Do I need a dehumidifier? (Illinois)

ImpulsiveGrower · Apr 22, 2021

I have a 2x8 grow space (closet) and I’m a new grower building out the space still. My plants are looking vigorous and healthy. It seems I always will need the humidifier but I’m wondering if I’ll need the dehumidifier. From what I’ve read some small home growers don’t need one and location play a factor. Without the humidifier it goes into the 30z so I’m wondering if I’ll mainly just need to humidify? I figure it will rise some when there’s more vegetation but not to dangerous levels. I have an ink bird that really comes handy at lights off since the levels do rise but it still kicks on the humidifier to keep it at optimal levels thru out the night. I also have an AC infinity exhausting the space and use a passive intake which brings air in from my bedroom. Thanx for any input!!
Strains:
•BLUE HASH
•BLUE OG
•PURPLE AYAHUASCA
•LSD
•AMNESIA HAZE
•GHOST TRAIN HAZE

Bluntsmoke · Apr 22, 2021

I use mine only in the winter when it's cool and raining outside. I'm in central california btw.

XxHammer · Apr 22, 2021

As long as your humidity is in the right range 40-60% then I wouldnt think you would have any use for a dehumidifier.

I am in Arizona, it is dry as hell, like without a humidifier running my humidity drops to like 5% or less. I am curious how Arizona and the low humidity will work when I get to drying/curing.

Have you updated your Grow Thread recently?

ImpulsiveGrower · Apr 22, 2021

XxHammer said:
As long as your humidity is in the right range 40-60% then I wouldnt think you would have any use for a dehumidifier.

I am in Arizona, it is dry as hell, like without a humidifier running my humidity drops to like 5% or less. I am curious how Arizona and the low humidity will work when I get to drying/curing.

Have you updated your Grow Thread recently?

Thanx for the input!! No I have not updated it yet but will be posting an update this weekend. The plants have been loving the kingbrite LED and really started to grow vigorously. I was a tad behind in size but things have really picked up since then I’m excited to share the progress with you guys. Transplanting to 5 gallon smart pots this weekend

XxHammer · Apr 22, 2021

Nice man! I will need to check out what these "Smart" Pots are.

Mine are really taking off as well. I just topped them the other day so I am waiting to see what effect that has.

Crazy how much I have learned already from this first grow. A lot more to learn.

Anthem · Apr 22, 2021

ImpulsiveGrower said:
I have a 2x8 grow space (closet) and I’m a new grower building out the space still. My plants are looking vigorous and healthy. It seems I always will need the humidifier but I’m wondering if I’ll need the dehumidifier. From what I’ve read some small home growers don’t need one and location play a factor. Without the humidifier it goes into the 30z so I’m wondering if I’ll mainly just need to humidify? I figure it will rise some when there’s more vegetation but not to dangerous levels. I have an ink bird that really comes handy at lights off since the levels do rise but it still kicks on the humidifier to keep it at optimal levels thru out the night. I also have an AC infinity exhausting the space and use a passive intake which brings air in from my bedroom. Thanx for any input!!
Strains:
•BLUE HASH
•BLUE OG
•PURPLE AYAHUASCA
•LSD
•AMNESIA HAZE
•GHOST TRAIN HAZE

Small plants do not give off much water vapor, (humidity) as the plants grow the water vapor the plant gives off will change. I would guess that with 6 plants in that space the humidity will rise to well over 60 percent. Some of it will depend on the following. How many air changes per minute, the humidity level of the air coming into the closer and lastly the overall size and density of the plants. I find that while my plants are small they need a humidifier because I see humidity levels in the mid 20's early in veg and by the time I am ready to flip to flower I am just running a dehumidifier.
The biggest challenge with not running a dehumidifier will come at the end of the 12/12 light period mid to late flower. The humidity will spike when lights go out. If the humidity gets too high late in flower you can get bud rot or WPM

ImpulsiveGrower · Apr 22, 2021

XxHammer said:
Nice man! I will need to check out what these "Smart" Pots are.

Mine are really taking off as well. I just topped them the other day so I am waiting to see what effect that has.

Crazy how much I have learned already from this first grow. A lot more to learn.

They are fabric pots which allow more airflow to the roots from all sides since it’s so breathable. It’s also a lot harder to overwater which is a nice benefit since I’m new to indoor growing. Ya I hope to be topping by early next week when I have 5-6 nodes...

ImpulsiveGrower · Apr 22, 2021

Anthem said:
Small plants do not give off much water vapor, (humidity) as the plants grow the water vapor the plant gives off will change. I would guess that with 6 plants in that space the humidity will rise to well over 60 percent. Some of it will depend on the following. How many air changes per minute, the humidity level of the air coming into the closer and lastly the overall size and density of the plants. I find that while my plants are small they need a humidifier because I see humidity levels in the mid 20's early in veg and by the time I am ready to flip to flower I am just running a dehumidifier.
The biggest challenge with not running a dehumidifier will come at the end of the 12/12 light period mid to late flower. The humidity will spike when lights go out. If the humidity gets too high late in flower you can get bud rot or WPM

Well my bedroom is the lung room for my grow space so it’s always gonna be temperature controlled air that’s always in the comfortable range for growing. To my calculations my air is exchanged entirely in just over 2 mins on the 3rd speed setting. The air is pull in from the bottom and the sides(right at canopy level once mature. I sealed off everything down to about 3-4ft off the floor. I have 8 settings on my ac infinity so I can crank it to move more air if needed since I’m only on #3 fan speed. So I’m not pulling any air from outside it all comes from the air inside the house. The humidity is way lower inside all the time it seems. I feel winter I’ll be running the humidifier non stop to try to keep it humid enough.

