Power Mildew Humidity Spike Please Help

[kushdaking]

Anyone got any idea why my humidity spikes to 80% at night even with my exhaust system going all night? With lights on its 55%

This makes no sense to me so if someone could enlighten me that would be great.

Thank you

 

[rmoltis]

Anyone got any idea why my humidity spikes to 80% at night even with my exhaust system going all night? With lights on its 55%

This makes no sense to me so if someone could enlighten me that would be great.

Thank you

If your intake/exhaust draws outside air in as ventilation. That would explain it.

 

[kushdaking]

It's a sealed room it only exhaust air out of the room... now it could be causing a negative pressure which would force air through any cracks available but would that really cause humidity to 80%

 

[Mr Bee]

Plants do giv off alot of moistureduring lights out but your extractor should be taking care of it.

 

[SHIRDABZALOT]

It's because when your lights go out, the plants enter what is known as the respiration cycle. All the stomata (plants pores) open and let all the gases and humidity that it has stored all day. the plant does most of its healing and growing at night; much like the human body. The night cycle is when the dehumidifier does all its work. One way to combat this if you can't afford another dehuey is to place a heater in your room at night and it will displace humidity by raising your VPD as well as make your ac cycle on and will dehumidify further . I look for 50% humidity until week 6- 7 of flower then I drop it to 40 week 8 then 30 on the final week of flush on 10 week strains.

 

[kushdaking]

Plants do giv off alot of moistureduring lights out but your extractor should be taking care of it.

That's what I don't understand. I have a 2.5 ton mini split 4 1000w lights with 6 wall mount oscillating fans and a 8 inch max fan exhausting 24/7

 

[kushdaking]

It's because when your lights go out, the plants enter what is known as the respiration cycle. All the stomata (plants pores) open and let all the gases and humidity that it has stored all day. the plant does most of its healing and growing at night; much like the human body. The night cycle is when the dehumidifier does all its work. One way to combat this if you can't afford another dehuey is to place a heater in your room at night and it will displace humidity by raising your VPD as well as make your ac cycle on and will dehumidify further . I look for 50% humidity until week 6- 7 of flower then I drop it to 40 week 8 then 30 on the final week of flush on 10 week strains.

Do you recommend the heater or the dehuey

 

[Mr Bee]

Do you recommend the heater or the dehuey

A dey huey if u have one.a heater wont stop humidity but plants that have little fluctuation between the day temp & night temp-ie..its warm wen lights are off-iv noticed tighter nugs and slightly higher yeilds.compared with my grow room at night with the lights off.
Just my two bobs worth.

 

[GrowGod]

Dehumidifier will do both, heat the room and remove moisture.

 

[DemonTrich]

Mine kicked out 110* when cycling. F that crap!!!

 

[420bassmastr]

I've noticed the same problem, once lights turn on it runs the a.c. an pulls 20-30% humidity out. Lights go out and humidity starts to rise. Only way around it I'd say is the dehumidifier.
I'm running 3k over 12plants in a flood n drain system.

 

[GrowGod]

Mine kicked out 110* when cycling. F that crap!!!

What does that mean?

 

[rmoltis]

What does that mean?

It means the output air temperature of his dehumidifier in his room was °110.

 

[BudBogart]

It's a sealed room it only exhaust air out of the room... now it could be causing a negative pressure which would force air through any cracks available but would that really cause humidity to 80%

You have as much air leaking into the sealed room as you have blowing out the exhaust. Can't get around that, I don't think. Humidity always much higher at night, at least where I am.

 

[thunderfudge]

Heat suspends moisture in the air,cold makes it drop.keep the room heated during lights off and your exhaust will carry the moisture out of the room.as your temp changes at lights on and lights off,that is when these spikes occcur.a heater on 30 minutes before lights off continuously ran until 30 minutes after lights on will suspend all that moisture in the air and evacuate through your exhaust.the key is to never let your room temp sway more than 5-10°

 

[GrowGod]

It means the output air temperature of his dehumidifier in his room was °110.

Oh ok I see. But if your moving enough air shouldn't be a problem lights off. Lights on different story especially if your not air cooled like me.

 

[kushdaking]

OK so after doing a ton of research on dehueys.. because honestly I've never had this issue until I built a sealed room. It's telling me I need to remove as much water out of the air as I feed the plants per day... what's the truth to this??

 

[blazedahaze]

@kushdaking The problem your are having is because your lights will dry out the air during the on cycle and the plants will saturate the air at night via transpiration. You need to be able to control both humidification and de-humidification in your room. If you don't have a dehumidifier get one. If you don't have a humidifier/fogger get one. If you don't know about VPD, it's where it's at.. Temperature and humidity swings are your enemy, keeping a low temperature/humidity fluctuation makes a world of a difference.

 

[kushdaking]

@kushdaking The problem your are having is because your lights will dry out the air during the on cycle and the plants will saturate the air at night via transpiration. You need to be able to control both humidification and de-humidification in your room. If you don't have a dehumidifier get one. If you don't have a humidifier/fogger get one. If you don't know about VPD, it's where it's at.. Temperature and humidity swings are your enemy, keeping a low temperature/humidity fluctuation makes a world of a difference.

Vpd??? I've read forums on here about but no one spelled out the acronym

 

[blazedahaze]

@kushdaking Vapor Pressure Deficit, Try to keep your room between 78 and 82 degrees, 82 lights on, 78 lights off.. keep your humidity between 71-76 percent.. I start to drop the rh around week 4 to 50% and the temps also get lowered the last couple weeks. Search google for vpd chart to check out the temp/rh vpd relationship.