Grow Tent

What Is The Ideal Temperature And Humidity For Your Grow Tent

Getting the best output as an indoor grower does not end with choosing the right strain(s) and substrate or materials to grow them on. While these are top requirements, the growth and yield of your plants considerably depend on other factors like lighting, water mechanisms, accessible nutrients, and, most importantly, the humidity and temperature of your grow tent.
This article highlights the importance of humidity and temperature in recording the optimal development and yield of strains. You will also learn what the optimal temperatures for each stage of the growth process are and practical tips to set them.
So, without wasting time, let’s get to it!

Why Are Temperature And Humidity Important For Plants?

As mentioned earlier, temperature and humidity remain two primary environmental factors influencing plants’ growth levels and overall health. Humidity is the amount of water vapor available in the air. When the amount of humidity in the air reduces, plant tissues lose water. In contrast, increased humidity facilitates the development of microbial and fungal pathogens.
In situations where the temperature is warmer, plants survive by closing their stomata, thereby reducing the amount of water they release. This helps them to cool off faster. However, closed stomata mean plants cannot move carbon dioxide and oxygen molecules through their cells, forcing them to suffocate on transpired gases and water vapors.
For plants, either too low or too high temperature or humidity levels in the grow tent will hinder their optimal growth and development.
Too High (Hot)Temps in the Grow Tent
Plants in grow tents with too hot temperatures (above 78°F) experience very slow growth. But that’s not all – these temperatures also make the plants vulnerable to other problems like root rot, nutrient burn, spider mites, white powdery mildew, wilting, and increased stretching.
Too Low (Cold) Temps in the Grow Tent
Similarly, plants in grow tents with colder temperatures (below 59°F) also experience slow growth. If it gets extremely cold, the plants may die from shock, grow with reduced yield, or get infested by mold.


What Are The Optimum Temperature And Humidity Levels For Each Growth Stage?

As you may already know, plant growth occurs in stages. All these stages are crucial to reaching a maximum yield at the end of the day, especially when growing indoors. The three main stages are the seedling stage, vegetative stage, and flowering stage.
Interestingly, each of these stages has its unique environment configurations. For example, your plants in the seedling stage require temperature and humidity levels that differ from the vegetative or flowering stage.
Here is a summary of the requirements of each stage;
1. Seedling Stage
This is the stage where the plant’s seedlings or clones develop roots. They need high humidity levels (between 75% and 85%) for this stage and temperatures between 74°F and 78°F.
2. Vegetative Stage
You should set your grow room temperature to between 70°F and 78°F once your plants move into the vegetative stage. Similarly, the relative humidity should be between 45% and 55%, ensuring the environment is neither too hot nor cold.
3. Flowering Stage
It is best to raise your temperature slightly higher at the flowering stage – between 75°F and 82°F. In contrast, the humidity levels should drop to between 35% and 45%. It could be as low as 30% in some cases.

temperature and HUmidity for different stage

Tips To Adjust Temperature and Humidity

Having highlighted each growth stage’s optimal temperature and humidity requirements, let’s look at how you can set them in your grow tent.
1. Track the current environmental conditions accurately. 
The first step is to assess the initial environmental conditions in your marijuana grow room.
You will need the following tools:
Thermometer: You need a digital or analog thermometer to measure the temperature in your marijuana grow room. It is advisable to use one with a temperature sensor that allows easy visibility of temperature readings.
Hygrometer: You can measure the relative humidity of your grow tent quickly and accurately using a hygrometer. The best models are digital hygrometers.
Inline Fan: An inline fan offers great temperature control in your grow room. It is designed to regularly replenish the volume of air in the grow tent, usually once every two or three minutes. SpiderFarmer offers one of the best inline fans for plant grow tents.
2. Lower the humidity and temperature levels. 
Based on your findings, you can lower the temperature and humidity levels in the grow tent to meet your requirements. The inline fan helps to control temperature and humidity, eliminate odor, and improve air quality and circulation. It is preferable to water the plants as soon as you turn on the light in the tent before the temp rises.
3. Increase the humidity and temperature levels. 
You can increase the humidity levels of your planting space by keeping the soil surface moist. In addition, you can have a wet towel or container containing water in a strategic place in the tent. The temperature will go up if you use more grow lights or add a space heater.

Spider Farmer Inline Fan


Plants grow best in an environment that is neither too dry nor too humid. It is easy to meet this condition if you are growing outdoors. Unfortunately, indoor growers do not have this luxury. They must create and maintain a growing environment that does not feel too hot or cold. Otherwise, the imbalances in humidity and temperature may cause some adverse effects in cannabis plants, including slow growth, reduced photosynthesis, pest and pathogen intrusion, nutrient burning, and root rot.
The tips offered above can help you set the right temp and humidity in your marijuana grow room for each growth stage of your plants and avoid these adverse effects.

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