Cannabis is a resilient plant, that will grow, and survive under many conditions. To grow the best, top shelf cannabis, you have to give the plants the best environment possible. That can be done keeping your grow room at the right temperature and humidity for growing cannabis
Some strains of cannabis will thrive under high temperatures, whilst others will be stressed to the point where they will stop growing. Always read what your cannabis plant is telling you, and look out for signs of heat stress, or other problems caused by the environment.
Anything that can be said about growing cannabis is a guideline, as each plant can grow differently. In this article we will look at the ideal temperatures and humidity for growing cannabis. It will give you an idea of a good environment for your plants to grow.
If you have any questions about temperatures and humidity, then feel free to ask for help in our cannabis growers forum
Seedlings and Cuttings.
Seedlings, and cuttings will need a higher humidity than bigger plants. This is because the roots are not well established. The plant will absorb moisture out of the air, through the leaves. So keeping the humidity high during the germination and early cutting stage is ideal.
Use a dome, or a propagator over your young plants to lock in the moisture. Alternatively, you could raise the humidity of the whole grow room with a humidifier.
Temperature and Humidity for Vegging Cannabis Plants.
As your plants grow bigger during vegetation, and the root zone grows, your plant will draw less moisture from the air. Instead, you need to encourage your plant to evaporate more water from its leaves. The more the plant can evaporate ( sweat), the more it will drink. The more it drinks, the more it eats. Reduce humidity as the plant grows, and they will grow bigger, faster:
Controlling the Stretch of a Cannabis Plant
After you have flipped to flower, the next few weeks you will see a boom in growth. Your plant will go through the ” Stretch”. A cannabis plant can double, maybe even triple their size in the first 3 weeks of the flowering phase. This is called regenerative growth ( the stretch), and the plant does it to prepare for the formation of massive colas.
The stretch be controlled by using temperature. Keep lights off temperature less than five degrees celsius lower than lights on temperatures. Read our in depth guide on controlling the stretch.
The Ideal Temperature and Humidity for a Flowering Cannabis Plant.
As flowers form, you will have to reduce your humidity. If humidity is too high in your grow room, you are at risk of mould and rot on your buds!
Low humidity will encourage your plant to evaporate more water through its leaves. This will help your plant eat more food, and drink more water. Which in turn, will make her grow faster and bigger.
By lowering the temperature during the flowering cycle, you will put your plants under less stress. Less stress means the plant can spend more energy on productive growth.
Reducing the humidity during the last couple of weeks of the flowering cycle will make your plant grow more resins and crystals. To get humidity so low, you will need a good dehumidifier.
How to Monitor Temperature of Your Grow Room
A “Hygrometer” is the best way to see if your grow room is at the ideal temperature and humidity for growing cannabis. These devices will tell you the temperature, and the room humidity of the grow room.
You must have at least one of these in your grow room. By monitoring the temperature and humidity of your grow room, you will give your plant a perfect environment. Then they can just sit back, relax, and grow fine flowers.
Other Devices for measuring Temps and Humidity
With the rise in technology, there are many gadgets you can now purchase that will monitor your grow room for you! Some of the products, will automatically measure and adjust your grow rooms environment to the setting you select.
It is easier than ever to keep track of temperature and humidity. By offering your plant the perfect environment, you are on the way to growing perfect cannabis plants.
Thanks for reading! You can find more information on anything related to growing in our cannabis grow guides. All of our guides are written by experienced growers, and members of our cannabis growers forum. If you have any questions, sign up. It is free, and we are always happy to help!
16 thoughts on “Temperature and Humidity for Growing Cannabis.”
that would be very handy alright instead of having to check it all the time.
WIFI CONTROL shiz is getting fancy now lol 😆 seems kinda compilcatated lol, i’ll have to look itto em alright. just realised i said thongs in my last post lol.
Yep I run inkbird sensors and now have the mars 6 inch with humidity/temp controlled fans. I can set my humidifier to run at a set humidity level independent of the rest so it will work out what it needs and adjust accordingly. The wifi inkbird stuff is awesome though don’t know how I lived without it tbf.
thats pretty cheap alright, i have 1 extaactor fan and 1 blow fan that i put on sometimes and a heater i put in if it gets cold but thats it, no humidifier. all 3 are 45w max each so pretty cheap to run, the extractor is the only 1 going all the time and i have a speed controller on it too. plug in type and a temp 1 for the heater. havnt had any problems with em getting too hot or cold. be handy to have 1 unit to do all and controll automaticly alright, more thongs to consider 😀 👍
Inkbird-IHC-200, does humidity only. You can get a wi-fi one to. Turns on to humidifier to raise, and can turn on fan to lower.
Inkbird-ITC-308, does temp high so it will turn on a fan or small AC unit, and it will turn on low temp for like a heater. But these setting will be around the clock, no day/night. But high and low temp.
Inkbird-ITC-306, does day/night turns on heat only. No high temp setting, imo. I just use it for heat, day and night cycle.
All have wi-fi units. I would start with the combo packet. You get the humidity 200 and the temp controller 308. That is a must and will get you started. Hope this helps. 👍
@carraig Amazon that is £33, u can get the wifi version which is £45 not sure what tht be in usd tho So with this one its for heating temp, you can plug in your heater and fan but fan is very optional ideally want tht running constantly anyway, but if u have 2 fans, u can use that as a back up, which will turn on to cool down the tent if it ever gets too hot (most people just use the heating plug) relying on it to just turn it self off and turn on at the right times) There also one for the humidity need be careful tht it be compatible with your current humidifer
they control the fan and heater is it?
nice,, im sure my local shop has those, there was 1 other lad onto me before about something like these, said they are about 100 bucks, is that right? or maybe im thinking something different.
Clarify with someone else on this before u buy, but i think this is the right one for the day and night cycle
They take alot of weight of your shoulders knowing they set up, defo a must buy imo
i will thanks, ive got 2 of the plug in socket heat controler but they seem to register completly different temps too lol
8,,, as in EIGHT LOL
mad info on the testing them, thanks 👍 i’m a slow learner though 😆 🤣 hope ye have patience 😜
will have the google the inkbird ,thanks , shur 2 of ye cant be wrong lol, nice 1 👍 👍
@carraig If you do decide on getting one, you probably want to make sure it able to do different time schedules, so u can adjust temps for lights out periods as well, otherwise the basic one u be stuck on 1 setting, i wish i could tell u which one is which would need to clairfy
Cool, I’ll check em put 👍
Then you’ll get another one somehow, and they will read differently. So then you’ll get a third one to find out which one is correct, and then you’ll have three…. I’m the proud owner of like 8 of those bloody fucking things. I finally chose the Inkbird seeing as that’s what controls everything. But I keep all the other ones around to aggravate me daily. 🤣
If you ever want to check it, Place the meter in a zip lock with a bottle cap full of salt and a couple drops of water in it. Moist but not swimming. Zip it up, and wait 24hrs. It should read 75% RH. If it doesn’t then recalibrate the meter.
Welcome to Cannabis College. 🤣 Good luck man. 👍
@carraig Get yourself a inkbird if you havent already, help to control the climate alot
i’ll be coming back to these blogs over and over..
i only got my 1st humidity gauge last year and could not believe the fluctuations and the difference controlling it.