How To Lower Humidity In Grow Tent When Lights Off

How to Lower Humidity in Grow Tent When It’s too High

Home»Environment» The best way to lower the humidity in a grow tent when the humidity is too high 19187Views0 Humidity may be both a benefit and a disaster for an indoor grow system, depending on the situation. Just as with temperature, humidity has a significant impact on the quality and quantity of your indoor gardening harvest when it comes to quality and production. After everything is said and done, when the humidity in the grow tent rises to dangerous levels, it might result in the worst nightmare for a grower.

We hope you are not one of those people who would later come to regret spending all of their money, time, and effort because they were unable to deal with a scenario like this.

We’ve included both short-term and long-term solutions, as well as a list of causes that might result in damp air in the first place.

Why? Why? Why?

As a result, we’ve created a circumstance in which there is an excessive amount of humidity in the grow tent. The entire affair, on the other hand, did not happen out of nowhere. It must have had some cause for the high Rh level, and recognizing those reasons is critical to figuring out how to get the Rh level back down. Agreed? The following is a list of possible suspects:

Increased Transpiration

The size of a plant’s leaves increases in proportion to the size of the plant. Furthermore, it is a fundamental principle of botany that bigger leaves release more vapor into the atmosphere. In the event that you do not adjust your ventilation system to the appropriate level, the humidity will rise instantly. This might also happen if you suddenly increase the number of plants in a container or garden.

Open Water Surfaces

Open water surfaces are a direct source of water vapor into the surrounding atmosphere. A nutrient reservoir, a moist floor in a room, or any other container of water can be used as a water storage container. If it’s in close proximity to an oscillating fan, the airflow across the surface will cause more water to evaporate, and then bang! The laws of thermodynamics are in effect.

Too Humid Outside Environment

The average humidity in Alaska is 77.1 percent, whereas the average humidity in Florida is 74.5 percent. The list goes on with the states of Louisiana, Mississippi, Hawaii, Michigan, and so on and so on. (The whole report may be seen here.) This discusses in great detail why growing in a grow room in these types of environments is difficult. Any small crack or leak in the insulation system between the grow room and the outside environment may result in a sudden and unexpected increase in the relative humidity.


The soil will get soggy as a result of overwatering the plants, which will also push the leaves of the plants to release more vapor into the air.

Both damp soil and over-transpiring plant leaves have the potential to make the environment inside the grow tent uncomfortably humid.

High Humidity is Bad, Here’s Why-

A lack of humidity in a grow room can have a variety of negative consequences for the plants. However, having too much of it is not a good thing. When your grow environment becomes overly humid, here are some immediate results:

  • Unwanted biological development such as bud molds, powdery mildews, and other such organisms
  • Having an excessive amount of moisture in the air may encourage bud or blossom rotting, which won’t be seen until you’re at the harvesting stage. First, by inhibiting the capacity of the plant to take up CO2, and then by restricting photosynthesis
  • The plant’s ability to transpire further is hampered by vapor saturation of the air. This results in a drop in the total metabolic rate of the plant
  • Plants prefer humid air while they’re young, and less humid air when they’re old, according to the USDA. If the plants continue to develop under high humidity as they mature, the rate of their growth and the quality of their health will be hindered.

How High is ‘Too High’ for Grow Room Humidity?

As we all know, the degree of humidity fluctuates from one development stage to the next. As a result, it is not possible to designate a definite “Rh Percentage” as a distinguishing factor between an optimal and an excessively high humidity level. However, the general rule of thumb is that the entire range of humidity in a grow room should be less than 60%. A rise in the relative humidity level above 60% can cause a number of crop-related problems, as we described in detail in the preceding section of this article.

The Correct Humidity Levels for Different Grow Stages

The plant’s roots begin to develop at this stage and will continue to grow for a while. As a result, a high amount of humidity is required. Humidity domes are frequently used to raise the relative humidity (RH) of the approaching air above the plants.

Vegetation: Rh 40-60%

Because growing plant leaves need a sufficient amount of water in the air, the humidity level must be elevated. Additionally, a percentage of the water intake is accomplished through the roots of the plants. However, because they haven’t fully formed yet, leaves must continue to take in water.

Flowering: Rh 35-50%

This is the point at which high Rh begins to manifest itself in negative ways. As a result, it is critical that the humidity does not rise from this point on. Molds, rotting buds, and other unpleasant things will begin to appear if this is not done. To ensure that the flowering stage begins successfully, the relative humidity should be maintained between 40 and 50 percent. However, after the buds begin to produce a crop, farmers reduce the percentage to 35-40 percent. And this must be done gradually, so that there is no significant, rapid decline in the Rh.

Harvesting/Drying: 30-40%

Crops begin to dry at this point, which leads to the harvesting of the crop. However, we must maintain a humidity level of 30-40 percent in order to prevent the buds from drying out too quickly. Some growers prefer to maintain a little higher humidity level (50 percent) in order to allow their buds to dry more slowly. This, in any case, enhances the overall quality of the cured buds.

Germination/Cloning Vegetation Flowering Harvesting/Drying
75-85% Rh 40-60% Rh 35-50% Rh 30-40% Rh

How to Decrease Humidity in Grow Tent/Room?

When it comes to figuring out how to reduce humidity in a grow room or room, things aren’t always easy to cope with. Any action will require sufficient time to bring the Rh down. As a result, you must stick to the shortest routes available. The few of solutions that we’re about to cover are designed specifically for circumstances like this. Here’s everything you need to know-

Use A Dehumidifier

It should go without saying that in order to reduce humidity, you will need to rely on our trusted ally, the grow room dehumidifier.

