What Size Dehumidifier for Grow Room to Keep Plants Healthy?

Raising plants in an indoor system asks for many balances to be done. And maintain proper humidity is one of them.

That being said, it’s not only about keeping grow room humidity level wet. It’s also about maintaining an optimal dryness. And that’s where the importance of selecting the right size of dehumidifier pops in.

See, if you’ve got your grow room dehumidifier calculator wrong, you’ll either have a too dry or too humid grow system. And it’s a gardening 101 that no one of these scenarios is good for growing.

So, give yourself the next few minutes to learn what size dehumidifier for grow room you should choose.

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.

How to Determine the Right Size of Dehumidifier for your Grow Room

Done with the basic introduction to the sizing properties of dehumidifiers? Now, it’s turns to figure out the right size for your grow systems.

Take some time to do these calculations stated below-

Factor 1: How Much Water Do You Feed to Your Plants?

It’s a hydroponics 101 that plants leave the nearby air with vapor, and this is the reason your grow room becomes humid. So, if you do an approximate estimation of how much water you feed to your plants, this will give you the amount(pints) of water you need to take off.

As an example, if you have 20 plants in your grow system, you have to feed at least 1 gallon of water to each of them in each day.

Now do these steps of calculating grow room dehumidifier

1-gallon x 20 plants= 20 gallons (the total water fed in 24 hours)

1 gallon= 8 pounds

20 gallons= 20X8 pounds= 160 pounds

1 pound= 1 pint

160 pounds= 160×1 pints= 160 pints

Verdict – you need to have a dehumidifier that is able to remove 160 pints of moisture from the air within a time span of 24 hours.

Summary line, the formula is-

“Required Dehumidifier Ability = Number of plants x gallons per plant per day x 8”

Based on this rule, do the simple math towards how much dehumidifier for grow room you need.

Factor 2: How Much Space You’re Able to Leave?

When it’s about indoor growing into a grow room or a hydroponics system, ground space is a premium. You’ve to place the plants, the entire plant setup, the fans, the air conditioners (portable ones) and so on.

So, when you’re thinking of determining the right grow room dehumidifier size, think about how much of the ground space you can provide it with.

Usually, convenient grow room dehumidifiers take a space of around 10 inches x 20 inches on the ground. Mini dehumidifiers, on the other hand, takes up to 10 inches x 15 inches on the ground.

So, there can be three scenarios-

There is ample space to house convenient dehumidifiers

Solution: The scenario already explains itself. It’s the grow room where adding an additional dehumidifier of convenient size won’t be an issue. So, you can go with one of the best dehumidifiers for grow room.

There is ample space to house mini dehumidifiers but not the convenient ones

Solution: In case you are with such a grow room dehumidifier placement issue, you have to buy multiple mini dehumidifiers, and house them within an equal interval. In case it’s the grow tent, then placing dehumidifier for grow room on the floor would be fine.

There is not enough space for either mini or the conveniently sized dehumidifiers

Solution: Well, this happens with tiny grow tent setups like 4×4, 6×6, etc. In those cases, you can either wall-half your mini grow tent dehumidifiers or go for a grow dehumidifier outside grow tent.

Such a setup will, however, decrease the efficiency of the dehumidifier. But as there are no other options left, you’ve to purchase a dehumidifier that’s a bit over the requirements of your grow room dehumidification.

Factor 3: The Height of the Grow System

Although, it’s not that much critical factor for grow rooms and convenient sized large dehumidifiers. But in case you are limited within a height of about 10 feet, this is important for you.

You see, one of the rules of placing your dehumidifier into a grow room is, you’ve to expose the face of the dehumidifier into the center of the room. When you’re limited with a short height like 10 feet or so, it’s hard to do with a mini-sized dehumidifier.

So, make sure that you’re using any additional support system that raises the height of the mini dehumidifier itself.

Bottom Line

So, that was our guide on how to calculate dehumidifier size for grow room and grow tent you should choose. Keep up the rules and factors in mind, and you’ll never end with a dry or humid grow room.

1 Comment
  1. Reply
    Silke Wagner April 26, 2020 at 2:27 pm

    When you are out looking for the perfect dehumidifier in the market, one of the most important things you need to keep in mind is that which size will be best suited for a dehumidifier for your grow tent. If you have a large grow room, you are bound to go for a large dehumidifier because if you go for a smaller one, its tank will be easily filled up and you will have to empty the tank very frequently which would not be an ideal use of your time. However, if you want the perfect sized dehumidifier for your grow room or your grow tent, then you will have to keep certain things in mind and use them to calculate the amount of moisture you need to get rid of. There are a lot of things that you will have to bear in mind before buying the perfect dehumidifier for your marijuana plants such as, the number of marijuana plants that you are growing and the moisture that is already present in the grow area. You will also need to take into account how much water you are feeding your marijuana plants as it is going to be as important as anything else to determine what will be the best size for a dehumidifier to do the best job of eliminating moisture from your grow area on a daily basis.

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