Do I really need a humidifier

[Christinac26]

Ok so I’m clueless on this. I have a 8 by 8 foot tent. I do have a outtake fan but do I also need a humidifier if so what kind? I live in Michigan and it’s prettty cold out also And is 74 degrees to cold for my plants ? I have 5 plants 4 are only 2 weeks old since taken tbat pic I have moved my little plants closer to the light

 

[Lime]

You didn't fill pots with soil?

 

[NorthernCosmos]

It depends on what the current temps an humidity are. 74°F (23.33°C) will work, but could perhaps be a couple of degrees higher. The ideal temperature and humidity are tied together by the Vapor Pressure Deficit (VPD) - there is a certain band of humidity/temperature combos that are optimal. You can learn more about it here:

Vapor Pressure Deficit & What It Means To You!

VPD - Overview Until the last couple years, Vapor Pressure Deficit, was measured mostly by research universities and agricultural laboratories. The tech available to growers these days has enabled us to dial a grow room in very accurately with regards to heat and RH. We all know that cannabis...

www.420magazine.com

VPD charts

Vapor Pressure Deficit (VPD) provides ideal temp/humidity pairs to maximize the health of your plants. In other words, if the temp goes up then humidity should also increase to maintain a better balance. Once you settle on one Vapor Pressure Deficit (VPD) chart (yah many to choose from), then...

www.420magazine.com

I don't measure the leaf temperatures and all that, but I use the charts to find the ballpark growing temp/humidity parameters, so that I know roughly how much humidification to use (or not!).

Seedlings like a bit of humidity all the way up to around 75%, but the flowering plants want less than 50%. In flower, high humidity carries the risk of bud mold/rot, so be careful there - not too humid and keep good air circulation.

As for the type of humidifier, the atomizing/misting ones are the most popular, but can also carry the risk of spreading minerals and microbes with the mist, depending on the water you use and the filtration capability of the humidifier. That can stick to surfaces, typically giving a white coating if you have much calcium in your water. Those same minerals and/or excessive water in the air can also clog your carbon filter - I've had this happen.

With evaporative humidifiers you don't run the risk of spreading stuff in the air or putting out too much humidity, and they often double as air cleaners. However, they'll not be able to raise the humidity as much as atomizing ones.

There's also the steam humidifiers. They're a bit like the atomizing ones in that they forcibly emit humidity into the air, but any microbes gets killed off during the boiling of the water. The steam is also warm, as opposed to atomizers which emit cold mist.

 

[Weaselcracker]

Hard to know. What’s your humidity now? I agree with maybe most of what NC posted above- but IMO you usually have a lot of wiggle room outside the ‘ideal’ labatory practices. .

Personally I would (and do) completely gnore the subject of VPD especially if just starting. Cannabis is versatile and grows all over the world in all sorts of conditions from desert to 100% RH jungle. .

My humidity in veg is very high- up to 90 and sometimes higher. No problems at all. Makes cloning very easy too.

Flowering I ran for years with RH in the high 70s and beyond. Mould tries to get you if the RH is high but there are tricks to cope. Now I have a dehumidifier which keeps it below 70 most of the time.

if your climate is very dry then for a small grow you can raise it with open water containers, etc.

 

[NorthernCosmos]

Personally I would (and do) completely gnore the subject of VPD especially if just starting. Cannabis is versatile and grows all over the world in all sorts of conditions from desert to 100% RH jungle. .

Yes, I agree. The VPD charts mostly tell me if I'm completely off. I'm not an advanced grower measuring leaf temperatures and so on... As an example, one day I might see the temps peak at, say, 28°C, and then it's good to have a reality check to guide me - in that case I'd know that the ideal would be to increase the humidity a bit.

I've lost enough buds to mold/rot that I'm a bit jittery about high humidity, but good air circulation helps there.

 

[Fuzzy Duck]

Don't let the science blind you for indoor growing where you might need an Oppressive Control Disorder (OCD) to control your grow room or tent

When mother nature is completely random at times high, low pressure dry periods with heat waves... How do the out door growers deal with these differences ?

Oh ye I forgot people have been growing out doors far longer than indoors & that appears to be a science these days ?


Some variables on RH for what conditions of grow & what you can get away with.


But if you have suffered with mold/rot a few times I would question you own grow conditions & ventilation methods.

 

[013]

Its not enough to monitor temp & rh on indoors grow - you need to be able to control it, but to start with get a hygrometer to see what the enviro readings are in your space. Even with a great light and stellar genetics, environment is right up there in the top 3

 

[NorthernCosmos]

But if you have suffered with mold/rot a few times I would question you own grow conditions & ventilation methods.

Oh, thanks... I guess...

Edit: Expanding on that: Yes, I always do. In a tent you can also get runaway, or seriously "out of band" conditions, by accident or noobness - I've experienced both in my short growing time. And I've learnt from it by monitoring and adjusting the growing conditions.

And yes, conditions can vary greatly and all that, but I reckon that taking an interest in and sharing details of our hobby is no "OCD" matter. In fact, precisely that seems to be a rather popular subject around here


Edit2: And to make this useful again, back on track, back to the OP!

Some posters think that it's too much to use charts and all, and I generally agree. I posted info about "VPD" for the chance to learn that there's something that says what the optimal temperature and humidity combination should be. The humidity doesn't necessarily need to be optimal to get good results though.

A couple of anecdotes from someone still learning to grow: In the winter the RH is down to 12% in the tent - I need to use a humidifier then. In my limited experience, seedlings grow better with a bit og humidity. On the other end of the spectrum of humidifier experiences, my atomizing humidifier once ran amok and clogged up my carbon filter so I got it "raining wet" in the tent with almost no circulation. Got some bud rot after that episode. If I didn't have a humidifier I'd still be able to grow, and might not have gotten that rot. YMMV.

So yeah, you may not need a humidifier at all, but your grow could possibly benefit, depending...

 

[nivek]

my flower room in my studio rarely gets over 35% rh, cept just after watering. and my plants are fine,, even good perhaps

i fot for years to get the humidity higher,, for not much really

rh is one part of the formula,, formulas can be adjusted to reach the same goal