Noticed this evening at 32 days into flower my humidity over the last 24 hours was 25-32%.

There's nothing I can do to raise it, I've been through all the ways of raising it and none are practical.

What affect does low humidity have through a grow? Stunts growth? Reduces yield?

Is there a particular var that comes from or grows well in a dry environment?

hiya m8 as i see it being a novice at all this is that:-

if it is to humid 40-50 you will get MOLD or BUD ROT if not both!!!!

and it depends if they are INDICA or SATIVA
they (apparentley) are grown in different CLIMATES.......INDICA likes dry(desert) and not to much humidity

and SATIVA likes a bit of damp ie. (jungle) and overgrowth
are you in FLOWER or VEG?
coz different strain like a bit of a change when flowering( a bit dryer for most when in flower

CAMPERVANMAN

The guys 32 days into flower.

How come yer humdity is so low Would like to know how you got that with yer set up I would say yer Hygrometer is f&^&%d, yer using allmix and watering correct How about you water yer plants before they die

erm I would check that out I like my humidity between 40 - 50% So the MJ gods told me

between 40 and 50% in flower is bang on in my book.

Binary i may be teaching gramma to suck eggs but av you tried hanging a wet towel in there.Not dripping of course, or even folding a couple up and placing em here and there

its worked for me in the past.
low RH does affect growth and yield due to the plant slowly drying out.It needs the humidity to take moisture in through the leaves.It will spend alot of energy trying to do this and thus affecting growth.

Awesome !
Lower Humidity is BETTER when flowering it reduces the risk of the Dreaded budrot I wouldnt worry

yes maybe lower than in veg but not as low as 25-30.Not good at all

Try placing a shallow dish of water in your g/room under the lights or as owderb suggested... a damp towel
Hope this helps ya m8



dikki

Many thanks for the suggestions however in such a confined space I have no room for wet towels or bowls, should also add the temps have been fine, 22-26 deg.

Just accepting it's a problem I have to live with at the moment and for the next grow.

So it's indica strains that come from or grow better in a dry environment?

Binary you surely must be able to mist that's what I had to do to get the humidity up high enough when I used to breed reptiles , I used to have to mist 3 or 4 times a day so I just got one of those big pump up sprayer things you get from the garden center for spraying stuff on the garden , worked a treat .

Yes mate that wouldn't be a problem, however I've found loads of info on too high a humidity, but not much on too low a humidity.

Apart from a bit of curling at the leaf edges (Which I think it was RD or VRG mentioned this in a previous post) I can't see any other adverse effects as will be shown by the photos I'll post later.

They seem to be doing OK with an average of 25-30% throughout the grow, temps averaging 22-26 deg and ventilation running 24/7.

i've noticed over the past week or so that the ambient humidity has been low. if you're sucking in relatively dry air your plants have got more time to fill it with their own moisture so the growroom will be dryish too.
suits me fine, i've got flowers just starting to finish, as it were.

i keep a cheap humidity meter near the front door, saves alot of worry.

Hi Binary....I haven't been here long so forgive me if you know all/any of this already:

Low humidity will cause the plants to overtranspire (sweat too much, if you like!).
This results in the concentration of nutes in solution rising in the plant and nute burn occurs. This will affect the overall health of the plant and reduce yield. If you can't sort the RH out, drop the nute concentration (CF, EC, ppm) to counter the effect. Not sure actually....think you could be in dirt....if so, water more regularly and make the mix a little weaker next time if this is a persistent problem.

I aim for an RH of 40-45 throughout most of the plants life and 35-40 in the last few weeks (6 onwards) which is the important time to be checking for budrot and mold. Hanging wet towels is a great way to up the RH, you must be short of space if you can't manage this. I'd use a large flat tray (baking tray) filled with hydroton (expanded clay balls, available from your hydro shop) and water. The flat tray and the hydroton dramatically increase the surface area...put simply, this means that there is more space available for water molecules to "jump" into the air and increase the humidity. The same is true for a towel as opposed to, say, a tea towel as well as any other very porous, inert medium. I think you're growing in dirt so an idea might be to spread a layer of wet hydroton on the surface to provide a bit of humidity under each plant.

[EDIT] If you do mist, make sure it is only at lights off. The water droplets act like thousands of little magnifying glasses during the day and your plants will fry..ssssssss!
Anyway, I don't think this would help much as your problems are during the "day".

I think scotlander could be right though...If there's no room for wet towels, RH 25 at nearly 5 wks of flower in a crowded space is unlikely...your hygrometer could indeed be fu*ked or the batteries at least. Are the leaves dry or wilting? Are the leaftips burning?

