Lies our fathers told us humidity

[luvtogrow]

Keep that air moving.

 

[Newbienoob42]

I just started and I also run high humidity mostly because I have no room for a dehumidifier and the cheapy low power one doesn't do much. I run 86-89 degrees 69-75 r/h 1500-1700ppm during day at night I hit 76f 76 r/h. I have two tents (mother/veg and flower) connected with fans for co2 distribution between tents. I also use platinum leds (p650 and p150). I use 3.9 gal autopots with airdomes to help keep root zone temp down. So far I haven't had mold issues and buds feel like rocks on the autoflowers and pretty dense on the main strains on day 38 of flower. Other than the mk ultra I almost killed (don't use fox farm in auto pots only soil) everything looks pretty good I think. I use general hydroponics nutes in auto pots now the fox farm settles and has huge ph spikes.

 

[Newbienoob42]

Think the cheese auto is almost done the rest are around day 38

 

[Schkronis]

I bought used Aircare MA1201 for my 8x4 for just $40, Inkbird humidity controller is $25 on Amazon. I add eucalyptus, lavender and peppermint oils to the water at about 10 ml per gallon as a fungicide. 65% RH at 72-75F day Humi on and 50% RH 68-74F (humi off) during a night (day outside). At week 4 - turn off humidifier and turn on my Reptisun T5's for UV. I pull air from outside.

 

[dankninja]

good idea! I will try the oils next time it gets dry around here. most of the time I like to get my mothers comfy with slight changes in humidity and temp, just to toughen them up.

 

[KlipschGuy]

I like to let my humidity climb at night, 80% and around 40% and lower as harvest nears, during lights on. I've found that buds seem to get much denser almost spongy with this method.

 

[ROOBIX]

I have followed vpd exclusively this grow. Co2 is supplemented at 1500 ppm. Best results so far. Absolutely no pm or mold.
These are chunky dense tange buds that just finished wk 6.

 

[ROOBIX]

https://www.thcfarmer.com/community/threads/following-vpd-thru-flower.92190/

 

[Mickygreen]

Just my 2cent here but I always thought about humidity & temp as something to replicate in terms of the indigenous species of plant one intends to grow?

Hindu kush for instance ' is flowered in temp & humidity of 20c/24c & 25/50% humidity in the mountains so this is what I try to replicate.

From what I have read , each plant/strain will react slightly different depending on the strain.
I've had a ammo growing in 15% humidity from sprout to harvest and despite the low rh still yielded fat nugs of a decent size but lacked in terp profile

The same strain grown in the same setup with humidity in the 40% range had a lot more resin and flavour % yielded 15%more.

 

[Timtookalook]

The word around here is 65% early flowering... then reducing it at the middle and then down to about 50% in late flower. Just what most of the growers on here have stated they are doing. Also I would think CO2 would have some part to play with how high and how low you go as well.

And ofcouree, some strains prefer higher humidity then others, you have to do the research on your strain, or really pay attention day to day how your plants respond. I had ny exhaust fan on a time interval at one point, and the timer quit. My exhaust fan stayed off for quite a while.... humidity hit 75% as I had a humidifier going 24/7 cause its dry where im at. Temp never reached higher then 30°C... but the leaves were droopie and sad. I keep this paticular strain at 40 to 50% and there looking beautiful!... No Co2. 4th week of flowering.. 6 more to go.for this paticular strain they say (Caramelicious)

 

[Bloodfiregro]

I second this idea. I have two tents. One with a dehumidifier and one without. The one without seems to spike at night but the buds are bigger and denserthen the tent with a dehumidifier now after only a week of switching tents. They are different stains in each tent but I’ve notice humidity kicked the plants into gear.

And you gotta think that when people say they lower RH the last few weeks... you gotta remember that those last weeks are when the plants is done 99% of all growth or flowering and the flush is started, your about to harvest and dry so lower RH is needed. All I think low RH is for resin production and basically to begin the harvest “dryer” then if the RH was higher. Cuts down after harvest dry time also.

And as to bud Mold it’s probly because of bad air circulation while at higher RH. So I have at least three fans per tent plus a filter exhaust with a fan blowing it outside. I think as long as you don’t let the humidity sit and make it circulate then bud Mold will be less likely.