Prior to purchasing a dehumidifier, take a moment to consider the appropriate size for your grow room layout before making your purchase. So, what exactly qualifies as a decent dehumidifier that can remove the exact amount of humidity that you require? Some points to think about are listed below.

  1. Dehumidifying capacity is critical, and it should match the requirements of your grow system exactly. According to the manufacturer, it is intended to absorb and expel the same quantity of vapor that your plants exhale via their leaves. There is a limit to how much may be held in a pint
  2. You should check to see that your dehumidifier can be connected to your drainage system if you live in a humid climate. It should have a water tank that is enough in size. It should be equipped with an automated timer or an automatic shut off mechanism (when the tank is completely full)
  3. It should be considerate of the power bills’ budget.

Once you’ve selected the appropriate size dehumidifier, you’ll need to ensure that it is installed in the proper location. Also, avoid connecting these dehumidifiers to electrical extension cords if at all possible. The following is our preferred dehumidifier for the grow room: GDM30 from Ivation The following is our preferred dehumidifier for the grow room: hOmeLabs Dehumidifier for 1,500 square feet that is Energy Star rated

Use An Air Conditioner

Knowing that the temperature and humidity of a grow room are intertwined is not a surprise. When the temperature rises, the capacity of the air to contain water vapor increases as well, and you will see a direct increase in the Rh levels in your room. As a result of decreasing the temperature, you will be able to eliminate a significant amount of humidity from your grow tent or growing environment. Having said that, selecting the appropriate size of air conditioning units is critical. Otherwise, it will either result in condensation or will be unable to maintain control over the temperature and humidity levels in the room.

Passive Ways

When it comes to smaller grow systems, such as 44, 55, and 88 grow tents, utilizing a dehumidifier or air conditioner is not a suitable alternative for reducing humidity. Fortunately, there are a number of passive solutions that are effective in dealing with this problem in indoor grow systems. We’ve compiled a list of three actionable passive methods for accomplishing this. Take a look at this-

Boost the Ventilation Up

When it comes to passive methods of decreasing the humidity level, increasing air circulation is at the top of the priority list. One of the primary reasons of excessive humidity buildup in your grow room is the failure to properly vent damp air out at a sufficient rate. Simply said, substituting the humid air for fresh, ambient outside air will lower the Rh percentage by a significant amount. In the event that you find yourself in a high humidity condition, the following steps should be taken to improve ventilation:

  • When it comes to passive methods of reducing humidity, increasing air circulation is at the top of the list. Another important factor in excessive humidity accumulation in your grow room is the inability to exhaust damp air at a sufficient rate. Just to put it another way, substituting the humid air for fresh, ambient outside air will lower the Rh percentage. If you find yourself in a high-humidity condition, the following steps should be taken to improve ventilation:

Use A Thermostatically Controlled Block Heater

Do you have a high level of humidity in your grow tent at night? Increases in Rh levels and condensation are more likely to occur during the dark hours as opposed to the light hours, according to research. The temperature decreases as soon as the lights are turned off. When the temperature drops sufficiently, moisture will begin to accumulate around the lights, which is referred to as humidity fluctuation in this context. Remedy? When the lights in your grow room are turned off, use a thermostatically controlled block heater to keep the temperature near to the level when the lights are turned on.

Defoliate the Plant Leaves

We’ve already noted that when plant leaves develop in size, they become a more significant source of water transpiration into the surrounding atmosphere. Result? The humidity in the grow chamber rises quickly. You can defoliate some of the exceptionally huge plant leaves as a passive solution for bringing the humidity level in the grow tent down.

Whenever you are removing leaves, make sure to leave enough for the plants to continue their usual operations, such as photosynthesis. By comparison, it is a relatively inexpensive method of lowering humidity in grow tentas that works fairly well.

Things to Do to Avoid Further Raise in Humidity

What can I do to permanently reduce the humidity in my grow tent? Here are some steps you may do to keep the humidity in your ingrow tent from rising any further:

Don’t Depend on One-dimensional Ventilation

One of the fundamentals of humidity control is that, if appropriate ventilation is provided throughout the grow room, the air will never get saturated with water vapor. The oscillating fans alone will not be sufficient to ensure that this occurs. Because they can only lower the temperature of the plant canopy, they are not very effective. So, what is the best way to create a multi-dimensional ventilation system? As a result, here are some recommendations: –

  1. If you’re growing in a tent, make sure there are many intake holes. In the event of a room, source air should be provided by more than one intake fan. Maintain appropriate air circulation across the plant canopy, including the bottom (with floor fans) and top (with wall-mounted oscillating fans) sections. Allowing the CO2-rich, heavy air to accumulate on the floor is not recommended.

Deduce Exposed Water Surfaces

It’s a very easy and inexpensive hack to do, but it turns out to be really successful in terms of lowering the humidity in the grow room. And that is to determine whether or not there are any exposed water surfaces in the grow chamber. How did these open water surfaces get there in the first place?

  1. Water that is stagnant yet does not puddle on the ground
  2. Reservoirs for water

To deal with the first, you must make certain that a sufficient drainage system is in place throughout the whole grow system. For the second, just place covers over each and every water reservoir you have in the room to bring the situation to a close.