Iv all ways had the humidity at 55% never over 60% in the mother and flower rooms, iv never had any problems with bud mould/ rot (never had problems with any kind of mould come to think of it) I think below 40% is a bit low, the stoma on the leaf is affected by the humidity, when the humidity is to high the stoma will close, when the humidity is low the stoma will open, I have found that the stoma are open fully at between 45and 60%(the stoma amongst other things is how the plant sweats), I also use co2 so if the stoma is fully open the plants are taking maximum dose or should I say the moor the better, at 35 days in to flower the plants are big enough to put lodes of humidity in to the grow room, if you are using big lamps or lodes of smaller lamps then the lamps are drying the humid air out to quickly, so it may be a good idea to get a humidifier to get the humidity up a bit…

What about introducing a bowl of boiling water next to your passive intakes at regular intervals, therefore drawing moisture in from the outside???


dikki

It would work, but a load of hassle, I have used heaters out of fish tanks before now, but you need to have the water temp higher than the room temp to have a good effect, the way I have my setup is, iv got a 40 pot set up, NFT, in the middle of the flower room raised 2 foot of the floor, at ether side I have 2 humidity f on all the time throughout the 12 h day(off at night), a heater low in the room and not on the floor, I also use co2,this is heaver than air so it drops to floor level, the inlets are at floor level and I have a 6 inch rvk on 24/7 blowing the mix back in to the canopy, so the conditions are constant and even I also use a room controller to monitor the heat and humidity..

I may get flogged for this but just my opinion. I have found that low humidity is a good thing, especially in flower. Low humidity can actually increase resin production. Many of us know that our special plant produces resin for defense amoung other things. Resin is also produced by the plant to keep the leaves from drying out ,thus a dryer climate should cause the plant to produce more. Just my experience in comparision grows. I have seen plants in 30% and below humidity produce slighly higher levels of trichomes as opposed to those in 45-50% humidity. Only draw back with lower humidity is you will have to water more often.

imo, it's the central heating.

i have had 50% rh in the veg room since i bought my hygrometer, just built me mini drobe in the loft, bit chilli in there so the mini drobe is surrounded by polystyrene.

i am currently just running some tests on it, atm there is 1 red enviro in there, no extraction / intake, but the hygro is showing 60% rh.

i expect this to drop when the air is being brought in from our bedroom.

i tried raising the rh when growing in the main drobe downstairs but bowls of water weren't helping, didn't try the towels, will keep that in mined, cheers owd.

good luck with it binary, i thought 50% was a bit dry , but if u ate'nt killed em yet with 25% i'm doing ok .

misting by hand would be easy, i looked seriously into growing shrooms a while ago, and the way to keep the aquarium (shroomgrobox) humid as a rainforest, was to use a sheet of perspex / glass and mist onto that so it can be caught and run off, which then also hydrates the air.

good luck with it m8, if you hang a damp towel near the intake then it should help oi reckons.

I've tried all the wet towel stuff, bowls, etc. and it's all a pain in the arse, going to live with it.

By the way, my intake is not from indoors.

IM having probs with low humidity... I got my setup in my garden shed as lot of you have probably heard me moaning about on another post.. and my girls are still alive but only just... A lot of this is due to low humidity on my opinion because before the humidity was between 50-60% in my other shed and now this shed is smaller and its seriously dry in there..

But just reading what cheifsmokingbud has said thats kinda reassuring... I msut say one of my girls has frosted up verry nicely indeed but the amount of bud its grown is next to nothing... maybe thats jsut because of the way the plants have been grown.. but i would agree that from what pics ive seen, the small bud i ahve on one of em is pretty frosty and it smells lush.. so maybe lower humidity (about 30-35%) isnt such a bad thing...

SJ

IM having probs with low humidity... I got my setup in my garden shed as lot of you have probably heard me moaning about on another post.. and my girls are still alive but only just... A lot of this is due to low humidity on my opinion because before the humidity was between 50-60% in my other shed and now this shed is smaller and its seriously dry in there..

But just reading what cheifsmokingbud has said thats kinda reassuring... I msut say one of my girls has frosted up verry nicely indeed but the amount of bud its grown is next to nothing... maybe thats jsut because of the way the plants have been grown.. but i would agree that from what pics ive seen, the small bud i ahve on one of em is pretty frosty and it smells lush.. so maybe lower humidity (about 30-35%) isnt such a bad thing...

SJ