 

[Mickygreen]

I'm currently growing in a 2x4x6 tent with 2 blue og crossed grown from seed in a 70L oxypot xl
400w hps 2000k
150w full spec LED
12" oscillating fan
2 x 6" fans
5" carbon filter & 5" 280cm3 extractor
5L humidifier

My plants are beasts at 4ft tall and taking up every inch of the tent , I've had the humidity in the 60% / 70%for the past 4wks night & day with temp from 22c to 26c day & 18c / 24c night and I've seen no mold issues.

Actually , I've seen a increase in health & smell since RH% has increased during the wet season here.

Makes perfect sense to me that ' if tour room is well vented and continuously bringing in fresh air that's moving around the hole tent then all is well.

I place 6" fan at the bottom of my canopy inbetween my DWC and scrog net

Also place a 12" oscillating fan across my canopy & a 6" fan directed at my 400hps

I have noticed that my plants are eating more nutrients at higher humidity than at a lower one.....
7 days at R.TEMP 24c & RH 35% / 40% = 150ppm uptake
7 days at R.TEMP 24C & RH 55% / 70% = 300 ppm uptake

now! Will admit that plants will eat more at different times of the flowering cycle
But I'm sure if I dropped the humidity to 30% I would see them drinking more water than eating nutrients?

Wont a indica dom plant prefer a slightly drying condition than, let say a sativa from a wetter climate?
Hindu kush grown in the Hindu mountains grows in very dry conditions 20%/50% humidity with 30% being the average.

A pure sativa from Thailand flowering in september/October can experience temp's of 35c and humidity of 80%

 

[Timtookalook]

Hey, thanks for the reply! Nice looking buds ya got going there! I think your message kind of answered your own question.... I think each strain and/or breed make a difference on the plants pereference of humidity aswell as other factors... for example... if you prune your plants a sufficient amount (as i can see you do)... and all that air movemwnt throughout the plant, it can handle more humidity without a problem, and may be that paticular strains preference...high humidity... I am growing a indica/sativa hybrid 65/35 and found the plants look there best at 40% during its flowering stage... I have had some serious swings of humidity, since this is my first grow, and have made my adjustments according to my plants response... my room hit 70%.one day (had my exhaust fan on a timer that failed) and my girls were droopy and sad.... they bounced back with 12 hrs to there happy selves.... so I truly think humidity depends heavily on the strain,.and your trimming (some believe in no trimming ever! Right?) Thats my take.... happy growing... trade ounce for an ounce? Haha

 

[Trainedbat]

So I been growing for a long time and am starting to feel like i was lied to about humidity and cannabis especially during flowering. I have always tried to based on the litreature in books and online to keep the humidity in my flower room at 50- 55% day and night. However I am seriously beginning to suspect that actually cannabis likes much higher humidity when flowering like upwards of 70%. I have also followed some grow diaries on here by people that really seem to know what the fuck they are doing like gettogro and have seen that they are actually buying and installing large scale humidifiers in order to get the humidity in thier flower rooms up higher than what the litreature says. so what the fuck is the deal? I mean for real? why has all the litreature and online posts telling people to keep thier humidity down when that is really hurting the plants? So farmers tell me what u think and what you do and why you think and do what you do. Lets hear from some people that arent just vomiting back up jorge's books.

I think this has a lot more to do with the VPD, if the temp is higher you need higher humidity. There’s a chart I’ve been following with good success, I have the same thing going on which is why I came here looking for more info.

 

[tobh]

I think this has a lot more to do with the VPD, if the temp is higher you need higher humidity. There’s a chart I’ve been following with good success, I have the same thing going on which is why I came here looking for more info.

Not to be a dick, but did you bother looking at the last post date on this thread? It's a zombie thread now. Please don't do this. Let a dead thread lay dead.

If you have new antidotes to add, start a new thread referencing the old one. Raising an old thread like this is poor forum etiquette and muddies more current threads, which prevents us from continuing to build a solid knowledge base that's easy to search and of high quality.

And finally, welcome to the Farm. Out of all cannabis forums, this place has the deepest, most comprehensive depth of knowledge of just about any forum I've ever been on (decades on forums). Here's some reading material for you since you skipped the introduce yourself section:

So, you're new here, eh? Here's some stuff you may find handy...

