Humidity during flowering - how low is too low?

[NorthEuropeanGuy]

Hello GWE, my girl (Northern Lights Auto) is mid way through flowering and I have been reading up on how to boost Trichome production. I have read that some growers take their humidity below 40%. I can only adjust my dehumidifier in steps of 5% so it's either 40% or 35%. Is 35% humidity too low? Thanks for all the great advice and stay healthy

[Farmall]

I have never gone below 35% but only by the fact, my ambient humidity is about 30% in winter months..during humid summers I get to 50% as a low and I am very pleased with that.. if you’re looking into trichome production, have you read up on using UV-B lamps? Running the dehumidifier probably costs more than running the bulb. And I can’t really find an answer as to why-a much lower humidity would increase trichs. 45-50 seems to be a generally accepted normal for flower stages.

[NorthEuropeanGuy]

Hi Farmall, thanks for that. I have read about UV-B for trichome boosting but as this is my first grow I am relutant to go too extreme. I think that I will stick to 40% RH and see how things pan out. I have just germinated my next seed and plan to try some LST and see how that impacts my yield

[Farmall]

NorthEuropeanGuy topping alone will make huge differences. Add some bondage and tie them down to add some nice spacing to the plant and try to make it grow as if it was going to support a glass tabletop. Wide and flat. By the way, the Uv-b works ... it tried using it 2 different grows... check out solacure.com

[SoOrbudgal]

I'm battling that myself low humidity but i'm early in flower.

[motheshmo]

I go down to 35 in the last couple weeks of flower- doesn't have a negative effect

[NorthEuropeanGuy]

Thanks motheshmo I'll give that a go next grow

[JDU]

My 1st grow I couldn't get the RH above 30 without turning the furnace off. The lowest overnight hydrometer reading was 11. I was running 3 humidifiers,1 in each tent & 1 in the room. My harvest was delicious. But I have nothing to compare it to as far as same strain grown same way but in better environment.

[NorthEuropeanGuy]

Thanks JDU, where I live we are lucky if the humidity ever gets below 70% From what I've read it seems that 35% to 40% is fine so I'll stick with that for this grow and try going lower on my next

[JDU]

I can't find it (I'm the king of that) but there was a thread not long ago that came to the general consensus that Rh got less & less important as a plant matured past seedling & especially clone stage.

[FunkyButtLovin]

Once I'm a couple weeks into flower I do not care what the RH is as long as it's not above 50-55%. I would prefer to keep it at around 40% but I'm not bothered enough to turn on a machine unless it gets around 55%, I have yet to use a humidifier for flowering plants, just give them a bit more water if it's drier & hotter than usual. As far as RH in flower is concerned my main and pretty much only priority is that I keep it low enough to prevent mold.

[gbauto]

The biggest issue running super low RH is that it creates a huge VPD at the leaf surface that makes nutrient/water uptake a challenge.

[Willyd]

I've tried playing with trichome production on my last mk ultra, i found dropping the temp about 10 degrees at night can help stimulate them, I noticed a change in a few days after dropping the temp. My humidity was also dropped to 30% in the last few weeks of flowering just to make sure there was no bud rot. I was only able to do that by closing the vent in my grow room and the fact I live in a very cold dry climate helps....for once

[SoOrbudgal]

mk ultra that's one fine quality smoke. I bought a dispensery preroll of it brother it was smooth.

[Willyd]

it turned out so nice I cured it for 3 weeks so smooth and full of flavor.