Insulate Your Grow Space from Outside Humidity

Occasionally, you will notice that the humidity level continues to rise regardless of how much effort you put out after placing it down. Perhaps this is due to the fact that your indoor garden is in close contact with an excessively humid outside environment. It’s possible that the location where you reside has more humidity than usual, just like it does in New Mexico or Colorado. Commercial growers frequently utilize barriers such as foam insulators and other similar materials to prevent this from occurring.

Use Soil That Absorbs Vapor

The use of soil that can absorb water and retain the Rh beneath the grow tent can be a useful step in eliminating humidity in the grow tent. Sandal soil is an excellent example of this type of soil. Make certain, however, that your plants will not have any difficulties growing in such mediums.

Use The Right Size of AC Units

Both big and undersized air conditioning systems have the potential to cause an increase in temperature and humidity. With large air conditioning machines, the dead band is quite brief, resulting in an increase in humidity in the surrounding air. And, on the other side, small air conditioning systems cause wilting, which is a concern for indoor plants. One of the factors that might cause a troublesome environment for the plants is a high degree of humidity. What’s the gist of it? Always make sure that the air conditioning units are the proper size so that they can operate consistently for the greatest amount of time.

See also:  How Often Should You Tent For Termites In Hawaii

Keep an Eye on Your Humidity Level

Using this method does not constitute a ‘prevention’ to lower humidity in a grow tent. However, by utilizing a hygrometer, you can keep track of the exact humidity level that your tent or room is experiencing. In the market, there are thermometer-hygrometer combos that may be purchased.

You can kill two birds with one stone if you have one of them hanging on the wall of your grow tent. To ensure that the humidity in your grow tent does not get too high, here are some of our favorite digital thermometer-hygrometer combos.

  1. ThermoPro TP65 Digital Wireless Hygrometer
  2. AcuRite 00613 Indoor ThermometerHygrometer
  3. ThermoPro TP65 Digital Wireless Hygrometer

I’m Saleh, and I’m a blogger that enjoys doing home improvement projects on the side. is my tiny corner of the internet where I can communicate what I’ve learnt first-hand, particularly in the field of home repair. The most recent posts by smsaleh (see all)

How To Lower Humidity In A Grow Tent (Without Spending A Ton)

Plant maintenance and growth is a combination of art and science. This is also true in the case of cannabis production. As you get more experience in the field, you will have a deeper understanding of the ‘art’ component of the equation. The same may be said for the’science’ component of the test. However, in contrast to the arts, you may research science and truly get it right from the beginning. When it comes to the science of cannabis cultivation, heat and humidity are two of the most significant aspects to consider.

It is your responsibility to keep those levels up.

Today, we’ll look at one part of this: what to do if the humidity in your home is excessive.

How To Lower Humidity In A Grow Tent

Cannabis is not a fussy plant in the least. It can thrive in a wide range of environmental conditions. However, if you provide it with the optimal circumstances, it will reward you with far larger and higher-quality harvests. Even the most ideal conditions aren’t important to the plant, which doesn’t have a preference. It prefers a comfortable room temperature and average humidity. So there’s nothing exceptional here. The optimal temperature and humidity levels, however, do alter as the plant matures and becomes more established.

Different Growth Stages Need Different Humidity

Humidity levels should be increased throughout the early stages of growth to ensure proper development. During this period, plants thrive under excessive humidity. However, as plants progress through their development phases, the humidity level needs to be reduced. The optimal humidity values for each stage of plant development are listed below.

  • The percentage of seedlings and early vegetables is 70 – 75 percent, the percentage of vegetables is 50 – 70%, and the percentage of flowers is 40 – 50%.

In most cases, you won’t have to worry about lowering the humidity while you’re relaxing. In fact, depending on your location’s climate, you may need to take steps to increase the humidity in your grow tent. This, however, changes during the flowering process. You may find it difficult to keep the humidity levels down during the day. Unless, of course, you continue reading. Then you’ll be able to figure out exactly what to do. But first, let’s take a quick look at why it’s important to keep humidity levels under control.

Why Lower Humidity In Your Grow Tent?

Mold, fungus, rotting buds, and mildew can develop in your grow tent as a result of high humidity. It even has the effect of slowing the development of your plants. The most prevalent is a condition known as bud rot, which is comparable to the grim reaper for plants, appearing in your grow tent and wreaking havoc on your plants. It appears as a white powdery material at first, then becomes gray, and then becomes black as it matures. If your buds become infected with bud rot or powdery mildew, they are rendered unusable and must be discarded.

What does bud rot have to do with decreasing the humidity in a grow tent?

However, bud rot and other forms of mold and mildew aren’t the sole culprits in this case. Aside from the external reasons, there is an internal cause for wanting to limit the moisture content of the air from becoming excessive.

Internal Health Effects Of High Humidity

External factors such as bud rot and the mold and fungus that might develop as a result of excessive wetness are not the only possible difficulties. There is also the possibility of an interior issue developing. If the air is saturated with moisture, your plants’ roots will not be able to absorb as much water as they should. The nutrients required by your plants will be depleted if your plants do not drink enough water from their roots. Nutrient insufficiency leads in buds that are less powerful and more unhealthy.

Lowering Humidity In A Grow Tent

The good news is that lowering humidity levels is not that difficult to do. However, there is a good probability that you may have to spend some money. You will almost surely want at the very least a ventilation system, and maybe even an air conditioning unit or a dehumidifier. You’ll need ventilation and maybe air conditioning anyhow to keep the temperature under control, so it’s not really an extra expenditure. Dehumidifiers, on the other hand, are not pricey.

