DIY Dehumidifier CFM HELP!

[Traptito]

Hey guys,

I'm trying to get a new grow up and running but my humidity is out of control. I thought the split type would help but it only brings the RH down to around %64 at best.

I plan to have the plants in a 5x5 tent inside an air conditioned 9x9 room, If anything i'll probably just use the damn tent frame.

My question is would a 30 pint dehumidifier rated @ 106cfm work or should I go ahead and get a 50pint rated @ 206cfm? If I keep running exhaust out of the room it would be about 96cfm at %35 power. Fuck I hate thermodynamics. Could anyone chime in and help me out? Wouldn't running exhaust pretty much cancel out the dehumidifier? fml

 

[MickJ]

Hey guys,

I'm trying to get a new grow up and running but my humidity is out of control. I thought the split type would help but it only brings the RH down to around %64 at best.

I plan to have the plants in a 5x5 tent inside an air conditioned 9x9 room, f anything i'll probably just use the damn tent frame.

My question is would a 30 pint dehumidifier rated @ 106cfm work or should I go ahead and get a 50pint rated @ 206cfm? If I keep running exhaust out of the room it would be about 96cfm at %35 power. Fuck I hate thermodynamics. Could anyone chime in and help me out? wouldn't running exhaust pretty much cancel out the dehumidifier? fml

I would go with good circulation if the temperature is not too high and leave the humidity. Someone has a graph for ok temps with various humidity levels maybe @Dudeski ?

Sent from my comfy chair
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[Traptito]

I would go with good circulation if the temperature is not too high and leave the humidity. Someone has a graph for ok temps with various humidity levels maybe @Dudeski ?

Sent from my comfy chair
[emoji41][emoji2956][emoji848][emoji12][emoji42]

Thanks for your reply bro! Yeah I was hoping that was favorable as it would save me a ton in electricity not having a dehumy running 24/7. If it would work with an exhaust running I could get my vpd close to ideal though.. Just not sure it would be effective if the exhaust is constantly sucking the dry air out, know what I mean?

 

[Simplicio]

Hey guys,

I'm trying to get a new grow up and running but my humidity is out of control. I thought the split type would help but it only brings the RH down to around %64 at best.

I plan to have the plants in a 5x5 tent inside an air conditioned 9x9 room, If anything i'll probably just use the damn tent frame.

My question is would a 30 pint dehumidifier rated @ 106cfm work or should I go ahead and get a 50pint rated @ 206cfm? If I keep running exhaust out of the room it would be about 96cfm at %35 power. Fuck I hate thermodynamics. Could anyone chime in and help me out? Wouldn't running exhaust pretty much cancel out the dehumidifier? fml

I'd advise a humidifier, not a de-humidifier.
Cannabis loves high humidity.
My hydro plants thrive on RH in the upper 60s and lower 70s from seed to harvest without any of the rot or mold that we are warned to keep RH low to prevent.
Here's the VPD chart that academic research says will maximize growth for generic plants:

 

[Traptito]

I'd advise a humidifier, not a de-humidifier.
Cannabis loves high humidity.
My hydro plants thrive on RH in the upper 60s and lower 70s from seed to harvest without any of the rot or mold that we are warned to keep RH low to prevent.
Here's the VPD chart that academic research says will maximize growth for generic plants:

Thanks bro, see with that i'd be golden.. Throughout 24 hours ambient temps/humidity is 90F/75% high, 83F/69% low..

 

[Traptito]

This is the one i've been goin' off

 

[Banjacked]

@Simplicio this is what's been fucking with my head..

Why? If you ignore the VPD bit and all the numbers in boxes, then look at the coloured bits it becomes much clearer.

Seedling/early veg should ideally be in the "blue" range of higher humidity for temperature (why do you think some use humidomes or propagators?), late veg and into early flower you want the humidity to drop a little, then drop a bit further in late flower if you're keeping the temperature constant. In all cases, up to a certain point, you need higher humidity levels as temperature rises, lower humidity for lower temperatures. Outwith certain ranges, you don't do the plant any good, she's dead, Jim.

And the graph from @Simplicio is saying the same thing, but as a general guide over the more detailed version you have doing your head in, look at 25°C, as an example. On the "simple" chart that says "no higher than 60-65% RH" and on your chart that same 25°C kicks us in the 62.5% for "late veg/early flowering" stage of the plant, giving you a more general "rule of thumb" guide from @Simplicio over your more detailed, according to stage of growth and maturity, chart.

 

[Traptito]

Why? If you ignore the VPD bit and all the numbers in boxes, then look at the coloured bits it becomes much clearer.

Seedling/early veg should ideally be in the "blue" range of higher humidity for temperature (why do you think some use humidomes or propagators?), late veg and into early flower you want the humidity to drop a little, then drop a bit further in late flower if you're keeping the temperature constant. In all cases, up to a certain point, you need higher humidity levels as temperature rises, lower humidity for lower temperatures. Outwith certain ranges, you don't do the plant any good, she's dead, Jim.

And the graph from @Simplicio is saying the same thing, but as a general guide over the more detailed version you have doing your head in, look at 25°C, as an example. On the "simple" chart that says "no higher than 60-65% RH" and on your chart that same 25°C kicks us in the 62.5% for "late veg/early flowering" stage of the plant, giving you a more general "rule of thumb" guide from @Simplicio over your more detailed, according to stage of growth and maturity, chart.

I understand that, actually I worried myself more from reading articles citing general temp/humidity limits not realizing that if your temps are high, as long as your humidity is within range it's ok. My temps are higher but so is my humidity (being blue close to green/green) but not ever being even close to yellow.. Think that'd be a problem with late flower and potential pathogens?
Edit: Thanks for throwing in

 

[Banjacked]

I understand that, actually I worried myself more from reading articles citing general temp/humidity limits not realizing that if your temps are high, as long as your humidity is within range it's ok. My temps are higher but so is my humidity (being blue close to green/green) but not ever being even close to yellow.. Think that'd be a problem with late flower?

Personally, I doubt it, you're still within the "operating range", your chart is giving more detailed "ideal" levels but as long as you're not in or close to the red zones then the plant(s) should be happy enough.

What's more important is "how the plant(s) look" for if they look perky, happy, and are piling on the green bits then don't worry. If they look sad and depressed, then worry. They're hardy wee buggers, they can handle me, so if they look happy then why change anything now.

 

[Mañ'O'Green]

I have both a humidifier and a dehumidifier. I have a Pulse One sensor (whole thread here dedicated to it) that helps me keep in the green area of the more precise chart. Remember that that chart assumes a leaf temperature of 2°C less than the ambient air temperature. With my lights on the Leaf temperature is closer to 4°C lower than the air and there is another chart for that.

When I need to run the dehumidifier usually in late flower I have a 30 pint Frigidaire and it has to be emptied twice a day in a 10 x 11 room. I use the humidifier sometimes in early veg before the plants are big enough to respire enough water into the air.