Ideal Grow Room Temperature with CO2 | Adding Rate + Temperature Ratio

Indoor gardening has become a trending hobby nowadays. Gardeners try to find new and innovative ways to grow plants indoors, which includes many out-of-season plants and crops. It needs great care and experience as you may destroy your plants with a single mistake.

Indoor gardeners are looking for ways to increase the production of plants. In fact, there is a simple way to get strong and healthy plants.

Do you know what is it?

It’s setting up a grow room with the addition of CO2. Now the question is what would be the ideal grow room temp with co2?

When you add high levels of CO2 in a grow room, the temperature should be between 85 degrees to 95 degrees. If you set levels at 1200 to 1500 PPM, maintain the temperature up to 95 degrees F. Remember that don’t set the temperature below 85 degrees as it may bring no benefit for your plants.

Normally, you want to make your grow room comfortable with the proper temperature. When you add CO2 at high levels, keep the temperature at 85 degrees. 

Keep an eye on maximum levels of carbon dioxide. Its level must be 1000 to 1500 PPM in your grow room. High levels may cause poisonous to plants, pets, and humans. So, avoid increasing CO2 levels.

Let’s dive into this post to know about the ideal temperature in detail!

What Is CO2

What do you know about CO2? It is important to have info about it as it plays an important role in grow room temperature maintenance. 

Basically, CO2 or carbon dioxide is what we discharge while breathing. Plants use it to start photosynthetic functions. Actually, plants breathe in CO2 during the daytime and give it out at night.

You can measure CO2 levels in PPM(parts per million). Typically, surrounding room levels are in the region of 300-400 ppm. You can see that at 390ppm level your plant’s growth should be similar to the growth in your garden outside.

If the CO2 level drops down from 200ppm, your plants stop growing. If you increase the CO2 level up to 1500ppm, your plant’s growth may also increase with it. As a grower, you can observe that at that level, the growth of your plants increases 100%.

How To Add CO2 To your Grow Room

Now the question is how do you set the CO2 level in your grow room? Don’t worry! I will tell you the easiest and natural way of adding CO2 to grow room. There are exhale CO2 bags for this purpose available at low prices in the market.

They fertilize carbon dioxide 24 hours a day so that you may not refill the bottles or use any expensive production units. CO2 bags work through photosynthesis (a process that helps leaves to make carbohydrates). THey change sunlight, carbon dioxide, and water into carbohydrates and oxygen by the work of chlorophyll in the chloroplast of the plant.

When plants maximize the process of photosynthesis, they become larger. The power is found in the mycelial part of the vented cultivator. This is a negative part of the fungus that cultivates carbon dioxide and it releases CO2 continually for 6 months. 

It is easy to check CO2 levels with a Mini CO2 Monitor that has a USB connection.

Note: As you know CO2 is heavier than air, you should hang the exhale CO2 bags at the top of the grow room. So, it may shower CO2 over your plants.

How do you use CO2 in grow room? Just watch this video to know well.

Common Temperature with CO2 in a Grow Room

Normally, you prepare your grow room according to the suitable temperature for the plants. But when you add too much CO2 it may be changed from the previous grow room temperature.

Before adding CO2, the temperature will be 85 degrees or below. But when you add CO2 in higher amounts then the temperature should be higher than 85 degrees. With CO2 you should maintain a temperature between 85 degrees F to 95 degrees F.

Many professional growers recommend keeping the temperature up to 95 degrees F. This temperature should be suitable if you maintain CO2 levels around 1200 to 1500 PPM.

If you keep the temperature below 85 degrees, you can’t see as many benefits of CO2 as you want. However, you can seal the grow room to save CO2 from escaping outside. It is easy to keep temp high when you are working on grow lights.

It doesn’t mean that you have to raise the temp of the grow room especially. CO2 helps you to protect the plants from light and heat stress.

Watch plants closely and if you find any sign of stress or heat, react accordingly!

Temperature Inside a Grow Room

You can check the temperature with Acurite Monitor which indicates low, ok, or high humidity.

Marijuana Temperature With CO2

What should you do if you are growing Marijuana indoors? How should you set up the temperature of the grow room?

Don’t Worry! It’s’ not as difficult as you think.

When CO2 increases from 0.12 to 0.15, the room temperature should be 85 degrees F that promotes the exchange of gases. In the case of high CO2 levels, photosynthesis, and chlorophyll production of plants can take the place at a high rate. So, the plants will be able to grow fast.

With high CO2 plants need more nutrients and water to get healthy growth. Don’t forget to check the water tank every day to a few days. It depends upon the size of the tank and be sure the tank may not be empty while watering the plants.

So, refill it with freshwater as well as nutrients.

Proper air circulation is also important for marijuana plants’ temperature. It will help in plant growth, humidity, and heat in the grow room.

It is best to set the grow room temperature around 60 to 65 degrees. By doing this, you will be able to keep your grow room warm at 75 degrees. Turn on grow lights and air conditioner that will keep Marijuana plants’ temperature cool.

best grow room temp with co2

Benefits of CO2 To Your Grow Room

Adding CO2 has a number of benefits for your grow tent. The most obvious benefit is that it brings a significant increase in the growth of the plant that will occur if your setup has been maximized. 

Additionally, if CO2 levels can be maintained around 1000-1200 ppm, you can set your grow room at a high temperature. It is crucial for the growers who are struggling to keep the temperature down and save the plants from the stress of high temperatures.

Now we discuss CO2 level during vegetation and flowering separately.

During Vegetation

At the stage of vegetative growth, add CO2 to increase the stretch rate of plants. It will allow your plants to have healthy and fast growth in a short period of time.

During Flowering

If you are planning to put CO2 at the flowering stage, be careful as it is the most important step. It is best to add CO2 to your grow room in the first two to three weeks of flowering. It will soon start flower production and increase flower size significantly.

Most Asking Questions

How Much Will CO2 Increase Yield?

There are a number of benefits to increase CO2 levels higher than the global average that is 1500 ppm. If you maintain CO2 at this level, yield can be increased by 30%.

Can Too Much CO2 Kill Plants?

Many plants need CO2 but excess use of it will be harmful. If you add too much carbon dioxide, plants can deteriorate and can produce fewer or small buds.

What Should be The Temperature of a Grow Room with CO2?

If CO2 is increased to 0.12-0.15, the grow room temperature should be 85 degrees F that promotes the exchange of gases.


Here is the end of our informative post about the best grow room temp with CO2. I have covered all the basic points related to the topic.

Hopefully, you will have to understand well the best temperature for grow room and adding the quantity of CO2 levels.

We have also mentioned the process of how do you add CO2 to grow the tent in detail. Surprisingly, you can set up your grow room temperature according to the needs of plants. With it, you may also decrease and increase the temperature accordingly.

Definitely, you have learned about the basic room temperature with carbon dioxide. If we missed any point, don,t hesitate to mention us in the comment section.

Lisa Marshall

Hi, This is Lisa Marshall. Lisa has been working with farmers for over thirteen years. It is his passion, hobby and profession. To facilitate other gardeners from her experience, she has decided to start this website to share her gardening experience with her plant lovers.

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