Get A Dehumidifier

Wouldn’t it be great if science could come up with a machine that was particularly intended to remove moisture from the air, and all you had to do was plug it in and walk away from it? Well, such a remarkable machine does exist, and you can find it at your local home improvement or drug store. You may also purchase one online, such as this one (good for a small tent). A dehumidifier is the most straightforward solution to the problem of excessive humidity, but they may be expensive if you have a large tent or a large room.

Commercial Grade Dehumidifiers

If you have a large company or if you are doing this for a living, you should definitely consider investing in a commercial-grade dehumidifier right away. Even if the little ones designed for everyday use are ideal for small tents and hobby growers, they do not let you to regulate the humidity level. They can only be turned on or off; there is no in-between. While this is sufficient for the majority of individuals, it is insufficient when there is a considerable amount of money at stake. It is possible for a commercial grade dehumidifier to continuously measure and adapt its operation depending on whether it needs to remove moisture or whether it needs to rest and let the water vapor to gather.

If you are not concerned with the ability to’set it and forget it,’ or if you have a small company, you will not require a commercial dehumidifier to meet your requirements.

Ventilate Your Grow Tent

If you can get fresh air into the tent from the outside, this can assist to reduce the humidity, provided you do not reside in an exceptionally humid climate zone. Of course, if you’re going to be bringing in fresh air from the outside, you’ll also be exhausting air from within the tent, so plan accordingly. In fact, with tiny tents, all that is required is that you blow air out of the tent. In order to compensate for the negative pressure created, additional air must be drawn in. In order to exhaust the air in your grow tent, you’ll need a good inline fan for it.

Because humid air is heavier than dry air, if humidity is a significant problem but temperature is not a significant one, you can consider installing an exhaust fan at a low setting.

By leaving greater space between the plants, you may also improve circulation among the plants themselves.

As a result, there is greater space for air to circulate, and the lower branches do not form buds in the first place. You will have a greater yield if you do not use them. Make certain you simply utilize the best weed trimming scissors available. The bad ones will not cut neatly as they should.

Do Not Water More Than Necessary

Overwatering your plants will almost always result in issues. When your plants receive too much water (particularly in areas with poor drainage), it can lead to nutritional deficiencies and root rot, which can cause them to become anemic and sickly. Excess water also contributes to excessive humidity in the air. When it comes to watering your plants, make certain that you are following scientific principles. A much of water might be detrimental to your plants’ health. As a result, you are included.

How Much Water Is Too Much?

This is a subject that warrants its own book (and there are already a plethora of them available!). However, because it is important for minimizing the humidity in your tent, we will go through the fundamentals here. This might vary greatly depending on your growth medium (soil or other types of media) and drainage system. As a general rule, you should water your plants until the soil is well saturated, then allow the soil to dry completely before repeating the process. Assuming you have normal soil with adequate drainage and growing pots of moderate size, this amounts to one thorough watering every 2-3 days.

There is a general rule of thumb that can be useful to you.

The aim is to totally soak your plants on a regular basis rather than watering them only a tiny bit every day.

In addition, it almost certainly causes the air to become excessively humid.

Lower Grow Room Temperatures

The terms relative humidity and temperature are synonymous. Temperatures that are higher than optimal are OK as long as the humidity is lower than ideal. In the same way, vice versa. This means that you may, in essence, compensate for greater than optimal humidity by maintaining lower than ideal temperatures. That being said, this is really just a smart option if you’re having trouble getting the humidity levels under control. It is far preferable to really reduce the humidity while maintaining the temperature where it should be at all times.

Consider An Air Conditioner

The most convenient method of lowering temperatures is to use an air conditioning unit. As previously said, not only is this a crucial element of maintaining the health of your plants, but it is also a simple and effective approach to reduce the relative humidity in the air. It is possible to purchase units that stand alone or are on wheels, removing the requirement for them to be permanently fixed to the wall. This is ideal for use in tents. They have an exhaust tube that has to be routed out of the tent via an aperture in the side of the tent.

The ability of the air to contain water will be reduced as a result of cooling it and circulating it around the room. The colder the air, the less’space’ there is for water to live in its natural environment.

Lower Grow Tent Humidity: Final Thoughts

Higher humidity levels are ideal for vegging, but during flowering, and especially during the later stages of blooming, you must substantially reduce the amount of moisture in the air to ensure a successful harvest. Not doing so will result in a less productive (and, in some cases, wholly unproductive) yield. There are a variety of approaches that may be used to reduce the humidity in your grow tent, but the most effective are enough ventilation and optimal circulation. It’s also crucial to keep your body temperature under control.

How to Control Humidity in Your Grow Tent (4 Easy Ways) – Easy Guide

The most recent revision was made on February 2, 2022. It is completely normal to use a grow tent to house a cannabis plant that is in the process of growing. The process of setting up a complete room such that it is suited for plants might be time-consuming and not really worth it for a tiny grow-op. However, due to the fact that a grow tent is a much more contained environment than an open space, there may be a few concerns that arise. The most pressing of them is the dilemma of how to regulate humidity in a grow tent.

If this is left unchecked, it might result in growth problems or molds that can destroy the plants.

How to Control Humidity in a Grow Tent

Source: cannabispromoter, courtesy of Pixabay Because of a variety of factors, optimal air circulation in any grow tent is essential for the best results. Even with water molecules connected to it, hot air always climbs to the top of the atmosphere. As a result, our CO 2sinking is restricted to the bottom of the grow tent, behind the plant canopy, where it cannot be used. Fans are the most obvious option in this situation. Many people make the mistake of placing small oscillating fans at the top or sides of the room; however, they perform a poor job of blowing through the plant canopy and stirring up the CO2 at the bottom of the chamber.

