Best Temperature, Humidity for Weed - Expert Grower's Advice
Last Updated: Apr 10 2021
If you are an indoor cannabis grower, having the right knowledge about temperature for growing weed is all you need to worry about. Cannabis plants like temperatures similar to humans.
If you are not feeling comfortable with the temperature in your grow room, then it's probably too hot or too cold for your cannabis plant also. If you want high quality yield then marijuana temperature is something you need to take care.
If your grow room feels humid or dry, warm or cold, you may have to change and find the ideal temp and humidity for your grow tent.
Generally, temperature requirements for growing weed are as follows
This article will discuss why temperature for growing weed is essential and why it is more complicated when growing indoors. We will also discuss how to analyze temperature related problems and make adjustments in your grow room.
Stick to the article to learn everything about cannabis temperature, or you can directly jump to your favorite section.
Plants are independent in the case of making their food. But when it comes to temperature, plants are completely dependent on their environment.
Mainly, plants temperature depends on 3 factors -
A plant's temperature is a definite measure of its health.
Improper marijuana temperature can slow down the growth of cannabis. Additionally, it will cost a reduction in bud growth and decline in smell and potency.
If you are concerned about growing marijuana buds with lots of cannabinoids, you need to take care of the external temperature, especially during the flowering stage.
Maybe at this point, you are thinking, What happens to a plant if the temperature is too low or too high?
So let me break that down for you-
Cold temperatures lead to slow growth. Marijuana temperatures lower than 15C can upset plant growth, and freezing temperatures can even kill your plant.
In colder temperatures, cannabis plants are more sensitive to certain types of molds(especially when it's damp).
Cold temperatures and significant temperature fluctuation contribute to the over purpling of leaves and degrades the process of photosynthesis.
Photosynthesis is a complete process that involves a variety of small processes. Some of these processes are light-dependent, and some are light-independent.
The light-independent photosynthesis processes take place in stroma—fluid surrounding the grana (stacks of thylakoids) in chloroplasts. These plant reactions are catalyzed by specific enzymes and work best under certain ideal temperature conditions.
That's why it is said that weed plants growing in ideal temperatures will photosynthesize faster than plants grown in temperatures that are too high or low.
Fact - "A cannabis plant can survive in relatively cold temperature, but it can never provide best bud quality and aroma as compared to plants living in a good environment. Indoor plants are more sensitive to cold as compared to outdoor grown plants."
As per our research, a lot of people Google about What temperature does weed burn at?. Cannabis plants don't die or burn from the heat, but temperatures above the plant requirements may cause slower growth and poor quality buds.
Note: Temperature above 26C (in flowering stage) can slow down cannabis bud growth and make them airy and loose. The heat can also reduce the aroma of the developed buds.
In hot temperature, the Cannabis plant is more susceptible to many diseases like
Many growers struggle in this topic. There are many different ways to lower the temperature in a grow tent but you have to identify which method suits your marijuana plant better. Here we tried to list all the essential points that can help -
Serious note: Ac can work in any climate, but evaporative coolers work when humidity is less than 30%.
Maybe you are very serious about your cannabis growth. For that, you are harshly searching for the ideal marijuana temperature and humidity for your grow tent. But in your growing area, the temperature is very high. So, what to do in that case:-
It is crucial to pay serious attention to bud quality. Just because the plants are growing well, does not conclude that the bud quality will be optimum. So, you have to take care of both temperatures for growing weed and bud quality.
Cannabis prefers cool temperatures at night. Warm night temperature can slow down cannabis upward growth. But you can use this piece of knowledge to control plan growth. Growers who want to reduce the plant stretch or do not have more vertical spaces can artificially raise the marijuana temperature in the dark period to manipulate plant growth. Additionally, super cropping is also the best way to reduce plant height.
Super cropping is the second name for the HIGH-STRESS TRAINING technique. In this, you have to stress a plant by slightly hurting it in a planned way. It results in heavy plant bushes with more buds and high THC levels. It is the natural response of the plant to protect herself from the external environment.
We will discuss more about super cropping in our next dedicated article.
Here, we will discuss more about how the temperature for growing weed affects humidity.
Before we talk more about VPD, let's take a look at guidelines on ideal humidity requirements for growing cannabis.
These are basic guidelines but keep a note that plants can prosper at different relative humidities depending on the air temperature.
