It can be difficult to ensure your cannabis plants are at the right temperature. It is, according to some, as much science as art. However, that doesn’t mean you won’t be able to figure it out. It’s just a matter of learning a few basics first, which we will show you in this article. We will explain why cannabis temperature is more than degrees and why it is more difficult when grown indoors. You will also learn how to identify temperature-related problems and adjust your grow room.

The temperature’s impact on plants

Although cannabis plants are almost self-sufficient, they struggle to maintain temperature. Plants can’t generate their own heat, even though they are vital for their health. A cannabis plant is dependent entirely on its environment, unlike animals and humans.

How does a cannabis plant heat up?

How does a cannabis plant heat up

The combination of temperature and external light influences the plant’s temperature. Although it’s not possible to determine a plant’s exact temperature with a thermometer or other means, it can be used as a measure of its health.

Although cannabis plants will not die instantly from too much heat, they can experience slower growth due to excessive heat. The flowering process can be slowed down by high temperatures outside (above 80°C). You must ensure that the outside temperature is controlled during flowering if you want to grow buds high in cannabinoids.

Too much heat can cause stress in plants.

When your plant is too hot, photosynthesis can be affected, enzyme activity decreases and less proteins are produced. Some proteins even break down. Your plant could die if this goes on for too long.

Here are some ways that temperature can affect the cannabis growing process.

Temperature and Photosynthesis

We all know how sugar is made in plants.

Photosynthesis is one way temperature can impact the health of your plants. Photosynthesis can be done at temperatures between 60°F (15°C), and 85°F (30°C). Your plant will still produce enough sugar regardless of temperature.

When your plant has to send sugars to certain places, temperature is a major factor. Below 68°F (20°C) sugar won’t move as well. Your plant will be affected if the sugars get stuck.

Also, ensure that the plant is sufficiently warm to function.

This isn’t a big problem if it happens to mature plants. The backed up sugars will disappear once the temperature has been lowered. This situation can stunt the growth of immature plants.

Temperature and Respiration

Temperature and Respiration

The temperature sensitive function of respiration is also important. As the temperature drops, respiration decreases. This is a good thing as it reduces the plant’s energy use. It can also be dangerous.

Here are the reasons why this is a problem.

A lower temperature can cause a heavier crop to develop. This causes total crop respiration to increase. When the temperature rises, the plant requires more energy to keep it alive.

This creates a bigger problem.

There is little energy left for growth due to the extra energy required.

Other problems can also be caused by heat. Your plant will suffer more from heat stress if it gets too hot.

  • Spider mites
  • Root rot
  • White powdery mold
  • Nutrient burn
  • Wilting
  • Increased stretching

These conditions are more likely if the weather is humid or there is higher water transpiration.

The perfect temperature for cannabis cultivation for all life cycles

Temperature changes will affect the response of your cannabis plant differently depending on its stage..You must ensure that your plants are at the right temperature for their stage of growth as a grower. Here are the ideal temperatures for each stage of your growing process.

Cannabis Clones and Seedlings

Cannabis Clones and Seedlings

Clones don’t yet have a root system, so they rely on transpiration to get their water. Clones require high levels of humidity to grow, even until their roots are fully formed. To create the ideal humidity level for clones, many growers use a humidity dome.

Clones should be kept at a temperature between 68 and77°F (20-25°C), with high humidity. These temperatures will allow them to quickly develop roots and become self-sufficient. For seedlings, these temperatures are the same.

Temperature in the vegetative stage of cannabis

Temperature in the vegetative stage of cannabis

Young plants need to be kept at a high humidity level (70% or higher) and temperature between 68-77°F (20-25°C). As the plant ages, it is acceptable to have a lower humidity. Outdoor plants can tolerate higher temperature fluctuations, but indoor plants are more affected to it.

The ideal temperature for cannabis in the vegetative stage of life is between 68 and77°F (20-25°C), with moderate humidity and also a slightly cooler temperatures during the darkest periods.

Cooler nights are ideal for encouraging growth. Don’t let temperatures drop below 59oF (15oC). When the plant matures it will be able to tolerate cooler temperatures at night and dry air.

