Humidity....

[tmizzy]

Hi all, hows it goin? I am a new member to this wonderful place but have been observing from the shadows for months, i ve got a small grow on the go atm, just two beautiful ladies, one of which is Shiva shanti 1 from sensi seeds and cali orange bud, there growin strong and in the flushing phase thanks to all the advice i learnt on here but i had a quick question on humidity, reading up about it i found this quote:


"Experimentation has shown that a relative humidity of 65% to 80% increases growth rate. Below this level the plants develop extremely narrow and tissue paper thin leaves to try to prevent excess loss of water. Above 80% relative humidity the plant have trouble disposing of toxic chemicals through evaporation."



The humidity in my closet is too low, how can i get the level to increase? Peace

 

[stretchpuppy]

[edit: Strictly speaking about flowering.]

65-85% is nuts, IMO. You're inviting mold!

I'm normally around 50% in flower and just bought a dehumidifier to battle some problems I've been having late in flower and during the dry.

It's down around 35-40% now and I plan on keeping it that way.

I say you're safe... but how low is "too low" for you?

 

[Dan42nepa]

I think that may depend on the strain? My closet currently ranges between 40-50 and they seem fine. Very healthy left and stem growth.

 

[stretchpuppy]

Depends on strain and environment... I think I'm just in an area highly susceptible to mold and anything over 50% hurts.

 

[Guest]

I try to keep an RH of 70% with a cool mist humdifier in veg,you better believe they grow better at 70 than 50% RH.In flower its a no no though,I set my dehumidifier at 40% RH in the flower room

 

[tmizzy]

oh, ok thanks guys, im not saying its too low, tho on my cali lady the stems and leaves could be a healthier, and i was thinking that this might have been on of the factors but she was very sttressed in early life, rushed into it, germed the seeds an had 5 on the window and no lights when they sprouted so she spent awhile recieving very liuttle light! but still i am all the wiser now! Thanks!

 

[WiltedRoots]

if you do decide on raising the RH, IMO i think it would be wise to have proper air circulation if you dont already

 

[bigbear62]

So 71-75 temp &35-45 hum is good for flowering, 70-75 temp &70-80 hum for veg. boy due i have a problem!!! my temps 71-75,hum 33-39 day,66-69 temp,34-36hum at nite. so if want you fellas are saying ,if i put a humidifier in my room it will bring up humidity? due i need to put this on a timer to keep at about 70%??i was afaid to put 1 in thinking i mite get mold.my fresh air temp&hum is the same.should i put it in the other room??

 

[stretchpuppy]

The last thing I would do is put a Humidifier into my flower room. About 40% humidity sounds spot on... for my environment anyway.

 

[TGT]

I like higher humidity when in veg, but in flower 40% to 50% seems perfect. Anymore and you could get bud rot. But in veg I have noticed my plants have done much better with a little higher humidity. Just my input - good luck!

TGT

 

[Guest]

Besides the added growth benefit,a cool mist humidifier is a great natural mite repellent,its cut down my incidents of mites almost to nothing

 

[Guest]

Other than mold... everything that a plant produces that we look for as smokers
and growers, Resin, crystals, etc! Is the plant preserving the moisture in the buds! Thats why buds mold so easy. They have to be moist to grow seeds!
Added moiture is overkill! Unless you had something like 20% RH, then I would mabey do something.
The more lights, a lower RH and cooler temps= more crystally, resinous buds!
Veg cycle ofcourse is different.
Just remember if you get mold in your room...you got mold in your!


IMO, Willie!

 

[Guest]

I use a 45 pint dehumidifier in an 8 by 8 flower room and pull out a little over 2 gallons of water daily,its rweally unbelievable how much water is in the air when you have a room full of plants.

 

[Guest]

I use a 45 pint dehumidifier in an 8 by 8 flower room and pull out a little over 2 gallons of water daily,its rweally unbelievable how much water is in the air when you have a room full of plants.

Your right about that!

Willie!

 

[dyren]

Hey I've been having low humidity issues in my cab as well although I am unsure as to whether it has affected growth or not. All throughout veg my RH has been between 20 and 40 percent, more of the time closer to 20 though. I understand it should be a bit higher although I don't know how to raise it.

I'm growing in a small cab so a humidifier is out of the question. I tried leaving a tupperware container with water in there but it didn't help much. I only had about a cup of water in there though.

What do you guys suggest for this? I've heard of hanging damp rags in the box but I don't really want to resort to this. My air circulation is good.. perhaps too good??? The cab is APPROX. 2' x 2.5' x 5' and I've got one 20" plant and 2 12" plants (all bagseed). I made the flip to 12/12 just a few days ago... I hope as they flower the RH will go up (though hopefully not more than 40-50%, I don't want any mold!)

So my question is more for the next run. What can be done to raise RH?



Take care,
dyren



^ a little over a week in..



^ here she is 3 weeks later!! (on the right)

 

[stretchpuppy]

dyren if it aint broke dont fix it.

your veg plants look FINE at that humidity. why go adding more or something... when you look good as is?

 

[dyren]

I was just going by what I've heard... that higher humidity increases growth. I guess what I'm really trying to find out is if low humidity inhibits growth and by how much AND how low is too low.

I agree, if it ain't broke don't fix it, which is why I haven't been stressing over the issue. My babies are doing pretty good so far! I expect the humidity to increase as they bud up though and hopefully it won't surpass 40-50%.

Thanks for you input stretchpuppy!



Regards,
dyren

 

[stretchpuppy]

Those babies look great IMO, no yellowing, nice and green, whatever you're doing keep it up!

 

[h g]

i done a google search about humidity a while ago. I no longer have the info but..

At first the academic research i was came across was for maize grown in the Northern Hemisphere which indicated that a humidity for best crop production was 60%

then i refined the search to sativa's and i came across academic research done on indica and sativa rice plants. The experiments used low humidity at 60% and high humidity at 90%. The conclusion was that rice sativas grow best at 90% humidity and indica rice at 60%. I presume in asia ganja will grow wild next to rice in paddy fields.

i have no idea of the differences between rice and ganja. I know u can eat both but ive never tried smoking rice

i keep mine RH at 60% when flowering even for sativas. They might grow better at 90%RH but i aint taking the chance of getting mold. The dutch appear to be big on high humidity

 

[Suby]

It's a tossup IMHO, some sativas respond better to low RH and I find pure Indicas and Ind/Sat mixes like a little more RH.
I grow closet cab style and my RH seems to always be 20-30%, I've had little or no problems of any kind, a higher RH in veg seems to keep them from stretching too much and gets the leaves thicker and hardier.
I've tried everyhting in a cab but a cab is not a room and this is one of the limitations of a cab.
I'm pretty sure alot of desert grown weed gets little RH and do fine.

In flowering in a room situation i've tinkered around and find 50% is best as it keeps mold at bay but helps respiration and plants seem to balance out their nutrient vs. water needs a little better .

I like to use a fine mister and give them a plain foliar of RO or bottled water every chance I get, I do this just as the lights go out so as not to sun spot burn the plants.

Sub's