The air tends to form dew or water films over leaves when it becomes too saturated with water. It can lead to mildew or bud rot like problems with your cannabis plant. In high humidity, plants tend to grow very slowly.
Marijuana temperature and relative humidity for a grow tent is interconnected. You can fix a problem with one by fixing the other.
"Humidity": means the amount of water vapor that is held in the air. But " Relative Humidity" compares the maximum amount of water that air holds at a particular temperature.
I hope you are clear with this basic difference.
For instance, Warm air can "hold" more water as compared to cool air.
For some who are curious about the in-depth science behind this, VPD is the term used by greenhouse growers, which stands for "vapor pressure deficit," which roughly measures the grow room temperature and relative humidity.
"The best range for VPD in a greenhouse is from 0.45 kPa to 1.25 kPa, ideally sitting at around 0.85 kPa. As a general rule, most plants grow well at VPDs of between 0.8 to 0.95 kPa."
kPA stands for Kilopascal. Source - Wikipedia
While growing cannabis, taking account of relative humidity is as important as temperature for growing weed. As your cannabis bud quality directly depends on the ideal temp and humidity of the grow tent.
It becomes more crucial if you feel your grow room is dry or humid.
Pay more attention to bud quality. It is not necessary that the best VPD for water moving through plants is also suitable for bud growth, smell, and development. Additionally, each plant is different. So make sure to take care of bud quality before taking care of VPD numbers.
Ideal temp and humidity for grow tent- Comfortable room temperature around 20-30C and high humidity( 60-80%) is preferred for growing weed.
Clones do not have a root system. They need to get all the water via transpiration of the leaves(until the roots are formed).
That's the reason clones prefer a high humid environment. In many cases, people use a humidity dome or cloner to raise the grow room's humidity artificially. Please consider that you cannot raise humidity upto 80% because it will encourage severe problems to your cannabis like mold or mildew. It may also cause plants to root slower.
Clones root fastest in slightly warm temperatures about 20-30C- similar to a cannabis plant in a vegetative stage.
Ideal temp and humidity for the grow tent - Slightly warmer temperature of 20-30C and avoid very low humidity.
Young cannabis seedlings grow faster in mid humidity and warm temperatures.
Outdoor plants are robust to handle temperature fluctuations as compared to indoor cannabis plants.
In the vegetative stage, the temperature for growing weed needs to be around 20-30C. Moreover, try to give slightly colder grow room temperatures to weed plants during the dark period. It will promote the fastest and healthiest vegetative growing for your cannabis plant.
Cannabis plants in a vegetative stage like high grow room temperature when you enrich the grow room with supplements like CO2. There are few points for successful CO2 enrichment -
Ideal temp and humidity for grow tents- Avoid hot temperatures. Keep the temperature around(18-26C) and mid to low humidity.
It is recommended to keep the grow room temperature under 26C throughout the flowering stage, and it becomes more crucial in the second half when the buds are in the middle of development.
Keeping temperature low during the flowering stage helps produce potent, dense, smelly, and trichome covered buds.
Whereas hot temperatures during the flowering stage cause plant problems and slow bud growth. It also causes terpenes and potency to evaporate into the air.
Note 1: It is crucial to make sure buds are not exposed to extremely hot temperatures after the 6th or 7th week of the flowering stage. When terpene content in the buds starts developing, it also helps produce colored buds(if your cannabis has genes to produce buds).
Note 2: Slightly chill temperature is okay, but never expose your plants to freezing temperatures.
Starting with good genetics and taking proper care of your cannabis is the golden key top-notch quality buds. But your job is not over even after the cannabis harvest.
Around 50% of the final bud quality depends on how you choose to dry and cure cannabis buds.
Professionally cured buds are more potent, denser, smoother to smoke and look better.
Temperature and humidity for growing weed play a vital role while drying and curing the process of buds. If you follow the right procedure, you will end up with beautifully cured buds and not have to worry about mold or overdrying.
As we have mentioned, everything around the best temperature for growing optimum quality weed plants. This article will make you free from all the myths related to the ideal temperature and humidity required for a grow tent that you have applied till date to upgrade cannabis quality and growth.
Keep a note that the ideal temperature varies from one plant to another. Whenever you are working with a new plant (especially indoors), feel free to play around with the temperature settings and see how it affects your plant.
This personal experience will also reap a lot of knowledge about cannabis ideal temperature and humidity factors.
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