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Cannabis temperature: know the ideal temperature for growth

So, you want to grow cannabis but aren’t too sure what the right temperature is for your weed plants to flourish.

Figuring out the ideal cannabis temperature for your particular strain is essential to a fruitful harvest. 

In this article, you’ll discover all you need to know about controlling the temperature and what to do if it gets too hot or cold.

Let’s begin!

Why is the temperature important to grow cannabis?

Unfortunately, unlike animals, plants cannot create their own heat. A cannabis plant’s ability to grow and to its fullest potential heavily depends on the skill and expertise of the grower. 

Temperature affects rates of cellular respiration, photosynthesis, and the prevalence of disease in cannabis—making it an essential aspect for the cultivator to control.

The effects of temperature on cannabis growth

The temperature for growing weed plays a significant role in cannabis growth. Let’s take a closer look.

Temperature and photosynthesis

Photosynthesis is positively affected by temperature until a certain point. Hotter than that, and the high temperatures begin to harm the plant. Lower temperatures, on the other hand, cause slower growth and a low yield. 

Temperature and respiration

A higher marijuana growing temperature significantly increases cellular respiration, where it becomes more than the rate of photosynthesis. When temperatures lower, respiration decreases, and so does the rate of growth. 

Temperature and disease

Like humans, cannabis plants are susceptible to disease—some diseases persevere better in warmer temps, while others in colder temperatures. 

Growers more commonly encounter gray mold in cold climates with moisture. Root rot is more likely in summer, and pathogens like powdery mildew grow in humid conditions.

Best temperature ranges to grow weed 

Manipulating the environment to the ideal temperature for growing weed is vital. Below you’ll find our best suggestions for the choice of temperature at the different stages of growth.

Clones and Seedlings  The perfect cannabis seedling temperature is between 68–77°F/20–25°C.
Vegetative stage This stage is best done between 68–77°F/20–25°C.
Flowering stage The best temperature for flowering cannabis is between 68–77°F/20–25C°.
Late flowering  Here you can lower the temperature a little bit to about 64–75°F/18–24C°.
Drying and curing  The best temperature and humidity for drying cannabis should be at about 70°F/21C°, and humidity at 50%.
Curing should happen at around the same temperature but between 58 and 65% humidity. 
Indica Indica strains do better in colder climates than other strains. Popular strains include Purple Kush, Northern Lights, and Blue Cheese.
Sativa  Sativa strains normally do better in warmer environments. Good strains include Durban Poison, Lemon Haze, and Strawberry Cough. 
Hybrid This depends on whether it’s indica or sativa-dominant. Indica-dominant strains do better in cold climates, while the reverse is true for sativa strains. 
Marijuana users enjoy hybrid strains such as Blue Dream, OG Kush, and Pineapple Express. 

What happens when the temperature is too hot? 

Figuring out the right growing weed temperature isn’t easy. The heat will restrict plant growth if it’s too warm, and the cannabis leaves will begin to curl.  

How do you fix the temperature?

There are several easy options to get the best temperature for weed. 

You can opt to move your grow lights away from your plants. Alternatively, you could increase circulation by using a fan.

For outdoor plants, you should water them both in the morning and the evening. You may also want to introduce artificial shade should the heat become an issue. 

Indoor marijuana grow tents are a great way to deal with temperature issues if you’re currently planting indoors.

What happens when the temperature is too cold? 

If the marijuana growing temperature is too low, this can stunt growth or even kill your cannabis plant. Getting a marijuana growing calendar is an excellent idea as it shows you the average temperature per month and other helpful information. 

How do you fix the temperature?

There are certain aspects out of your control. 

If you live in a colder climate, buying marijuana strains that grow well in cold environments may be better. Indica strains should be your go-to for this. 

Additionally, some plants do better indoors, so growing inside might be preferable to moderate temperature. Grow lights, heating mats, and space heaters are the privileges of the indoor cannabis grower. 

How can you control your growing room temperature?

Maintaining the ideal marijuana growing temp is paramount to having an excellent harvest.