Temperature in the flowering stage of cannabis

Temperature in the flowering stage of cannabis

After your plant has reached the flowering stage, you can keep it at room temperature with low humidity. A temperature of 82°F (28°C) is the ideal temperature, unless you add CO2 to your growing room. Lower temperatures promote potent, trichome-rich buds that can be smelt and enjoyed before they are burned.

Keep your buds below 82°F (28°C). Higher temperatures can cause terpenes and bud growth to slow down. You could literally burn your buds if you heat them too much during this period. This can cause the buds to lose their flavor and smell as they grow.

After week 6, or 7, be extra careful to make it comfortable for your plants. You risk burning them by high heat.

To maximize trichome production, keep it slightly cooler in the dark. As it optimizes plant processes, a temperature change can trigger an increase in terpene. It’s important not to make it too cold.

This is what we call the dew point. When the air is unable to hold more water vapor, it becomes dew.

Terpenes are more than just taste and smell. They can also affect the overall color of the plant, as well as the buds. Terpenes are responsible to the tomato’s red color and may also play a similar role in some cannabis strains. You can get interesting colors from your plants by using the right dark-period temperatures (e.g., blue, pink, and purple).

The strain of marijuana used to produce this phenomenon will determine the results. The majority of marijuana plants grow green buds. However, if you want to find out what your cannabis plant can do, keep it at night and cool it.

Temperature at drying and curing cannabis

Temperature at drying and curing cannabis

The harvesting stage is only one step towards high-quality buds. Even the best genetics will not guarantee high-quality marijuana. You must dry and cure your buds properly. How the marijuana has been dried and cured is perhaps half of what makes great marijuana.

Professionally dried and cured marijuana has a higher potency, is smoother to smoke and looks better. It will give you that’sticky-icky feeling’ that marijuana lovers love.

You want to get the best harvest results. Make sure you maintain the right temperature and humidity throughout the process. This will prevent mold growth and dryness, as well as making it easier to grow the best weed.

Temperatures should be kept at 64°F (18°C) and humidity at 45%. These values are incorrect. These pictures were taken right after harvesting so the temperature and humidity were still high.

Don’t blow directly onto your buds. Create an airflow pattern. They will dry too fast.

The perfect Environment for Cannabis

You need to care about the environment in which your plants are growing, whether you’re indoors or out. You should create an environment that allows your plants to thrive.

Environment for Outdoor Cannabis Plants

Environment for Outdoor Cannabis Plants

Outdoor gardening can be difficult because it is hard to keep your plants warm. Outdoor varieties can withstand temperatures as low 50°F (10°C) without much difficulty. However, 50 degrees is not a good temperature as it slows down tissue growth and reduces photosynthesis late in the day.

Tissue damage can occur if the temperature drops below 40°F (4°C).

There are many ways to keep your plants warm outside. Here are some ideas:

  • Gas patio heaters
  • Covering made of polyethylene

Both can keep your garden warm during cold nights. It also protects plants against other weather elements. To encourage plant growth, the temperature should be at least 60 degrees.

Environment for Indoor Cannabis Plants

Environment for Indoor Cannabis Plants

The indoor grower controls the temperature of the room. This leaves as much room as possible for failure. You just need to make sure that your grow space is at the right temperature.

The Problem is:

There are many factors that influence the ideal temperature of your grow room. It is important to consider the location of your grow room within the building. A basement grows room is much cooler than an attic with a flat roof.

Other than that, your room’s size, airflow, number of lights, and extraction rates are important. This is important to remember when you are building your grow space.

The ideal temperature for cuttings and seedlings when the light is on is between 68ºF to 77ºF (20ºC or 25ºC). As plants age, the temperature can increase to a maximum of 82.5ºF (28ºC).

The temperature should be between 59ºF to 72ºF (15ºC or 22ºC) when the lights are off. The temperature difference between day and night must not be too large. A maximum difference of 18ºF (10ºC) is another important rule. It cannot drop below 64ºF (18ºF) in the night when it is 82ºF (28ºC) during daytime.

Indoor marijuana grows best at temperatures between 68-77ºF (20-25ºC), and a minimum of 18ºF (10ºC), to 60ºF (15ºC), during the day. The CO2-enriched plants will yield more at slightly higher temperatures of just below 82ºF (28ºC).

