The Best Dehumidifier for Grow Tent & Where to Place it
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Whether you’re growing weed for a hobby or are a larger-scale cannabis cultivator, humidity holds no prejudice on whose crops it destroys.
For many indoor growers, a dehumidifier is a necessary part of the process.
Are you unsure of what size dehumidifier for grow tent to use or where to place a dehumidifier in grow room for the best results?
I’m going to go over all you need to know to determine the best dehumidifier for grow tent at your home or business.
And if you haven't picked out your grow tent yet, be sure to check out this massive grow tent buying guide by THCoverdose.
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Table of Contents
The Best Dehumidifiers
2200 cubic feet is a good industry standard for a 16 X 16 room.
However, you might need to get a few once you start adding in plants and lights.
With that being said, this is a light and easily portable dehumidifier.
It’s also very strong and works well in balancing humidity levels.
Using Thermo-Electro Cooling instead of a compressor, this is a very quiet dehumidifier.
Another huge plus, the Powilling Mini Dehumidifier lasts a long time.
Seeing as this product is so tiny, the reservoir tends to fill up often.
This product does automatically shut off when it reaches its limit.
However, that limit happens often.
So be sure to check to see if it’s running.
Otherwise, your plants might not be in proper relative humidity levels.
What makes the JHS such a valuable tool for growing weed at home is that it’s a 3-in-1 system.
The JHS Portable Air Conditioner is a fan, air conditioner, and dehumidifier.
One annoying aspect of the JHS is that it doesn’t come with a tray.
You need to unplug the water trough and empty a few times a day.
However, you can set the unit up so that it constantly drains into a larger container, sink, or out the window.
A great feature about the JHS is that it has a wi-fi enabled remote control.
All you have to do is download the app, and you can see the current humidity levels of your room.
From there, you can decide whether you to turn the mechanism off or keep it running.
Like the Powilling, the Hysure has Thermo-Electro Cooling technology that allows for quiet operation.
While the Hysure does prove to be effective for smaller grow areas, it takes a long time to get going.
Therefore, if you have a lot of patience, this dehumidifier will do the trick.
The Hysure will surely benefit from power in numbers.
Getting additional dehumidifiers and layering the times they run will go a long way in assuring that the humidity levels within your grow tent environment remain consistent.
This is one of the simpler ones when it comes to its interface...that's because there isn't one.
It’s a plugin and go system.
All you need to do is push the button, and the Hysure will automatically shut off when the reservoir is full.
What stands out right away about the Eva-Dry Renewable Mini Dehumidifier is that it looks like a carbon monoxide detector.
With that being said, this compact thing packs a serious punch.
Eva-Dry is 100% renewable, with no energy needed to power it.
That means no batteries or power cords.
The way it works is that the Eva-Dry has moisture meter crystals inside.
When they are dry, the indicator changes to orange.
When they are wet, it changes to green.
Green means the crystals need to be renewed.
When this happens, you remove the Eva-Dry from your grow room and plug it into an outlet.
Once plugged in, it charges a non-toxic crystallized silica that renews the unit.
This unique technology means there is no water to empty.
Also, the Eva-Dry comes with a 10-year guarantee, making this the best dehumidifier for grow tent longevity.
This is a good dehumidifier for cannabis because it operates best at 59 degrees F to 86.
These temperatures cover the ultimate minimum and maximum temps you should have for your cannabis plants.
One thing to keep in mind is that this dehumidifier struggles to work efficiently when temperatures reach lower numbers.
Therefore, even if you are putting it outside of 4x4 grow tent, you must regulate the temperature of the room housing the tent.
While this mini dehumidifier might be a little bit louder than some others on the list, it still has the Thermo-Electro Cooling system that makes the noise level tolerable.
Seeing as this is such a small dehumidifier, you have to run it all the time to make a difference in your grow tent truly.
Also, it only covers up to 1200 cubic feet.
So, you would have to invest in more of these units.
That’s not necessarily a bad thing because it allows you to cover more area of your cannabis plant as it reaches the vegetative and flowering stages.
What is Humidity?
