How to calculate dehumidifier size for grow room?

3 Key Takeaways:

🚀 A dehumidifier is necessary for a grow room because plants transpire heavily and contribute to moisture and humidity buildup, which can lead to problems.

🚀 To calculate the dehumidifier size for a grow room, you need to consider the number of plants, the square footage of the space, and the water input.

🚀 The number of pints of water or moisture that the dehumidifier can absorb from the air and grow room per day will determine its usefulness for your grow room.

Getting the right dehumidifier is crucial not just for homes, but also for grow rooms. Investing in the right size of dehumidifier will ensure the plants flourish, safe from the hazards of high humidity.

Let us look in detail at how to calculate the size of dehumidifier that a grow room requires and how it benefits a grow room. Let’s get started!

Is a dehumidifier necessary for a grow room?


It is easy to determine if you require a grow room dehumidifier; the simple answer is Yes! It is a fact that plants transpire heavily and a large amount of water and moisture that goes into play in a grow room or grow tent will contribute to moisture and humidity buildup, no matter how perfectly you have panned your grow room setup and drying mechanism.

Grow room’s dehumidification is a must. Just like air conditioners come in handy even when they do not seem essential, you will not regret the purchase of your grow room dehumidifier. Most often, growers find that a mini dehumidifier that is easily portable and has sufficient capacity to extra a good amount of water per day is sufficient.

The drying of air and environment that you get even from a mini dehumidifier might be just the dehumidification that your grow room needs to keep away too much moisture, bud rot, powdery mildew, mold, and other problems from your indoor garden.

A few things are absolutely essential to keep plants healthy. Apart from water, soil, manure, and air; an environment that has an adequate amount of humidity is also important. A high-quality dehumidifier (sometimes multiple dehumidifiers based on how much water is present in the grow room) is essential to provide the perfect temperature management.

How many pints of water or pint of moisture that the dehumidifier is able to absorb from the air and grow room per day will determine the usefulness of that unit for your grow room. Since, control over high humidity levels can be achieved only with a high capacity dehumidifier, investing in the purchase of the right unit is important.

How much moisture content gets accumulated in your grow tent will determine the right size dehumidifier that you will need. Each grow room’s specific needs would also be different. Based on the number of plants you have in the grow tent, you might even have to consider how many dehumidifiers you will actually need. Removing excess moisture across the tent is sometimes done with better efficiency with more than one dehumidifier.

Any indoor garden or grow room will benefit from the best dehumidifier for small spaces. Any specific environment that is exposed to a large amount of moisture is going to be faced with a shooting humidity level. That is the case with grow tents and grow rooms where the water input and output are high. Handling this high humidity level during daily operations is a key factor to keep the plants safe from pest problems.

The right size dehumidifier for grow rooms is pretty much calculated by the dehumidification needs of the space or grow room’s specific needs per day. For example, a small grow tent or small space with fewer square feet and a small number of plants will have minimal moisture to deal with. Large grow rooms with a complex setup and more plants will have to consider each plant type, gallons of water used, floor space and tent size, etc., before estimating the right size grow room dehumidifier required for moisture control.

To maximize the potential of the plants and the purpose of your indoor garden, it is a wise decision to purchase the right size of grow room dehumidifier and obtain seamless dehumidification for the space.

What kind of dehumidifier do I need for my grow room?

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Most new growers always wonder what kind of dehumidifiers should they look into for their indoor garden or grow rooms. A grow room dehumidifier purchase must be done carefully and it’s simple to identify what type of dehumidifier your grow room will need. Let us take a look into this further.

If your grow room is a very small space the moisture accumulation is also going to be less. A grow room’s dehumidifier should also be a type that is convenient for your routine. For example, rooms with air conditioners can sometimes manage with dehumidifiers that extract fewer pints of moisture. This is because an air conditioner is also able to absorb a certain amount of moisture. Hence, even the best dehumidifiers might be strong for a small square feet space.

Similarly, when it comes to grow tents or grow rooms you must first check how much water or how many pints of water you are faced with. For grow tents that need temperature management but have fewer pints of water input and fewer pints of moisture involved, the humidity levels may be easier to control.

An indoor garden like the above can use a mini dehumidifier. You must also remember, if the grow tent has many plants, you will have to check with a professional on how many dehumidifiers the grow room will need. The dehumidifier size also will depend on how much moisture the plants are exposed to. If there is too much moisture, on any particular day, the grow room’s specific needs or dehumidification needs are going to differ.

For a majority of the cases, residential dehumidifiers are equipped with the capacity to handle daily operations. Their water tank will also be sufficient, again based on how much water needs removing. Features like auto shut off will prevent overflows.

For example, if the main concern of your grow tent is pest problems or mold, a small desiccant dehumidifier with silica gel that requires a recharge alone should be a reliable choice. Although the gallons of water removed with a desiccant dehumidifier with minimal capacity is small, it is indeed a smart choice as a dehumidifier unit that is portable.

3. How many pint dehumidifier do I need for my grow room? [Grow Room Dehumidifier Size Calculation]

Before you purchase the best dehumidifier for a grow room, it is crucial to understand the figures involved in some basic information about your grow tent like how many gallons of water is present in the rooms per day. A simple math formula on grow room dehumidifier calculator will help us learn how to calculate dehumidifier size for grow room.