The floor should be kept at 80ºF (27ºC) so that the roots can warm up and the leaves and stems can withstand colder temperatures. If you have only a few plants, a heating mat is a great option.

To maintain optimal temperatures in larger gardens, a recirculating hot-water heater may be required.

Humidity correlates with temperature

Humidity correlates with temperature

You must also consider humidity when you are growing plants in a grow area.

Here’s some information about humidity. The air plants inhale contains water vapor. There are many factors that can affect the amount of water vapour in the air. This is called the humidity.

Because the plants’ leaves evaporate water, humidity levels in grow rooms are often higher than normal. Marijuana plants only use 10% of the water they absorb to grow, and the rest is evaporated.

The air can hold only a limited amount. Condensation begins when this limit is reached. Condensation appears as tiny droplets of water on your plant or in your grow room.

Temperature can affect humidity. This affects the amount of water vapor that can be held in the air. Colder air can hold less water vapor than warm air.

How do you know if your body is getting too much moisture?

Here are the top tips from experts:

  • You can measure the relative humidity.
  • The relative humidity (RH) is a measurement of the amount of moisture in the air. A reading of 70% would indicate that there is more water vapor in the air. However, 70% at 77 degrees is not the same as 70% 68 degrees, because warmer air can retain greater moisture.
  • 2 lbs of air at a higher temperature could hold as much as.45-ounces water vapour. But, 2 lbs of 68-degree air contains only.32 ounces. If the air is allowed to cool, it can retain less water vapor and cause condensation.

This is what we call the dew point. When the air is unable to hold more water vapor, it becomes dew.

This important, because It allows you to set the perfect temperature in your grow room. The example shows that the dewpoint of 77°C with 70% RH is 66°. To prevent excess moisture, the temperature must be kept above 66°F.

This is what we call the dew point. When the air is unable to hold more water vapor, it becomes dew.


It allows you to set the perfect temperature in your grow room.

The example shows that the dewpoint of 77°C with 70% RH is 66°. To prevent excess moisture, the temperature must be kept above 66°F.

It is vital to maintain the proper humidity in your grow space as moisture levels can change frequently.

Temperature drops are normal in a properly ventilated room. Fans and other ventilation methods are used to remove heat from lamps and change the humidity levels. It is important to maintain the right humidity levels for your plants, even though it changes frequently.

Measuring the temperature

Measuring the temperature

It’s simple to measure the temperature outdoors. It’s not difficult to measure indoor temperature.

First, use a thermometer to measure the temperature of your cannabis grow room. You can buy both digital and analog thermometers for as little as a few dollars. I use a digital thermo/hygrometer, something like this one, to see the maximum and minimum temperatures.

You can also get one with a temperature sensor attached to a wire so that you can hang it outside of your grow room and see the temperature even when the lights are off.

Here are some ways to get a good reading on your temperature:

  • Always measure the temperature in shade.
  • Take measurements at different points in your growing space.
  • Multiple fans can provide good airflow. Although lamps emit radiant heat, they do not alter the air temperature.
  • It will always feel a little warmer under the lamp than in a shaded area.
  • Lamps don’t cause temperature changes, so make sure you have enough space between the lamp und the plant.

This is not a misinterpretation. Radiant heat can affect the leaf temperature. You don’t want the lamps too close to your plants, as this could lead to heat stress.

Ensure a suitable temperature

It can be difficult to maintain the right temperature for your plants. However, it is possible. You can manage the environment when you grow indoors. Outdoor gardening is less certain.

The photosynthesis of marijuana plants depends on the temperature. Low temperatures can reduce the evaporation. This creates a suction force that takes nutrients from the roots and makes them smaller.

Next is:

The growing medium retains nutrients that are not needed but don’t absorb them. They eventually dissolve in the root environment. The growing medium’s acidity reduces the root function, which causes the plant to absorb less water and nutrients.

Growth stops.

It is important to maintain the right temperatures for your plants’ health.

If the temperature falls below 60°F (15°C) during dark periods, the plants will grow slower and produce less. If you don’t know much about the normal output of your garden, this won’t be obvious.