To understand how to control humidity, it’s good to have a clear understanding of what humidity is.
For any living organism to survive, it needs sunlight.
When you have a grow room, grow lights mimic the sun, giving nutrients to the plant.
Just like when you sweat under a hot sunny day, plants respire at elevated temps.
As this happens, water secreted from the plant interacts with the air and creates a gaseous state of water.
This is water vapor.
Humidity is the amount of water vapor present in the air.
Grow Room Temperature and Humidity Control
You hear so much about two things that play a crucial role in your cannabis plant growth.
Temperature and humidity.
The two go hand-in-hand in many ways.
When the heat goes up in a grow room, there will be more humidity.
Since your grow room is indoors, moisture can get trapped in a room.
This is especially true if you have even the best AC for your grow tent.
Why is Humidity Control So Important?
When your plants are small, humidity is easier to control.
It’s as cannabis plants grow bigger and require more water when the humidity issues pop up.
With bigger plants comes bigger canopies.
This leaves more room for moisture to become trapped.
As these water vapor particles fester, it can lead to bud rot and powdery mildew.
When these conditions transpire, they will affect your yield.
However, powdery mildew and bud rot can also be fatal to the whole plant.
How Do Dehumidifiers Work?
To get a better grasp on what is the best dehumidifier for grow tent, you should understand how these tools work to decide which is most suited for your environment.
Dehumidifiers may come with many bells and whistles.
Bare bones, they all work the same way
A fan inside of the dehumidifier pulls in the grow room air.
When the air goes through the dehumidifier, it comes into contact with cooling coils inside of the mechanism.
This lowers the temperature of the moist air, eliminating water vapors.
How to Get Rid of Water
The extracted water is collected in a reservoir attached to the unit.
Some of the best dehumidifiers have an area where you can connect a hose to the unit.
That way you can guide the hose to a water drain or out a window.
A lot of dehumidifier models come with an auto-shut off.
This is handy in case you forget to empty your reservoir.
The dehumidifier will detect that the reservoir is near capacity and will turn off automatically.
This is a handy perk to avoid spillage.
Managing the Grow Tent Humidity
Another common feature in the best dehumidifier for grow tent is a tool known as the Humidistat.
This function works much like a thermostat on a furnace.
Once the humidity level you need for your cannabis plants is reached, the dehumidifier will turn off.
Having a humidistat is a great way to save on energy costs.
Reading Humidity Levels
When discussing humidity levels, I am talking in terms of relative humidity.
The scientific explanation for relative humidity is the ratio of current water vapor density in comparison to how much water the air can hold at that given temperature.
This is where the whole hot air holds more water vapor than cold air does situation comes into play.
As a reference point, if there were a reading of 100% relative humidity, it means that the air has reached its max water vapor level and can’t hold onto it anymore.
Therefore, it creates a possibility of rain.
Best Humidity Levels for Cannabis Plants
Just as each temperature brings on different humidity levels, the different stages of cannabis plant growth requires their humidity levels and temperatures.
Each grow tent will have their own unique needs.
That’s because altitude, climate, nutrients, lighting, watering, and so many other factors have an impact on the health of your plants.
Therefore, you need to pay attention to how your plants are reacting to your methods and adjust accordingly.
While there’s no exact answer as to what the best humidity levels for cannabis plants are, I can give you a good ballpark estimate to start with.
Humidity Levels for Seedling Stage
Since the roots aren’t already established in the seedling stage, they prefer higher humidity levels.
That’s because the roots need as much water as possible.
Therefore, a high humidity of level between 65 to 70% will create excess moisture in the air.
As the leaves start to grow, the high levels of humidity in the air allow the plant to draw in more water and nourish the roots.
To reach this sweet spot for seedling humidity levels, you need to get your room temperature within 68 to 77 degrees F.
Humidity Levels for Vegetative Stage
When your seedling starts to break the surface, you have reached the vegetative stage.
This monumental moment means your plants’ humidity needs have changed.
Each week you can lower the humidity levels around 5%.
Pay attention to your plant’s reactions to the change and adjust accordingly.
Do a little each day, so they don't go into shock.
