Too Much Negative Pressure in Grow Tent [4 Ways to Fix]

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Too much negative pressure will negatively affect your yields. This is why the pressure needs to be maintained in the best and optimum levels at all times.

In this article, we will discuss 4 ways to fix too much negative pressure and everything you need to know about it.

Let’s get started.

Negative Pressure – What’s It All About

Before we discuss anything, it’s important to know that negative pressure is the best for your Grow environment.

Negative pressure means that more air is leaving your grow room than the air released from the room. With negative pressure, you can easily control temperatures, humidity, and carbon dioxide level in your grow room without much interference from air coming from outside.

One way to know that you have negative pressure is when you start noticing your Grow tent pulling in like a vacuum.

As mentioned, with negative pressure, its easy to control any condition in your grow room. So, one of the challenges that follow this benefit is maintaining the pressure at a negative level.

However, with fans, you can easily achieve this. You need an intake and extraction fan. The intake fan needs to be smaller or runs at a slower speed as compared to your extraction fan. This will create the difference in Grow tent pressure and hence maintain all the conditions needed in your grow tent.

Alternatively, you can use a vent inside the grow room to allow air in while you use a fan for extraction. This is among the best ways to achieve negative pressure in your Grow tent.

The Difference Between a Negative Pressure and Positive Pressure

The airflow in and out of the grow tent brings the difference between positive and negative pressure. As earlier mentioned, a negative pressure occurs when there is less air coming into the Grow tent than the air leaving the tent.

On the other hand, a positive pressure happens when there is more air entering your Grow tent than the air leaving the tent.

The difference can easily be observed.

When your tent has a positive air pressure, you will see the tent bow outward. This means that there is more air in the tent than there should be. The tent is experiencing some airflow imbalance.

We already mentioned that in the case where you have negative air pressure, the Grow tent would pull inside.

Benefits Of Negative Pressure in a Grow Room

Negative pressure makes life easier for your Grow room. Without any struggles, you can control the temperatures, humidity, and all other conditions in the tent.

Apart from that, you also get to control the unwanted odors from the tent.

With a negative pressure in your grow tent, plants get to thrive in favorable conditions. In the end, you get better yields that you could obtain from your Grow tent if the pressure were positive.

All these conditions ensure;

  • There is no mildew or mold formed on your plants
  • Unwanted chemicals and odor are taken out of your Grow room
  • You can easily control the conditions in your room for all phases of plant growth

Cons of Excess Negative Pressure

Negative pressure is good, but only if it’s not allowed to go beyond desired limits. When you notice the grow tent pulling itself inside, that means that the pressure is still in manageable stages and can easily be fixed.

However, in case you notice that the poles are beginning to bed or your grow tent starts wearing out, then at this stage, you need immediate action.

The negative pressure will reduce the volume in your grow tent. It will also make it very difficult for plants to breathe. Water and humidity in the grow room will also condense and affect your yield.

It won’t be a favorable condition for your Grow tent. You will notice the impact and the effect of the excess negative pressure.

But if you have already noticed these signs, don’t panic. There are simple ways you can apply to deal with excess negative pressure that you will get from your Grow tent.

Too Much Negative Pressure in Grow Tent

Ways To Reduce Too Much Negative Pressure in A Grow Tent

The only way you can deal with too much negative pressure is to increase the ratio of air, leaving your Grow tent to the air entering. However, this should be done carefully to ensure that you don’t create a positive pressure.

Remove more air from Grow tent but ensure the ratio of air coming from outside is lower than that leaving the Grow tent.

1. Use A Light-Proof Vent Flap

In the market, you will find some tents that come with built-in ventilation flaps. Most of these flaps are located at the bottom of the Grow tent.

So, when you notice excess negative pressure in your Grow tent, you can open one of the flaps and allow more air to come inside the Grow tent.

However, don’t open the flap when your Grow tent is on a dark cycle and there is light around it. We recommend that you open the flap during day time or when your plants are under a light cycle. Your plants won’t be affected by the light that comes from outside when the flap is opened.

2. Have an Extra Ducting Intake At the Bottom of Your Tent

You can have more ducting on your grow tent to bring more air inside. The main idea of having to duct at the bottom of your Grow tent is to ensure that it doesn’t allow any light in the Grow tent.

Again adding ducting to the grow tent would mean that more air will be allowed to enter the Grow tent than before. You can connect the ducting to intake fans to boost the amount of air drawn to the Grow tent by the Ducts.

For better and effective performance, create an ‘S’ shape for the ducting. This will minimize the chances of allowing light to pass through the ducting.

3. Use A Sufficient Intake Fan for Your Grow Room

One of the reasons why your Grow room attains a negative air pressure its because there is less air entering the Grow room than expected. This could be contributed by a small fan that you might have chosen for your Grow tent.

This is why you need to get a Grow tent fan that is adequate for your Grow tent. Get a fan that can draw in enough air to your Grow tent.

An active intake fan is usually needed for large fans.

You can buy fans with the following level of pressure for your Grow tent.

  • 4×4 Grow Tent: 245 CFM on average
  • 5×10 Grow tent: 650 CFM
  • 8×8 Grow Tent: 906 CFM
  • 10×10 Grow Tent: 1600 CFM

You shouldn’t buy a fan with lower CFM than your Grow tent. However, if the fan has a large CFM, you can adjust it. This is our Lat Tip.

4. Adjust the CFM Of Your Grow Tent

When you have less air coming into your Grow tent, you can easily deal with this by adding more airflow to it. Allow more air to come into your Grow tent.

However, to achieve this, you need to have bought a fan with a higher CFM than your Grow tent.

AC Infinity Cloudline S6 (Our Top Pick)

The fan is perfect for a mid-sized grow tent. It achieves an airflow of 351 CFM.

Key Features

  • Ideal strength for a mid-size room
  • Extremely quiet
  • The variable setting for efficient power consumption

The fan is available on Amazon. Click here to check the latest price and buy it today.

TJERNLUND M-67 Inline Duct Booster Fan

The fan attains a power output of 460 CFM. This means it can run for a long time without changing its performance.

Key Features

  • Made with strong and high-end materials
  • Efficient blade design to blog a huge volume of air
  • Super quiet fan

The fan is available on Amazon. Click here to check the latest price and buy it from Amazon.

Vortex 347 CFM S Line S-600 Fan 6”

With it, you will plant everything you would wish to plant in your tent or indoors.

Key Features

  • Mounts easily
  • Convenient with different speed controllers
  • A super quietest tent grow fan even at the highest speed

The fan is available on Amazon. Click here to check the latest price and buy the fan from Amazon today.

Hurricane Inline Fan

This makes it a perfect choice for anyone with a small grow area.

Key Features

  • Durable construction
  • Super Quiet Fan
  • Ease of installation

The fan is available on Amazon. Click here to check the latest price and buy it from Amazon today.

Terrabloom 10” Inline Duct Fan

It delivers a high airflow of up to 1065 CFM. At the same time, it’s cost-effective.

Key Features

  • Runs optimally for a longer period
  • Ultra-quiet fan
  • A powerful CFM coverage with a low energy consumption

The fan is available in the market. Click here to check the latest price and buy the fan today.

Parting Shot

If you want to get maximum yield from your Grow tent, you need to keep your pressure on the negative side. However, you must watch it to ensure it doesn’t go beyond the desired level.

In case you are dealing with excess negative pressure, apply the four techniques we have discussed in this article and you will note the difference.

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