They circulate the air, which aids in drying out the environment and transporting the beneficial CO 2 up into the plant canopy.

2. Ventilation

Once the fundamentals of air circulation have been established, the following stage is to determine how excessively humid air may be expelled from the grow tent. Fortunately, there are a plethora ofexhaust systems available that are specifically designed for this function. These function by removing stale, humid air from the grow tent through an exhaust vent and introducing fresh air into the tent through an intake vent, which should be located at the bottom of the tent. As the exhaust fan exhausts the air from the tent, fresh air is drawn in through an open intake port in the structure.

Many versions of exhaust fans may be programmed to only turn on when the humidity reaches a specified level, or to turn on and off on a simple timer.

Other solutions include installing carbon scrubbers on the exhaust to eliminate any scents that may be present. The use of this method also aids in temperature regulation, while alternate methods may be required in especially warm or cold tents.

3. Air Conditioning

Because of the nature of the lighting system utilized in the grow tent, things can become really hot within it very rapidly. When specific conditions are met, the space becomes essentially a mini sauna. Portable air conditioners are the most effective alternative in this situation, albeit the size required may vary significantly depending on the size of the grow tent. A correctly sized air conditioning unit will not only cope with high temperatures, but it will also assist in extracting a significant amount of water from the air.

It is one of the most effective techniques to increase yields is to keep their environment somewhat temperate (in the 70°F to 80°F range) and consistent.

See also:  How To Make Tent Name Cards

4. Dehumidifiers

In most small to medium-sized grows, air conditioning, air circulation, and a good exhaust system should be sufficient to keep the humidity in a growtent within tolerable ranges. However, this is not always the case, particularly when anything goes wrong. Individually owned humidifiers will not suffice in this situation. They become overflowing much too soon, and they are just not designed to manage the large volumes of water that your cannabis plants produce. The possibility of purchasing an industrial-scale dehumidifier is likewise not a viable option for most farmers, mostly because to the high cost.

This, on the other hand, is not a really bright concept.

Most portable dehumidifiers, depending on the size of the tent, will perform well as long as they are utilized in conjunction with other instruments.

  • Read more:Top Picks for the 5 Best Dehumidifiers for Grow Tents in 2021 – Reviews

A Message on Insulation

No one of the humidity-control measures discussed above will be effective unless the tent is adequately insulated. When installing modifications such as exhausts or intakes, care should be given to verify that any holes are the right size for the tubing that will be utilized in the installation. A leaking grow tent may and will cause problems with humidity levels in the environment. Aside from the occasional gaping hole in the side of the tent, a well-constructed grow tent should have little issue allowing your tools to do the tasks for which they were intended.

Harnessing the Power of Humidity – Blog

When plants are young, a high level of humidity is good. You don’t want them to lose too much water at this stage since they don’t have any roots to help them absorb water. Aim for a relative humidity of 70 to 80 percent (depending on temperature – see table) A high level of humidity encourages plants to spend the majority of their energy on establishing roots and leaves rather than attempting to regulate their relative humidity.

  • Roots develop more quickly, health increases, and growth is significantly more robust.

Create a humid propagation environment with the help of a propagator.

All of the propagators that we sell are equipped with ventilation panels that can be opened and closed to adjust the humidity level.

Veg growth

Humidity should be decreased throughout the vegetative phase. Aim for a relative humidity of 50 percent to 80 percent (depending on temperature – see table) Now that the plants have established some roots, you want them to begin transpiring. As water is shed via the leaves, nutrients and water are pulled up from the ground through the roots of the plant. Upon germination, plants begin to produce leaves and branches at a rapid rate. This reduces the amount of transpiration stress placed on each leaf, allowing you to operate at a lower humidity.

When plants lose an excessive amount of water, they pull more up via their roots.


Buds begin to develop during the blooming stage. Now is the time to lower your humidity levels in order to lessen the likelihood of rot. Aim for a relative humidity of 40-60 percent (depending on temperature – see table) Temperature and humidity meters should be used to keep an eye on things. Make certain that your ventilation is up to par in order to keep your humidity levels from becoming too high. If it doesn’t work, you can invest in a dehumidifier.

During lights off, your temperature drops. This means your air can hold less water. To counter this, you may have to adjust your humidity.

9 Effective Ways: How To Lower Humidity In Grow Tent?

The plants in Mark’s grow tents had developed an abnormal growth pattern one day when he returned from work, and Mark spotted it. He discovered several plants that had powdery mildews and bud molds, as well as those that had rotting blossoms. He couldn’t believe what he was seeing. What was the source of Mark’s difficulties? Mark, on the other hand, is not alone. Every year, thousands of people are confronted with the same problems. These kind of difficulties in agrow tent are believed to be caused mostly by extreme humidity, according to industry experts.

They were able to accomplish this just by efficiently managing the moisture in the tent.

After reading this article, you will have a good understanding of why it is necessary to minimize humidity, what generates a humid atmosphere, and how to deal with excessive humidity levels.

Why Lower Humidity?