An acceptable range for humidity at this point can fall anywhere between 40% and 70%.
Temperatures During Vegetative State
While you want to bring the humidity levels down slightly, you also want to bring the temperatures up.
This makes the vegetative state a delicate dance.
Ideally, you want your grow tent temperatures to hover between 72 degrees F and 82 degrees F with the grow lights on.
This allows for the roots to absorb more water, while higher evaporation levels cool the leaves.
Humidity Levels for Flowering Stage
As buds begin to sprout, you need to give your plant a little extra TLC.
First and foremost, you must lower your humidity levels to 40% to 50%.
Whatever you do, don’t allow them to get over 60%.
The leaves are starting to get bigger and will trap as much moisture in the air as possible.
You also want to start lowering the temperatures during the flowering period.
With the grow lights on, you want to be between 68 degrees F to 77 degrees F.
Humidity Levels Pre-Harvest
One to two weeks before harvest, your plant will go through a late flowering phase.
While you don’t need to take any action for the survival of your plant, making a few adjustments may better your overall yield, appearance, and flavor.
Try to lower the humidity level of your grow room as much as possible.
Ideally, you can get as low as 30% to 40%.
To achieve this, you might need to drop the room temp anywhere between 65 degrees F and 75 degrees F.
Also, make the differences in temperatures between daytime and nighttime much starker than you’ve been doing throughout this whole process.
What Size Dehumidifier for Grow Tent?
In all actuality, if you are growing plants as a hobby, you can purchase any run-of-the-mill dehumidifier that you'd get for a stinky, old basement.
Most of these units pull at least 150 pints of water from the air, which will suffice.
You need to make sure that you have no other prior black mold, fungus, or moisture issues lurking in your house.
Also, be sure the area is properly ventilated and avoid overwatering.
All of this will go a long way in decreasing the amount of water vapor floating about in the air.
Getting a Commercial Dehumidifier for Grow Tent
You can probably get away with using a regular humidifier until you reach six to eight grow lights.
Anything beyond that, you will want to consider upgrading to a bigger unit.
When you reach this number of lights, you are looking at far more moisture in the air.
For the survival of your cannabis plant, you will need a dehumidifier that will take at least 300 pints of water vapor out of the atmosphere.
When to Invest in More Than One Dehumidifier
A general rule of thumb when determining your dehumidifier layout is figuring out how to much dehumidification a room needs without anything inside of it.
Then adjust as you add more lights and grow more plants.
Depending on the number of crops, it may be in your best interest to get two units that take 225 pints of water vapor out.
This would allow you to find a sweet spot of 400 pints of dehumidification that is essential when you hit between 10 and 12 grow lights.
Where to Place Dehumidifier in Grow Room
No matter if you are using one everyday dehumidifier or a dozen commercial sized dehumidifiers inside of a grow room, you need to place these units in the correct areas for them to realize their fullest potential.
To give adequate coverage, allow even spacing between the dehumidifiers.
Make sure the side of the dehumidifier with the filters is the one that’s facing the source of the moisture (the plants).
If your grow room is large, try to place the dehumidifier in the center of the room.
No matter where you place it, make sure there is enough space on either side of the dehumidifier that allows airflow in and out.
Can I Put a Dehumidifier in My Grow Tent?
If you are running your operation in a 4x4 grow box, I wouldn’t recommend a dehumidifier inside. It will just take up room. If your humidity is too low, try putting a bowl of water inside.
Best Dehumidifier for 4x4 Grow Tent
The humidity of the room that is home to your grow tent affects your plants much like the humidity outside of your own house affects you. Therefore, you need to control it.
Place the dehumidifier in the center of the room, with the filters facing the grow tent. Then adjust the amount of water in the bowl inside of the 4x4 grow tent as needed.
Best Dehumidifier for Grow Tent
Now that you know the importance of dehumidifiers and how to use them let's find the best one for your needs. Don't forget to check out this guide we wrote up on humidifiers for your grow room if your levels are too low.
Last update on 2019-09-20 / Affiliate links / Images from Amazon Product Advertising API