First grow - Humidity too high

[PIGUNIT]

Hey guys,

 

2x2x4 foot grow tent with 2xMars 300 led. Single negative pressure 4 inch 100cfm exhaust fan 

 

Temps are great 22-27c depending on time of day. Humidity is ok with no plants however as soon as I place my seedlings into the grow room humidity pushes into the high 80's low 90's.

 

According to BOM my area is 15c and 84 percent humidity right now at 8@night. 

 

My understanding is that I need to achieve 40 -70 humidity for veg and 40 - 50 for flower.

 

I don't consider a dehumidifier a realistic option because of the size of space. 

 

How can I beat this high humidity? The only thing I can think of is another 4 inch 100cfm intake fan. Any help at all appreciated.

 

Cheers

 

[afgahn bob]

Hey brother, dont know if this helps but i was looking at 70-80% RH in my room 4 a while

Went and got some cheap damp-rid from woolies that u hang up.

Got crystals in top that draw moisture ouy of air causing chemical reaction and filling bottom of bag with water

U be amazed at how much H20 takes out of air

Theirs another one like a bucket. Fill the top with crystals and empty water in toilet when it fills up

RH dropped from 70% to 35-40 in 3 days

Hope this helps

[micmac]

If you have high humidity you also need higher temps to keep plants in the green zone for optimal growth as long you have good exhaust and intake and plenty of air movement they will love it

[Gazza2001au]

When u run without a dehumidifier u are at the mercy of outdoors humidity so if its 85% outdoors thats the absolute best u can achieve

 

Is your tent 2x2 foot or 2x2 meters?

 

Its best to run a dehumidifier in a closed off grow room that way the dehumidifer will remove the moisture and maintain a set room humidity

 

Where as if your constantly venting your tent and running a dehumidifer your just drying air to be sucked out of the tent so it works out very innificent and u over work the dehumidifier

[PIGUNIT]

When u run without a dehumidifier u are at the mercy of outdoors humidity so if its 85% outdoors thats the absolute best u can achieve

 

Is your tent 2x2 foot or 2x2 meters?

 

Its best to run a dehumidifier in a closed off grow room that way the dehumidifer will remove the moisture and maintain a set room humidity

 

Where as if your constantly venting your tent and running a dehumidifer your just drying air to be sucked out of the tent so it works out very innificent and u over work the dehumidifier

 

2x2 foot so 0.6mx0.6m

[itchybromusic]

do a search on VPD Vapor Pressure Deficit , vegge green house growers live by good VPD

& a good VPD has a much higher humidity level that basically gets a plants plumbing working 

efficiently at a given temp 

 

looking at a VPD chart 22c = humidity between 60 - 70% , at 27c = humidity around 75%

 

these are numbers we have all been told are to high in flower & can cause mold but as more canna

growers use good environmental protocols with VPD the more they find it increases plant health & resistant's to many prob 

 

environment is mostly about being consistent , trying to avoid the peaks & troughs & trying to flatten out

that up & down line 

 

like buying split systems or Dehu's for a grow space , better to get a unit just big enough to do the job 

so the unit just stays on & doesn't click on & off by a thermostat causing peaks & troughs in temp & humidity

letting you keep a more even environment = happier plants 

[PIGUNIT]

The grow tent is inside a shed. I am bringing in air from outside the shed which is much cooler. If i brought in warmer air from inside the shed would that lessen my humidity problem?

[itchybromusic]

generally as temp go's up humidity go's down 

 

have you tried filtering your intake air , trapping some of the outdoor humidity in the filter 

 

i'm in a 2 car lined shed / man cave & have noticed a drop in humidity since adding filters to the intakes 

Edited August 29, 2017 by itchybromusic

[micmac]

generally as temp go's up humidity go's down

 

have you tried filtering your intake air , trapping some of the outdoor humidity in the filter

 

i'm in a 2 car lined shed / man cave & have noticed a drop in humidity since adding filters to the intakes

i have got to say if u can achieve constant VPD at the right levels your plants power since itchy showed this chart to me and keeping inside those guide lines at the moment my temp is 32c and humidity at 75% I can't believe there progress myself( actually I am blown away) Even at lower temps 17c I still get 60% humidity my plants have no signs of mould I think combine these conditions with good air intake plenty of air movement especially over plants and good exhaust system and u have perfect conditions, if you take a look at my new grow diary u will see what can happen in 18 days when u follow that VPD chart , took me a while to work out your environment is the key to getting real results

[Sir PsychoHashy]

The grow tent is inside a shed. I am bringing in air from outside the shed which is much cooler. If i brought in warmer air from inside the shed would that lessen my humidity problem?

 

Do not do that.