So you're new here and you're not sure where to begin? Begin at the beginning. Our illustrious site administrator, logic, has put together some grow FAQs as well as a grower's dictionary for your education and enjoyment. Just follow the links and read, and most important of all... Enjoy...

www.thcfarmer.com

Your In Introductions, Now What...... All New Members Read!!!!

First off, HOWDY! And welcome to the farm! We are glad to make the acquaintance! Take a min and browse the forums so you get an understanding of the format we utilize here at the thcfarmer.. We have organized the forums so that it is easy for you to find the info you want. Utilizing the...

www.thcfarmer.com

Happy farming and good luck. @Aqua Man could you lock this thread so we can start to get a handle back on these kind of issues. It's becoming a real problem again.

 

[Kyleb]

if your day time temps are 70F what are you doing for night time temps? staying the same or going down to 65?


Are you running 70% humidity during the day and night? Or do you have different settings for day and night? I dont know but it seems like maybe its a good idea to run it slighlty drier during the dark period to help the plants respirate or something?

R you guys running the same during the day and night for humidity?

Thanks to all for the respones, I just find it incredible that all the books + magazines + most conventional regurgatated humidity threads online all the say the same shit about 50% humidity during the day and night which is cleary total fucking bullshit.

if you don't know what you don't know then why are you talking about it in the first place

 

[Kyleb]

if you don't know what you don't know then why are you talking about it in the first place

I'm saying what I'm saying is if anything you are giving out is information starts as like or maybe or this is what I do it is just an opinion and should be viewed that way just a bit of advice. But I love that everyone
is talking it out this is great

 

[Kyleb]

So I been growing for a long time and am starting to feel like i was lied to about humidity and cannabis especially during flowering. I have always tried to based on the litreature in books and online to keep the humidity in my flower room at 50- 55% day and night. However I am seriously beginning to suspect that actually cannabis likes much higher humidity when flowering like upwards of 70%. I have also followed some grow diaries on here by people that really seem to know what the fuck they are doing like gettogro and have seen that they are actually buying and installing large scale humidifiers in order to get the humidity in thier flower rooms up higher than what the litreature says. so what the fuck is the deal? I mean for real? why has all the litreature and online posts telling people to keep thier humidity down when that is really hurting the plants? So farmers tell me what u think and what you do and why you think and do what you do. Lets hear from some people that arent just vomiting back up jorge's books.

if we all grew no till and had a proper food web going on then we wouldn't need to worry about it at all because if we got fungus or if we got bugs or anything due to high humidity there would be elements in place to counteract that wouldn't that be great you know like how nature does it

 

[Kyleb]

if we all grew no till and had a proper food web going on then we wouldn't need to worry about it at all because if we got fungus or if we got bugs or anything due to high humidity there would be elements in place to counteract that wouldn't that be great you know like how nature does it

The soil food web I was referring to

 

[XxTheWolfxX]

This is another old thread but to revive it, unless your running co2, there would be no reason to have humidity levels at 70% to even 75% during flowering. The reason humidity levels are run higher with CO2 is because the temps run higher up to 95 degrees with LED. And to keep your VPD in a good range you have to run RH around 70-75%..

I run LED lights and the leaf surface temps runs .5 - 1.8 degrees Fahrenheit COOLER then ambient air temperature due to all the air movement needed to move the CO2 around the room and also to keep pests and mold in check. Because my leaf surface runs cooler then ambient air I run my flower rooms at 90-95 degrees with RH at 65-72% as my AC kicks on and cools it down to 90, my RH also decreases to about 65% when the AC kicks off and as the heat builds back up the RH also does with all the biomass... When the lights go out the room cools to 75 and my RH slides down to 55% with lights out. After week 6 co2 is down to 800ppm for week 7 and 600ppm for weeks 8 and 9. When I ramp down co2, I also lower temps..the last 3 weeks it’s 78 degrees lights on and 65 degrees lights off..the humidity only goes down as low as 50% I also run a hybrid setup that exhausts room air every 6 hours.

to grow with with both LED and CO2 really requires you to run hotter which in turn requires more humidity, to do it you need a sealed room and very good air movement both below canopy and above and all around. It’s high maintenance teetering on the razors edge. This type of operation isn’t your typical tent grow you have to have the equipment in place to DOMINATE your growing environment and have backup ventilation system in case something goes array.