Here are a few things that you can do to control the cannabis temperature:

  • Account for the wattage of your lightning. Higher wattage bulbs put off more heat and pose a risk to your cannabis. Stay on top of temperature monitoring in this case. 
  • Adjust your light schedule. Many growers keep their lights on all day. If you need to reduce the temperature, switch them off for a few hours a day. 
  • Add CO2 to the air. It’ll make it so that your plants can survive higher temperatures and induce faster growth.
  • Install some oscillating fans, which help with temperature and aid in preventing mold. 
  • Make sure that your growing room is sealed and insulated. 
  • If all else fails, try supplements. These can help make your plants become more resistant to warmth and recover better from heat. 

Unique concerns for outdoor growers

Indoor growing helps you evade the common issues found when growing cannabis outdoors. It’s much easier to get the best temperature to grow marijuana in a controlled setting.  

That said, you can try these solutions and suggestions if you prefer the idea of growing outdoors.

Greenhouses and cold frames

Getting a greenhouse will help you control the ideal temp and humidity for cannabis. The best choices for cannabis growth include polytunnel, lean-to, and freestanding greenhouses. 

If you’re looking for something a bit smaller, you can always opt for a cold frame. It protects your cannabis from cold weather while still getting heat from the sun. They’re cheaper than a greenhouse and suitable for small-scale outdoor growing. 

Patio heaters

Patio heaters are perfect for cold regions and will help keep your plants warm. You can also opt to use it only at night. 

Compost piles

Compost generates heat while it decomposes and so will naturally make the surroundings warmer. Placing compost piles near where your cannabis grows will aid by raising the temperature. 

Choose the right seeds

The optimum cannabis germination temperature is 78°F/25°C. That said, there are slight variations according to strain. The rule is that indica is better for cold temperatures, while sativa is better in warmer climates. 

Drying and curing

Drying and curing aids in making your buds not only smell better but become more potent as well. You need to ensure while drying cannabis buds you retain the temperature at about 68°F/20°C, and three days later, at about 61-64°F/16-18°C. 

Curing is best done slowly at low temperatures. Some connoisseurs even leave their buds to cure for up to a year!

FAQs related to cannabis temperature 

If you’re looking for simple answers to complex questions, read through our frequently asked questions. 

What temperature does cannabis grow best at?

Temperatures can vary, but for the most part, the best marijuana-growing temperatures are between 20–30°C/70–85°F during the daytime. At night the best temperature to grow weed is 25°C/75°F.

Can a negative temperature differential make the cannabis plant sick?

You can use a negative temperature differential to keep your plants stocky and short. However, it can harm certain strains, so you need to do research beforehand to determine whether it’s safe or not.

Can fluctuations in temperature stress cannabis?

Yes, it’s important to moderate the temperature as much as possible. A stressed plant will begin to get yellow leaves, and brown spots can begin to appear. 

Can indoor temperature swings damage cannabis?

Yes, it’s crucial to maintain consistent cannabis-growing temperatures. If the temperature is too high, it can degrade terpenes and stress the plant, resulting in damage. If the temperature is too low, it can damage nutrient uptake and negatively affect growth.

What is the best temperature for drying cannabis?

The best grow room temp, and humidity for drying cannabis is more or less 70°F/21C° with a humidity of 50%. 

What temperature will the buds on a marijuana plant stop growing?

At below 15°C/59°F, marijuana plants will struggle to grow and may end up dying. Cold temperatures slow the rate of photosynthesis. It helps to refer to a cannabis temperature chart if you’re unsure about a specific strain. 

What humidity should the marijuana grow room be?

The humidity for growing weed should be upwards of 70% at the initial stages, but you should reduce it to 40–50% as it reaches the flowering stage. It can go up to 60% during the vegetative stage. 

What is the lowest temperature cannabis can survive?

The lowest weed growing temperature depends on the strain. However, as a rule of thumb, anything below 50°F/10°C will cause a lot of strain on the plant. 

An important variable

As you can see, determining the optimum weed temperature plays an essential role in the growth and survival of cannabis plants. The fruitfulness and survival of your plants is all determined by the effective implementation of temperature control. 

At i49, we have the right seeds for you and your unique temperature concern. Check out our website to see what we offer.

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