First and foremost, we must define what humidity is. Ordinarily speaking, humidity refers to the amount of water vapor present in the environment. Humidity is not in and of itself a bad thing. When the temperature rises over a certain threshold, it poses a hazard to tent planting. The recommended temperature and humidity for growing tents are 20-30 degrees Celsius and less than 70% relative humidity, respectively. The following are some of the hazards of excessive moisture:

Pests And Diseases

Pests and bacteria are attracted to high humidity, which results in illnesses such as bud molds and powdery mildews. Solving humidity concerns is a common solution to these difficulties.

Effect On Metabolism

Excessive humidity impairs a plant’s capacity to absorb carbon dioxide from the air.

As a result, the plant is unable to perform proper photosynthesis, which has an impact on the plant’s entire metabolism.

Rotting Of Buds And Flowers

Humidity levels that are too high pose a serious hazard to plants. It causes damage to portions of the plant that are relatively fragile, such as buds and flowers. High humidity grow tents are notorious for causing bud rot and bloom rot, which can be fatal.

Inhibit Growth Rate

The ability to effectively manage humidity is essential for the optimal development of plants. The growth rate would be unsatisfactory if moisture could not be controlled adequately.

Low Water Intake Of Roots

There is already an enough amount of water vapor in the highly humid air. As a result, plants are unable to evaporate the water. They have a tendency to consume less water than is necessary.

Low Plant Yield

Plants are unable to carry out their normal metabolic processes when the humidity level exceeds the optimal range. This has an impact on the results of plants. One of the most significant objectives of any planting is to produce a high yield of goods. As a result, it is critical to maintain an appropriate humidity level.

What Causes High Humidity?

Before we can figure out how to minimize humidity in a grow tent, we must first figure out what causes excessive humidity. The following are some of the most common reasons of excessive humidity:


While it is necessary to water plants as they are developing, overwatering may be extremely detrimental. It can sometimes cause the soil to become more moist than usual, which increases the amount of humidity in the air.

Free Water Surfaces:

Water surfaces exposed to the elements are a direct source of humidity. As water evaporates, the surrounding environment becomes more humid. If there is a water pot, you should make sure it is covered.


Transpiration is a natural mechanism in which plants exhale water vapor into the atmosphere to cool themselves. Water is taken up by plants from the soil. In addition, it makes the air more humid.

External Environment:

A natural process through which plants emit water vapor into the atmosphere is known as transpiration (transpiration). Soil water is taken up by plants as food. As a bonus, it increases humidity in the air.

No. Of Plants:

Humidity is increased when there are too many plants in a limited place. When planting, it’s important to keep in mind how many plants you’ll be putting in your grow tent.

Size Of Grow Tent:

Large grow tents do not become as humid as tiny grow tents because of their size. It also boils down to the number of plants you are cultivating in a given space.

Effective Ways: How To Lower Humidity In Grow Tent?

In order to minimize humidity levels, we must first address the underlying reasons of high humidity. We will not all be confronted with the same kind of issues. You must first determine the nature of the position you are in. Follow the recommendations and learn how to regulate humidity in a grow tent. However, if you are interested in a low-cost method of lowering humidity in a grow tent, please see this link.

Do Proper Ventilation

Increased ventilation will help to reduce humidity levels in the environment. The tent’s ventilation system ensures that the trapped air within the tent has a connection with outside air. Airflow may be achieved by the use of fans.

Do Proper Insulation

The high temperature of a location might be a contributing factor to high humidity levels.

As a result, you must determine whether or not your grow plant has adequate insulation. This will protect the plant from getting wet from the outside.

Use Air Conditioners

The high temperature of a region can be a contributing factor to the high humidity levels therein. In order to ensure that your grow plant has adequate insulation, you should inspect it. This will protect the plant from becoming wet from the outside environment, which is beneficial.

Use Dehumidifiers

If you routinely experience excessive humidity, a dehumidifier is the best option for you. Many different types of dehumidifiers for grow tents are available on the market. They are available in a variety of sizes and powers. You must choose the one that is the most appropriate for the size of the grow tent.

Remove Stagnant Water

The presence of a stagnant open water source will raise the relative humidity in the tent. As a result, in order to minimize humidity, you must eliminate free water sources.

Apply Water-Absorbent Soil

There are many different types of soils available on the market that absorb water. When these soils are applied to plants, the humidity will be reduced. As well as promoting plant growth.

Reduce Plant Density

Because of the high density of plants, there will be a lot of dampness. As a result, in order to lessen humidity levels, you must limit the number of plants in a grow tent.

Control Overheating Lights

The usage of lights that generate heat might cause temperatures in the tent to rise significantly. It is necessary to regulate the temperature in order to regulate the humidity.

Defoliate Plants

Vapors are released in greater quantities by large leaves than by little leaves Occasionally, removing the bigger leaves might help to reduce humidity. Growing plants in grow tents is a delicate process that requires great care. It necessitates extensive and time-consuming efforts. High humidity has the potential to undo all of your hard work. As a result, it would be beneficial if you gave this topic your whole attention. If you know how to reduce the humidity in a grow tent, you will have a big advantage over others.

  • Then you have to figure out what the primary factors are that are generating the excessive humidity.
  • However, if they do not function well, you must be prepared to spend money on a humidifier or an air conditioner.
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Question: How To Lower Humidity In Grow Tent Without Dehumidifier

How to Reduce Humidity in a Grow Tent is explained here. It is important not to overwater your plants. Make use of a dehumidifier to keep the environment within your grow tent comfortable.

Check the density of your plants. Remove any standing water. Increase the number of fans in the room to improve ventilation. Make air holes to allow for ventilation. Make a purchase of an air conditioning unit. Insulate and seal the interior of your grow tent.