As discussed earlier, if the plants are growing in small spaces and the space has access to an air conditioner, you should note that before you step onto calculating the grow room’s dehumidification needs.

Be it a mini dehumidifier, one large high-quality dehumidifier, or multiple dehumidifiers- it is important to purchase the right dehumidifier size for your indoor garden to thoroughly handle high humidity levels and prevent too much moisture from accumulating in the floor, the grow tent setup, and the plant environment.

A proper estimation of every gallon of water used per day will help to avoid problems like powdery mildew and keep the plants healthy. The right size dehumidifiers not just protect every plant in the grow room, but also the space and air free from moisture.

Formula to calculate what size dehumidifier a grow room requires?

To calculate the dehumidifier size for the grow room or grow tent, first make a note of the number of plants you have, the square feet area of the space, and the water input; how much water or gallons of water is fed to the plants per day. This will let you know how much moisture you must expect to be removed from the space and air per day. This calculation works even for a small grow tent.

The formula is:

[number of plants] x [gallons per day per plant] x 8 [ gallon to pint factor]
= [recommended dehumidifier performance]

For better understanding, let us assume an example where you have 10 plants. For each plant, you spend 1 gallon per plant per day. Hence you have 10 gallons of moisture in the room.

As you know, dehumidifiers are rated in pints. By multiplying the number of gallons given to each plant each day by a factor f 8, will convert the gallons to pints. For this given example, the dehumidifier must have the capacity to remove 80 gallons of water per day.

If the plants are growing from the soil and they receive water only every alternate day, divide the total pints by 2 to get the average per day.

Investing in the right units is the key factor to maintaining the ideal humidity level in any space. Even the best dehumidifier might seem ineffective if the needs of the specific environment are not met. Silica gel dehumidifiers are also efficient to work for small spaces, to help not just with drying but to also free humidity to an extent.

What happens if humidity is too high during flowering?

A few things to bear in mind while having a grow room or indoor garden is that the requirement of the plant will change with seasons. This will have a direct impact on the pints of water sent back into the air and environment per day. It is important to be mindful of this fact, even in a very small grow tent.

For example, the high humidity level during flowering.

During the flowering season, water will evaporate through the leaves and stems to cool the plant. This natural process is going to contribute to a rise in the humidity level of the grow room. Keeping a track of flowering days or seasons will help to observe how much moisture is found in the air and to invest in dehumidifier units accordingly.

If the high humidity and pints of moisture in the air per day can be handled by a mini dehumidifier that is portable, you can go ahead with it. If the moisture levels are quite high and you need a dehumidifier that can absorb large pints of water per day, you can be assured to get excellent temperature management and moisture control with any high-quality dehumidifier. Large dehumidifiers and units are indeed a good pick during the flowering season.

High humidity when left unattended during flowering can cause heavy damage to the greenery in your indoor garden; also leading to mildew or powdery mildew and other diseases.

FAQ Section

1. What size dehumidifier do I need for 5×5 grow tent?

For a 5 x 5 grow tent, you can look into dehumidifiers that can remove 40 to 50 pints of water per day.

Make sure you thoroughly check how many pints of water the dehumidifier can extract per day before you pick them up; be it for small spaces or a large tent.

2. What Should My Humidity Be During Flowering?

As aforementioned, the amount of moisture in the grow room will increase naturally during flowering. This high humidity in any indoor garden can be controlled by calculating the pints of moisture to be absorbed before getting the dehumidifier size right.

The ideal humidity to be maintained during flowering is between 40% to 50% in grow rooms.

3. Where should a dehumidifier be placed in a grow tent?

Even the best dehumidifiers will seem futile when their placement is not correct. Every specific environment needs a different type of placement; the same rule applies to a grow room or grow tent.

Even if you have the best dehumidifier, how much moisture content is hanging around the grow tent, its square feet, the presence of an air conditioner, etc., are the factors that will decide the dehumidifier placement and the number of dehumidifiers you need.

Ideally, the most effective placement is at the center of the grow tent, above or next to the lights. The variables that affect the placement are; for example square feet footage of the room, dehumidifier size (mini dehumidifier or a large-sized one), airflow, how many pints of water the unit can absorb, water tank needs (if there is no provision for auto shut), etc.

You can always observe the placement for a month to notice performance. The water requirements of the tent might change every month, hence a portable unit is a better choice. If you have a unit that you can recharge, the same rules apply.

4. Will a dehumidifier dry out plants?

No! As long as the plants receive the right gallon of water they need correctly and the grow room setup is accurate, you need not worry about the dehumidifier drying the plants.

The dehumidifier unit nowadays is designed carefully to prevent drying.

5. How do you control humidity in a small grow room?

Here is how you can control humidity in a small grow room naturally:
> Use the right size dehumidifier unit
> Prevent water stagnation
> Seal and insulate the grow room area
> Improve air supply and airflow
> Ensure lighting and temperature is closely monitored

Wrapping Up

With this, we have reached the end f the article. Hope you are clear on how the grow room dehumidifier calculator works and how to get the right dehumidifier for a grow room. Share with us in the comments below which dehumidifiers you use for your grow tent and their usefulness in daily operations.


About The Author

Olivia — a self-confessed air quality addict — is a home climate enthusiast, fresh air advocate, and someone with deep personal experience and knowledge about mold extermination. Her work was mentioned in countless notable humidity publications. Previously she was an editor at Mold Remediation.