Anthem · Apr 22, 2021

ImpulsiveGrower said:
Well my bedroom is the lung room for my grow space so it’s always gonna be temperature controlled air that’s always in the comfortable range for growing. To my calculations my air is exchanged entirely in just over 2 mins on the 3rd speed setting. The air is pull in from the bottom and the sides(right at canopy level once mature. I sealed off everything down to about 3-4ft off the floor. I have 8 settings on my ac infinity so I can crank it to move more air if needed since I’m only on #3 fan speed. So I’m not pulling any air from outside it all comes from the air inside the house. The humidity is way lower inside all the time it seems. I feel winter I’ll be running the humidifier non stop to try to keep it humid enough.

You will have to keep an eye on the first couple grows to watch for humidity spikes at lights out. If it stays below I would say about 55-58 percent at lights out you should be good to go. Pulling air from an Air Conditioned space is good because A/C's remove humidity from the air. Might be fine just not totally sure it will.

Madmax · Apr 23, 2021

Buying a dehumidifier saved my ass in flower..i only have a 5x5 room growing 5 plants. its a complete backflip from what you do in veg room...does your exhaust expell into roof cavity or outside

Aqua Man · Apr 23, 2021

Where are you venting the tent to? If it's outside you don't need one. If it's inside you will probably want one in the room it vents into.

You don't need the humidifier at night plants are not transpiring and while I understand your going by VPD it does not apply at night and ideally humidity would be 10% lower at night because of this. You can probably get around this by plugging a small extension cord or powerbar into the humidifier plug of the inkbird and then a timer into that and the humidifier into the timer so it only runs during lights on. I think a timer would block both plugs if directly into the inkbird but that's an option if you can.

Madmax · Apr 23, 2021

Thats what i was thinking if its venting back into the room humidity will go up unless theres an air conditioner close by

Madmax · Apr 23, 2021

I keep changing my posts

Madmax · Apr 23, 2021

Did i miss spmething on here earlier..i popped out to get some popcorn..

ImpulsiveGrower · Apr 23, 2021

Aqua Man said:
Where are you venting the tent to? If it's outside you don't need one. If it's inside you will probably want one in the room it vents into.

You don't need the humidifier at night plants are not transpiring and while I understand your going by VPD it does not apply at night and ideally humidity would be 10% lower at night because of this. You can probably get around this by plugging a small extension cord or powerbar into the humidifier plug of the inkbird and then a timer into that and the humidifier into the timer so it only runs during lights on. I think a timer would block both plugs if directly into the inkbird but that's an option if you can.

It’s venting into the attic... I’ve been doing a lot of research so idk how I missed this part about humidity is supposed to go down at night for the health of the plants? So instead of the 60-70 range I should be having it like 50-60 during night hours? I’ll have to reset the ink or every night before lights out I guess right?

ImpulsiveGrower · Apr 23, 2021

And wuts VPD? I should know this since I’ve been literally obsessed with learning everything I need to know about growing.

Aqua Man · Apr 23, 2021

I would suggest venting out of the soffit or roof. That humid air can cause mold and issues in an attic.

Aqua Man · Apr 23, 2021

VPD is just temperature and humidity (temp being the more important factor in terms of impact) to control transpiration of plants and should be set first then humidity to meet the needs of the temp. This is responsible for nutrient uptake, transport and temperature regulation of the plants through evaporation.

VPD (vapor pressure deficit)

Ok i was gonna sit down and write out a whole article but i have been lazy so instead instead I'm going to copy paste because im lazy. This is not my work so let start. You may find this very long but its worth the read. Some may want to skip ahead. I have added here and there to what i feel is...

www.thcfarmer.com

Madmax · Apr 23, 2021

This is where having a dehumidifier works..you just select a setting say 60% for early flower then later select 50% .you wont have to reset every nite then..mines going 24/7..it actually heats the room a little of the night and keeping humidity in check..kills 2 birds with one stone.

ImpulsiveGrower · Apr 23, 2021

Aqua Man said:
I would suggest venting out of the soffit or roof. That humid air can cause mold and issues in an attic.

Well I’ve always noticed in the summer it’s hot a balls up in the attic so I figured my little closet grow wouldn’t affect the attic that much since it seems humid already during the summer. My house is a ranch style home so the attic is not super tall but it’s roughly 30x60 ft. I’ll investigate that further and try to vent it out the roof somehow but I just didn’t think my closet grow would cause that much humidity in my particular attic. So what’s VPD mean? And still looking for the answer about night time Rh. It’s supposed to be like 10%lower at night? Without the humidifier kicking on during the night the air being pulled into the space is wayyyyy lower that 10 percent the RH of the air being pulled into the space is in the upper 30z (38-40) so I feel I still need my humidifier to kick on but instead of 60% I should set it for 50% at night?

Do I need a dehumidifier? (Illinois)

Do I need a dehumidifier? (Illinois)

ImpulsiveGrower

Bluntsmoke

XxHammer

ImpulsiveGrower

XxHammer

Anthem

ImpulsiveGrower

ImpulsiveGrower

Anthem

Madmax

Aqua Man

Madmax

Madmax

Madmax

ImpulsiveGrower

ImpulsiveGrower

Aqua Man

Aqua Man

VPD (vapor pressure deficit)

Madmax

ImpulsiveGrower

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