How do I lower the humidity in my grow room?

To summarize, in order to maintain the humidity in your grow room under control, you must:Ensure that it is adequately sealed and insulated. Maintain a specified temperature range and keep an eye on the illumination. Increase the amount of cold air coming in. Make certain that no stagnant water pools develop. Make use of a dehumidifier that is the proper size.

How do I dehumidify my tent?

How to prevent condensation in a tent Open the vestibule door and roll back the rain flap to allow humid air and wet exhalations from your breath to escape. During the night, take any damp clothing or shoes out of your tent. Cooking and boiling water should be done outside your tent to prevent raising the humidity level inside.

What can I use if I don’t have a dehumidifier?

Natural Dehumidification Techniques for Your Home Moisture should be absorbed. If you place pots of calcium chloride in problem areas of your house, you should notice a significant drop in humidity levels very quickly. Make sure to ventilate your home. Indoor plants should be removed. Showers should be shorter. Dryers with a vent. Repair any leaks. Install a solar-powered air conditioner. Change to dry heat sources if necessary.

Does a carbon filter remove humidity?

Carbon filters have a little dehumidifying effect.

What is an alternative to a dehumidifier?

In a humid environment, turn on a fan to help minimize the amount of moisture in the air. Keeping the air flowing helps to limit the amount of water vapor produced. If the room has a window that can fit a fan, you may use it to increase the ventilation in the space. Purchase a type that has an exhaust setting so that you may evacuate stale air before introducing new air.

Why does my tent get wet inside?

What is the source of condensation in tents? Because of the presence of people, heaters, and a lack of ventilation, the air temperature in the tent might become warm and humid. During the condensation process, moisture condenses into liquid form when the heated air within the tent comes into contact with the comparatively chilly tent fabric.

How do I lower the humidity in my lights?

Make certain that your ventilation is up to par in order to keep your humidity levels from becoming too high. If it doesn’t work, you can invest in a dehumidifier. When the lights are turned out, your body temperature lowers. This indicates that your air has a reduced ability to contain water.

What humidity level should my grow tent be?

A high level of humidity in your grow tent is also undesirable. Humidity levels that are too high can cause mold to grow on damp portions of your setup, as well as on the actual plants themselves. Moldy plants do not thrive in high humidity, so keep your humidity levels between 40 and 70% at all times.

How do I lower humidity without a dehumidifier?

How to lower interior humidity levels without using a dehumidifier. Make sure your room is well ventilated. The use of air conditioning. Fans. Replace the filters in your furnace and air conditioner. Showers should be shorter and cooler. Dry your clothing outside on a line. Open a window a crack or two. Houseplants should be placed outside.

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Can baking soda be used as a dehumidifier?

Considering that baking soda absorbs moisture, it may be used to assist dehumidify your home.

As an added plus, it is really affordable. Pour the mixture into small bowls and cover each with a thin towel.

Why is my humidity so high in grow tent?

When the temperature within your grow tent is greater, more water vapor will be able to be held in the air. Heat causes water to travel more quickly through the air, resulting in a greater level of humidity in the air.

Will mold grow at 55 humidity?

When the relative humidity is more than 55%, the conditions are favorable for the formation of black mold. Water leaks and other household issues, such as burst pipes, allow water to enter the home and create an atmosphere conducive to the growth of black mold. If a minor leak stays undiscovered for an extended period of time, the mold might continue to develop unchecked.

How do you bring humidity down?

What Can I Do to Lower My Humidity Levels? Make Use of Your Air Conditioning. Make Use of Your Exhaust/Ventilation Fans Actively Shower in a cooler environment. Pipes that are leaking should be repaired. Maintain the cleanliness of your gutters. Take Your Laundry Outside to Dry. Purchase a dehumidifier. House Plants Should Be Relocated.

Do inline fans reduce humidity?

Installing an inline fan in your grow tent is a common technique for controlling humidity levels in your growing environment. As an added precaution, it is recommended that you install some oscillating fans within the tent to aid in the circulation of any stagnant humid dead air that may be present.

Is 70 humidity too high?

According to research conducted by the Building Science Corporation, humidity levels of 70% or higher near to a surface might cause substantial harm to the property. In interior environments, the Health and Safety Executive advises that relative humidity be maintained between 40 and 70 percent, whereas other experts propose a range of 30 to 60 percent.

What will absorb moisture in a room?

2. Make use of dehumidifiers and exhaust fans throughout the house. If the humidity levels in your home are consistently at or over 65 percent, it’s time to invest in a dehumidifying system. Plants that absorb moisture should be grown. On very humid days, refrain from boiling water. Remove Your Clothes from the dryer. Maintain the cleanliness of your air conditioning filters. Showers should be colder and shorter. Replace the carpet in your home.

How do you control temperature and humidity in a grow tent?

Methods for Lowering Temperatures Air exchange and overall airflow should be increased in your growth environment. A easy trick: turn the lights off during the day and turn them back on at night. When growing with High Pressure Sodium (HPS) lights, consider utilizing a cool tube to keep your plants cool. Install an air conditioning unit (air conditioners will also help to reduce humidity).

Where should I put my dehumidifier in my grow room?

Place your dehumidifier at the specified distance away from the wall to prevent the machine from becoming “choked” by the wall. Additionally, locating it away from direct airflow from an air conditioner or heater will aid in airflow management.

Will turning up the heat reduce humidity?

Raise your thermostat a few degrees: Heating Portland houses in the winter helps to keep excess moisture at bay.

