The cannabis temperature is an essential variable for all growers. It doesn’t matter whether you’re indoors or outdoors, or what stage your plant is at. There are specific temperatures that the plants need to be kept at to yield the amount of cannabis they’re supposed to.
If the temperature is too low or too high, this can cause a range of problems for your plants that can be hard to diagnose if you haven’t considered improper temperature as the cause. It can also mean you end up wasting your electricity, particularly if you’ve applied too much heat to indoor grow rooms.
That’s why we’ve written this comprehensive guide to cannabis growing temperature. We’ve divided it into a range of sections so that you can find what you need quickly and easily. Those sections include:
- The effects of temperature on cannabis
- The best temperature to grow cannabis
- Cannabis temperature control tips
- Measuring temperature
Once you’ve read it, you’ll know everything you need to get started with growing cannabis at the right temperatures.
The Effects Of Temperature On Cannabis
You’ll probably know that every plant needs heat to grow, and cannabis is no exception. It cannot create heat from within itself, so it needs to absorb the heat externally. If your plants are outdoors, then that will come from the sun. If they’re indoors, you’ll need to use lamps to replace the function of the sun.
Cannabis plants will stabilize their temperature by relying on light, heat, and evaporation. All of them need to be right, but there are specific consequences if the heat is too high or too low. Cannabis plants won’t die from overheating, but their growth will slow down drastically, which can delay your harvesting.
It can also make the buds less potent, which means your hard work won’t pay off as much as you thought it would. We’ll discuss the problems in more detail below, as well as giving some brief coverage of humidity.
An excess of heat will stress out your plants, and this has a range of internal chemical consequences. Photosynthesis will be less effective, enzymes in the plant will function less efficiently, and less protein will be created. At extreme levels of heat, proteins can break down.
High temperatures can also cause pests and diseases to damage your plants. Examples include:
- Nutrient burn
- Root rot
- Spider mites
There are also problems caused by lower temperatures. Photosynthesis will occur normally between 60-85 degrees Fahrenheit, but when the temperature is lower than 68 degrees, sugars in the plant will not transport well. This situation will resolve itself if the temperature is fixed within days, but in younger plants, growth speed will be reduced.
Plants also need to respire, and when the temperature isn’t high enough, then it will decrease. When this happens, the marijuana plant will become heavier to compensate. When temperatures go back up, it takes more energy to keep the plant alive and less energy is available for growth.
When plants respire, they release water vapor. The amount of this that’s in the air surrounding your plants can change depending on the environment. Indoors, it tends to be higher because of evaporation. Outdoors, it depends on the weather.
However, the air itself has a fixed amount of water vapor it can hold, and once that limit is surpassed, it will begin to condense and form droplets on your plants or in your grow room. This is important to note because when the air is hotter, it can contain more water vapor before it condenses.
You can measure the relative humidity to find out how much more water vapor the air can contain, and you can measure the dew point to find out at what temperature the vapor will condense. This information can then be used to determine the ideal temperature for cannabis in your grow room.
Best Temperature To Grow Cannabis
Finding the best cannabis temperature for growth will vary depending on where you’re growing it as well as the stage of growth that the plants are at. We’ve devoted a section to each part of the process so that you can find out the information that you need to know.
Another handy tool you can use is a cannabis temperature chart. These will give you a visual demonstration of the temperatures that you should have in your grow room. That way you don’t have to worry about any mathematical calculations.
However, even if you do have a chart, you still need to know how temperature affects your plants. That way, you’ll be able to understand why those temperatures are necessary and how to facilitate them.
The ideal temperature for cannabis may take a little experimentation because average temperature figures won’t take into account the size and set-up of your grow room if you’re growing indoors. So if any temperatures we discuss below don’t seem right for you, try a few degrees higher or lower.
When plants are yet to bud and flower, they will need humidity to be high and temperatures to be just above room temperature. Specific figures would be 70% or higher relative humidity, and temperatures of 68-77 degrees Fahrenheit.
As the plant ages, you can lower the humidity a little if you need to. This is usually done for indoor plants because their preferred temperature ranges are narrower compared to outdoor plants.
