What Size Dehumidifier for Grow Room?

Why Run A Dehumidifier In Grow Room?

So why can we just grow plants indoors without having to get a dehumidifier? I've covered its basic use and purpose, which is for you to control humidity in your grow area and to avoid too much moisture in your space.

If you're wondering how it does that, well it's simple. It basically pulls moisture from the air. The moisture it gets doesn't just disappear, of course.

Moisture gets stored in a pan or a container it comes with. So most likely, the bigger your humidifier is, the more storage for water it has.

Some humidifiers do not need containers. Think of inverters when it comes to air conditioning. A dehumidifier of that type only has a tubing or two that could lead to a collection vessel or drainage.

Some indoor growers even reuse the water they collected, which is smart because that could make them save more water.

Having enough humidity level in your grow area is required since this will keep your plants healthy.

If you try growing plants without trying to control your grow room's humidity, you'll most likely have plants with powdery mildew, a fungal disease.

Another thing that could happen is a bud rot. It's a type of mold that spreads and is only noticeable once it does. It usually hides and starts inside a bud.

The bottom line is, if you don't run a dehumidifier and not control your grow room's temperature, you'll get too much moisture. It would make your air stale and destroy your plants.

The Basics of Determining Dehumidifier Size for Grow Room

If you are familiar with the specs that grow room dehumidifiers come with, you might have noticed that they all have an 'moisture removal capacity (pints/day)' label with them. This is the key factor to consider when it's about determining the right dehumidifier for your grow room.

Let's start with the basics-

The Pints/24 Hours

Pints are units of moisture that are immersed in the air. When a dehumidifier is actively working, it can remove certain 'pints' of moisture at any given time. Usually, this calculation is conducted with a label of pints/24 hours.

So, if a dehumidifier comes with a label of 30 pints/24 hours, it shows the ability to take off 30 pints of air-borne moisture from the given area.

We can convert this unit of pints/24 hours into pound/24 hours as well. Just keep in mind that, one pint is equal to 1 pound of moisture.

The Physical Size

This is about the physical sizing of the dehumidifier that is taken into account. You see, there are grow room dehumidifiers that are more complex, heavier and take up more space. On the other hand, there are small grow room dehumidifier (mini dehumidifiers) that you can house with less space and size.

Even, there are micro-level dehumidifiers which don't induce any direct dehumidification, but passive dehumidification through absorbent material like silica gel, etc.

Usually, we refer to the first kind of models for grow rooms within 300 square feet of area. The second kind is, however, better for grow tents of up to 100 square feet area. In case you have a grow box, it's better to go with the micro-sized passive dehumidifiers.

Evaluating Your Grow Room's Dehumidification Needs

To properly size a dehumidifier for your indoor grow house, first consider the specific environment you'll be working in and the daily operations you'll be running. For example:

• How much water are you giving your plants every day?
• Are you running an air conditioner for temperature management? If so, what is its dehumidification rating? Check your particular setup; it should indicate how many pints of water it removes from the air per day.
• Are you using CO2 in your grow room?

Below are some key factors to keep in mind when determining the ideal size for your grow tent dehumidifier:

Gallons Per Day

To determine how much moisture buildup will occur in your grow room, work out a rough estimate of the number of plants in your space and how much water they'll receive. For example, 30 plants that receive 1 gallon of water per plant per day means a water input of 30 gallons.

Each gallon holds 8 pints, which would be a total of 240 pints of water per day. This is converted into pounds per hour; 1 pint is equal to approximately 1 pound of moisture. Therefore, in this example, 240 pints of water would equal 240 pounds of water per day. This means 10 pounds of moisture per hour is being removed over 24 hours.

Plants transpire roughly 97% of the water they're given, so pinpointing the amount of watering you plan to do is an easy way to approximate how much moisture will need to be removed each day.

Temperature Range

Different types of grow rooms and plants will require different temperature ranges to thrive, and different growing cycles will require different temperature ranges.

For instance, a cloning room may start out at 75 °F degrees, while a flowering room for the same plant may be held at 78-80 °F. And a drying and curing room may see temperatures closer to 65°F degrees.  

Things To Consider When Buying A Good Grow Tent Dehumidifier

Since humidity and temperatures coincide, it's best to get a dehumidifier that can efficiently function no matter what the temperature is.

Keep in mind that the cooler your place is, the more likely that your dehumidifier can't maximize its functionality.

The size of your dehumidifier does depend on the number of plants and the size of your grow room, but if you want to get a big-sized dehumidifier, that's also fine. It just means that you wouldn't have to dispose of water more often.

Industrial and residential dehumidifiers are both available for you, but if you've a small space, like let's say a 4x4 grow tent, then you should be good with a residential dehumidifier.

How To Choose The Right Size Dehumidifie For Grow Tent 

Don't worry about the calculation to know how big and how many dehumidifiers you should have as this is simple math.

Here's an example of what you've to keep in mind for you to know how your dehumidifier should perform:

If a plant should receive a gallon of water a day, then a small grow room of 20 plants, require 20 gallons of water a day. This is a total of 120 pints of water input in a day since a gallon is equal to 8 pints. When spread in a day's span, your grow room will need 5 pints of water an hour. A pint is equal to a pound of moisture, so a room with 20 plants needs 5 pounds of moisture an hour.

Dehumidifier sizes are usually ranging from 30 up to 300 pints. The bigger the size is, of course, the more expensive it'll be.

Sizing a dehumidifier for a drying room

If you are sizing a dehumidifier for your indoor drying room, you may be under the impression that finding a huge dehumidifier can speed up the drying process.

You may be right, a dehumidifier will certainly dry out your buds fast. But this actually isn't what you want!

When it comes to drying your cannabis, low and slow is the mantra you should live by. Trying to dry out your buds as fast as possibe will suck the flavor, potency, and enjoyment from them.

But, if you have a decent sized drying room, you may need some level of dehumidification. You need to know the wet weight going in, and the dry weight coming out. Then, simply divide by 2. Here is an example:

If you bring in 1,000 pounds of wet cannabis, you can expect it to weigh around 800 pounds dry (200 lbs of water weight).

Dividing this figure by two gets you 400, which is the pints/day needed from your dehumidifier. Then, you need to know the condition you are drying in, which should e around 65-70 degrees fahrenheit. If you don't want to take any risks, reach out to us and we can make sure you get exactly what you need.