so there is plenty of headroom.
Looking forward to what you have to say!
it’s always a good idea to use the search for a keyword to find a relevant thread before starting a new one, i could have also responded in the appropriate thread and tagged you to continue the discussion there i guess, i make so much work for these guys 
i’d say get a dehuey rated for at least double the sqf you need and you can set it to 45 so it will automatically kick on above that
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yes, that is a very common problem with high humidity when the lights go off. I will tell you what I do, and maybe it will give you an idea.
first of all because of the all the lighting and a/c’s my ambient grow room RH is around 35-39%. so, I added a 4 liter a hour humidifier to raise the RH. This raised the RH to around min 50% ( meter just stopped working). so, at my temps, 50% min is so so, not where I want to be, but good enough. problem is, when the lights go off, the humidity sky rockets. so, now, I have the humidifier on a timer that turns it off 45 min before the lights go off. At the same time, the exaust fan turns on pulling cooler and drier air from outside into the room replacing the day air, with fresh dry air for night time. By lowering my RH slightly before lights out, my RH remains more constant. condensation can be a problem if temps are to far apart. I also use serenade weekly for the first several weeks. you can also use it later but be careful as it leaves a slight smell for a couple of days. you can also use neem but the same applys.
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Thanks guys. I guess I will start by seeing where I am after hooking up the inline fan, but after that I´ll probably still need some form of dehuey. I´ve also thought about flipping the light schedule (lights off during the day, on at night) so as to keep a higher average temperature in the tent.
I do not really like to spray stuff on the plants… I don´t even do foliars. Probably I´ll get there, but in the meantime I´d rather try to keep buds as “clean” as possible.
So all this probably bring me back to step 1, which is choosing a dehuey. My room is about 700sq ft. (9x10x8h), so as per legal suggestion (twice the footage) and this guide I don´t need anything too big. 30 pints? It would be nice if someone has any comments re. brands or specific units, or if I just should grab the one I can find here.
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From your description of your conditions it sounds like you might not need a dehumidifier. Do you have any ventilation going (ideally venting to outside)? An exhaust fan might be enough. Or a small heater to keep the temp from dropping when the lights go off. Both options will probably use less electricity than a dehumidifier.
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Thanks brother. Yeah, I need to step up my ventilation. As I mentioned above, since smell is not a problem I haven´t even hooked up the fan and filter I got months ago, I probably will get to it this weekend. This will let me know where I actually stand re. humidity. For heat, I have thought about running the lights at night and have them off during the day.
Venting outside of the room is a bit more complicated though. The only way I see would be cutting a hole on one of the window glasses and hook it up there, probably with a vent cover. Is that the way people go about this?
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if you can remove the window you can get a piece of plywood and cut a whole in that, then put a drape or blind on the front of it to make it look like a closed window. the 2nd piece of wood in front is so the air isn’t obviously blowing the blinds. or you can use a fake AC exhaust window attachment thing
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great advice!! Air out the cab will help and get it on a humidistat dont want the fans running 24/7
Why not, my friend? Don´t you run your air scrubber 24/7?
you can set up a fan and filter inside the room that is constantly scrubbing the air and a 2nd exhaust fan and filter that operates on a thermostat or ozone generator for odor
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I have two fans one on a humidistat and one on a day night temp differential I have the opposite problem it’s bone dry here. I seal the tent up and supplement CO2.I guess i should have stayed out of this one my bad.
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