When your plants are in darkness, you’ll want to make a slight adjustment to the temperature and reduce it a little. That will encourage the plants to grow bigger and faster. But you’ll need to be careful. Temperatures shouldn’t drop any lower than 59 degrees.
As your plant gets older, it will be able to tolerate a cannabis growing temperature that’s lower during the day.
Once your plant has got through its vegetative stage, then the best part is about to begin. But to get it right, you’ll need to keep in mind that the temperature has to be different. You can’t keep things the same as they were.
Temperatures should be below 82 degrees Fahrenheit, and the humidity should be lower than it was during the vegetative stage. When you have lower temperatures, it encourages the buds to be high in trichomes, which gives them a stronger scent.
You’ll need to be careful not to let the temperature go above 82 degrees because it will encourage the evaporation of terpenes and slow down the growth of buds. You can also eliminate the smell and taste with excess heat. A cannabis temperature chart paired with a thermometer can help you with this.
Drying And Curing Stages
When you dry and cure your cannabis, it gives it a professional touch that people will notice. It also gives you a better smoking experience. But just like the growth stages, it requires certain temperatures to work effectively.
You should keep the temperature and humidity levels stable throughout the process so that the marijuana you get is the best quality possible, and no molding occurs. The specific numbers you’ll be looking for are different for drying and curing.
For drying, ensure the relative humidity is 45%, and the temperature is 64-70 degrees Fahrenheit. For curing in jars, keep the humidity at 58-65%, and the temperature the same as it would be for drying.
When you’re letting that cooler air move across your buds, don’t let it hit them directly, otherwise, they’ll dry out too fast.
Indoors vs. Outdoors
When you’re growing marijuana indoors, you’re in control of the conditions. Everything about your plants is down to you, and all you need to do is keep maintaining the right temperatures.
However, the temperature will vary depending on where your grow room is located. If it’s in a basement then it will be colder than an attic. Beyond that, the temperature will also be affected by the following variables:
- Light numbers
- Room size
- Extraction rates
When growing outdoors, you’ll find it more difficult to regulate temperature because the weather can change and your climate will affect the ranges those temperatures vary between.
As a general rule, most outdoor plants are hardier and will tolerate temperatures going as low as 50 degrees Fahrenheit, but 60 degrees and above is the ideal temperature for cannabis outdoors. You can use heaters and plastic covers to insulate and warm your plants when the weather is poor.
Cannabis Temperature Control Tips
We thought it would also be a helpful idea to include a range of tips that you can use to regulate your cannabis temperature. We came up with 7 of them, and we’ll list them out below.
- Use ventilation to push hot air out of your grow room
- Fans don’t cool down the air, they only move it
- Air-conditioning will reduce the temperatures
- The strain you use can affect how resistant it is to hot or cold temperatures
- The schedule of light you apply can be changed to help regulate temperatures
- You can order supplements to help your plants if they suffer from heat stress
If you’re in a warmer climate, a good heat-resistant strain you can buy is Sour Diesel. It can endure higher amounts of light and heat. Another strain that makes a good choice in warmer temperatures is Amnesia Haze.
Measuring Cannabis Temperature
Now that you know these tips, you might have wondered how to measure cannabis growing temperature. It’s much easier if you have a grow room. All you need to do is use a thermometer.
You can get ones that are digital or analog, but a digital one can give more accurate readings. One that has a memory function and serves as a hygrometer is the best. This means it measures humidity and records the highest and lowest temperatures recorded.
You can also use a sensor attached to a wire, with the thermometer hung outside your grow room. This allows you to measure the temperature when the lights are off. You should measure your temperature in several locations, and do it in the shade.
Another thing you should do is ensure there is good airflow when you measure your temperature so that the reading is more accurate.
Now that you’ve read the whole guide, you should be in an ideal position to know the best temperature to grow cannabis, why it’s important, the effects it can have on your plants, and how to find the right temperature for every stage of plant growth.
You should also keep in mind that the setup of your grow room, as well as the strains you choose, play a very important role in determining the ideal temperature for cannabis. This is why a cannabis temperature chart can come in so useful, as we discussed.
If you’d like to get a hold of heat-resistant strains, or any other varieties, then here’s what to do.