Humidity problem

[Mike80]

So do you think I should turn the heat back on?

Your temperature is too hot. According to the VPD chart if your temperature is at 27 C , your humidity needs to be 75%. Don’t use the heater. You need to drop your temperature. Look at this chart, you need to stay in the orange section.

 

[Rexer]

In a pinch you can also use some cheap moisture grabbers, I had to use some in order to drop my humidity (I bought the big ones for RVs). They don't last, but can buy you time to get it under better control.

 

[Woblaaaah]

Yea man keep the heater on unless it's getting to hot. You could hook it up to a thermostat so when it gets over 27*C in your tent it turns off automatically will keep the humidity down aswell

 

[Woblaaaah]

Don't need to be exact with the humidity between 35 and 70% is usually fine. Try keep day time temps at 27ish

 

[Canadadoes]

It's weird so when I had my heater on the humidity dropped to 48% so then I turned it off and now it has gone up to 65%

Which makes sense. If the moisture content of the air stays at the same level, and the temperature drops RH will increase. Which is why the moisture needs to be removed. Cold air doesn’t take as much water to be saturated in comparison to warm air.

 

[Matto835]

Yea man keep the heater on unless it's getting to hot. You could hook it up to a thermostat so when it gets over 27*C in your tent it turns off automatically will keep the humidity down aswell

Awsome thanks, ye I'm only a week or two from harvest so dont want anything to happen man

 

[Elvin]

If your basement is humid with the usual wet walls and seeping water you are fighting all that humidity.
Is there a duct on your furnace that you could block off from the furnace, then connect a duct from the intake on the tent and draw air from an upstairs room with it? I personally use about 15 feet of flexible duct to get conditioned air upstairs into my tents. Cheaper than cooling my entire hot upstairs.
Or is there someway else you could run some flexible ducting to the upstairs for your intake?
Your upstairs is likely a lot less humid than that wet basement and drawing air from somewhere other than the basement likely will help a lot.

 

[Weaselcracker]

I think you’re good. My RH has been higher than yours is now for most of the last ten years. Keep lots of airflow and a careful eye on the largest densest buds- google what to look for w early signs of mold.

 

[Calvados]

This shows the relationship between RH and temp and where you should be based on what stage of development your plant is at. The other thing to note is that RH goes up during lights out. Watering at the start of lights on will help. Regulating your temp at lights off will also help keep you in the right color. It doesn't have to be perfect. Your real concern is mold and powdery mildew. Make sure there is plenty of air movement and exchange. Make sure your plants aren't bunched together and that under the canopy any unnecessary foliage is removed.

A9BD79B8-0FAA-4B71-AF1F-5293872323FA.gif

• Calvados
• Jan 7, 2020

Vapor Pressure Deficit Chart

 

[Woblaaaah]

This shows the relationship between RH and temp and where you should be based on what stage of development your plant is at. The other thing to note is that RH goes up during lights out. Watering at the start of lights on will help. Regulating your temp at lights off will also help keep you in the right color. It doesn't have to be perfect. Your real concern is mold and powdery mildew. Make sure there is plenty of air movement and exchange. Make sure your plants aren't bunched together and that under the canopy any unnecessary foliage is removed.

A9BD79B8-0FAA-4B71-AF1F-5293872323FA.gif

• Calvados
• Jan 7, 2020

Vapor Pressure Deficit Chart

So a VPD of 1 is what your going for?

 

[Woblaaaah]

So a VPD of 1 is what your going for?

Or do you want low in veg to a higher vpd in late bloom?

 

[nickeluring]

I usually have a rH of 60% and over. I defoliate a lot and use many small fans inside the tent. If I don't, I get bud mold.

 

[Dbdub]

i think you'll be fine with those temps

 

[Dbdub]

I usually have a rH of 60% and over. I defoliate a lot and use many small fans inside the tent. If I don't, I get bud mold.

Do you find the end result the same as leaving the leaves ?

 

[Calvados]

So a VPD of 1 is what your going for?

Depends what stage. At the end of flower you want to be in the yellow.

 

[nickeluring]

Do you find the end result the same as leaving the leaves ?

I get much better yields since I started defoliating.

 

[Ghost Farmer]

Forget the heater you need a good humidifier and more positive air circulation which helps control humidity.

 

[Mountain Goat]

Hay ye sorry that's what I meant, I put the fan on full blast

I have same problem in my room (5m x 5m x 2.8m).......I have a 35 liter dehumidifier......good interior fan circulation and external in and extraction on full blast. I realized that the incoming and extraction is changing the entire rooms air in 6 minutes.......so my dehumidifier is really not having any effect as the air is really in and out.....I am really reliant on the RH of the incoming air.......and its cold and rainy. Net result is my room is cold and I have equivalent to external RH. If I slow in and out ventilation.......RH simply goes up........its a mission.......picked up downy mildew in my scrog.

 

[celticlyle]

I was getting 65 RH as well in my grow room when the plants were starting to get larger in size. I went the route of buying a small cheap $40 dehumidifier on ebay and it did almost nothing of note at all.
Unfortunately dehumidifiers are quite expensive tech especially when you want to reduce the RH by around 20%. I stay in a humid climate so I had to purchase a 10 liter dehumidifier that was around $150-200 and it does wonders. I have It placed outside the tent tho as the air that it sucks in and dehumidifies is blown back out at a few degrees higher, so it will also raise the room temp by a few degrees as well. Well worth the investment tho, saves those fat dank nugs ;D