Heat stress can also be a problem in grow rooms that use lamps. This is due to improper lighting placement. The leaves are not actually burning in this instance, but they are damaged.

This is rare for outdoor plants, as it refers to temperatures above 105 degrees. If you’re not careful, indoor plants can experience this problem.

The top leaves of your plant will show heat stress. They will turn yellow and curl inward. The plant is trying to keep itself cool by curling inward. It is possible to see this in action by placing a lamp too close at your plant. This is a common mistake that can quickly endanger your plant’s life.

Even though it may appear small, a slight problem can cause serious problems in another part of the plant. It is essential to ensure a healthy environment in your grow space.

Adjust the temperature to correct problems

Adjust the temperature to correct problems

It is not too late if you have already noticed problems with temperature in your plants. These are the three possible problems you might encounter in your grow room and how to fix them.

Prevent and correct Heat stress

Avoid heat stress to your plants by keeping the lamps at a higher level than your plants, and/or using a fan to remove some heat.

You can get something stronger by installing air-cooled lamps with reflectors. This will lower the heat around the light. Light-generated heat is actually reduced by water-cooled lights, which are more efficient than those that use water-cooled lamps.

The HPS lights should be kept at a distance of 3-4 inches from the tops. The acceptable distance for air-cooled lights is between 2 and 3 inches for 100 watts.

Water-cooled lamps allow for a distance of approximately 2 inches from the tops of the plants. Light movers allow you to move lights closer or further away, depending on your preference.

Prevent temperatures that are too low

While a few nights of cold temperatures will not cause significant damage to your crop, it could be a problem if it occurs throughout the entire flowering period. The room can be heated by an electric heater or CO2 generator.

The temperature is not usually increased when the lights are on. The lamps will do that. It is important to evenly distribute the air throughout your room so that it maintains the same temperature. For this purpose, use swivel fans and point them between the lamp and the plant.

Also, fresh air should be evenly distributed throughout the area to prevent any cold spots. Winter is when temperatures can drop below freezing.

It can get very cold in your grow space if the lights are not on. There are many things you can do in order to raise the temperature.

These are some options:

  • Simple space heater with thermostat. (Be aware, they use a lot of power.
  • Radiator with thermostat
  • A CO2 generator
  • The extractor fan, which provides fresh air, can be turned off when the lamps are off. You can do this with either a thermostat-equipped fan controller or a timer.

Prevent excessive temperatures

Prevent excessive temperatures

In a grow area, heat can often become a problem. The lamps generate a lot heat. Although fluorescent lighting isn’t a problem, HPS lamps can heat your room to dangerous temperatures of 122°F (50°C). This is deadly for your marijuana plants.

How can you keep your plants from being burned?

The room’s dimensions are important. A 600-watt HPS lamp requires a minimum of 3 feet x 3 feet x 6.5 feet (100cmx100cmx200cm).

The following formula can be used to extract the data:

  • Extractor in cubic feet (meters) = number of watts divided with two
  • This formula requires an extractor fan with a volume of 22000 cubic feet (600m3). The extractor fan blows hot air outside, and then draws fresh air in.

However, that’s not all that you can do.

To prevent marijuana-smelling air from escaping, you can place a carbon filter onto your extractor. Ballasts, etc. are also possible. Ballasts can be placed outside of your grow room to generate heat.

The best way to lower the temperature is to turn your lights on at night. Your lamps will be on for several hours after the sun sets and then turn off after the sunrise. You’ll be able to turn on your lights at the coolest time of the day.

Imagine that you can also use your extractor to draw hot air into your growing room if it is hot outside. The room temperature will never drop below the outside temperature. Professional growers also use air conditioning units so that they can run it both during the day as well as at night.

One of the most important things to do to ensure a successful growth is to understand how to maintain the right temperature for your plants. It is easy to follow some best practices and measure often, then adjust as necessary. Even if you are growing outdoors, there are many ways to accomplish this.

If you place emphasis on the right temperature, your plants will thrive.

Our marijuana seed shop offers the best seeds to get your plants off to a great start. We ship to many countries including Australia, the United States and other countries. You can return the order if it doesn’t reach you, or the seeds don’t germinate.