In order to avoid turning your home into a sauna, you should avoid making it too humid in the first place. This will only exacerbate the situation. When heating your house, use dry heat and make sure there is enough ventilation.

What size dehumidifier for 5×5 grow tent?

Any dehumidifier that can remove up to 40 to 50 pints of water from the air per day is ideal for a 55 grow tent.

How to Lower Humidity in Grow Room Set Up

Anyone who has grown cannabis will tell you that the most crucial component in producing high-quality cannabis flowers is maintaining consistent temperature and humidity. Climate, which is composed of temperature and humidity, is the single most important variable influencing density, potency, and overall cannabis yields. In the past, we’ve spoken about how young plants and clones require greater levels of humidity. However, as the adage goes, they don’t stay youthful indefinitely. The development of a plant’s roots signals the beginning of the three subsequent plant cycles: Vegetative, Flowering, and Late Flowering.

In order to ensure optimum nutrient uptake, mold and fungal avoidance, as well as improved resin growth on your colas, you must gradually reduce the humidity in your growing environment.

Stage of Growth Humidity Lights-On Temperature
Seedling Stage 65-70% 68-77 F°
Vegetative 40-70%* 71-82 F°
Flowering 40-50% 68-79 F°
Late Flowering 30-40% 64-75 F°

*Decreased by 5% every week until the right levels are achieved.

What Is Humidity?

It is truly “Relative Humidity” that we are referring to when we talk about relative humidity (RH). Water vapor concentration is a comparison between the quantity of water vapor present in the air and the amount of water vapor the air could store at a certain temperature before it turned into moisture. Warmer air can store more water vapor than colder air, and this is the most crucial thing to remember about air temperature. Because of this, as the temperature lowers, fog forms: even if the water vapor levels stay constant, the lower temperature allows for less water vapor suspension, resulting in fog formation.

Because relative humidity (RH) is a measure of humidity in relation to temperature, increasing the temperature while maintaining the same water vapor levels reduces relative humidity.

The alternative method of adjusting relative humidity is to increase or decrease the amount of water vapor in the air while maintaining constant temperature.

temp down, RH up), but altering vapor levels at a fixed temperature has no direct effect on relative humidity (temp up, %RH up |

Controlling Humidity

Assuming you have your temperature under control with adequate ventilation and cooling, let’s have a look at what we can do to manage humidity levels in order to produce the ideal environment for healthy cannabis crops. To understand how to regulate humidity, we must first understand where it is coming from and why it is there. The relative humidity levels of the external air that is vented in will be different from the inside air. This will change depending on the place, the season, and even the day.

In the last instance, any standing water in your grow chamber will evaporate into the air, increasing the amount of water vapor in the air.

This is especially true when taking into consideration how tough it may already be to maintain acceptable temperatures when dealing with dozens of 1,000 watt bulbs and the heat they emit.

As a result, the most effective method of lowering relative humidity is to eliminate water vapor directly. You’ll need a dehumidifier to accomplish this.

Why You Need a Commercial Dehumidifier

Many first-time growers are aware of the need of controlling humidity levels, but often make the error of attempting to save money on this critical piece of equipment. Consequently, instead of purchasing the appropriate instrument for the task, they purchase a dehumidifier meant for household use, which is by design inefficient when compared to the amount of work it is performing and simply isn’t constructed to manage the burden. Get a commercial-grade dehumidifier if you’re planning any big growth projects.

  • Choosing to jump a few pages ahead and getting it done correctly the first time with a business dehumidifier is another.
  • No matter how hard you try, humidity levels will not miraculously decrease on their own.
  • if you put in the effort to make them great.
  • To further maintain consistency, make sure you incorporate redundancy into your grow room design from the beginning to the end of the process.
  • In fact, if Murphy has taught us anything, it is this: nothing is impossible.

Humidity: Finding the Sweet Spot for Your Grow Room

This is fantastic since it indicates that your plants are breathing properly and that there is no lack of water throughout your grow room orgrow tentseasily. Different degrees of humidity are required at different phases of a plant’s existence in order for it to seed, veg, and blossom in the proper manner. That said, you shouldn’t have a humidity level in your grow room higher than 70% at any time, so if you’re approaching that level, you might want to think about where the moisture is coming from and what you can do to avoid it from damaging your grow.

Where’s all that grow room humidity coming from?

Moisture content is a measure of the quantity of water vapor present in the air. Despite the fact that water vapor is constantly present in the air, the temperature of your grow room has an impact on the presence of humidity in your garden:

  • The higher the temperature in your grow room, the greater the amount of water vapor that can be held in the air. Heat also causes water to travel more quickly through the air, covering a larger surface, resulting in increased humidity levels in the grow room. When there is a lot of moisture and it gets hot (as in swamps), it becomes sticky and humid because there is warm water in the air and it is moving swiftly. Conversely, the lower your grow’s temperature, the less water vapor it can store. When there is little heat, the circulation of water vapor slows down, covering less surface, and resulting in decreased humidity in the grow chamber. Lower temperatures can be challenging because too much moisture can result in moisture build-up and/or freezing
  • Too little moisture can result in a bone-dry environment, similar to that of the desert in winter.

The carbon dioxide (CO2) that plants naturally emit can raise the temperature of the grow room, which will result in moisture accumulation, which will boost the humidity. If you utilize CO2 in your grow, the humidity level in your grow room will climb even more. Grow equipment, including as grow lights, can also contribute to the increase in temperature in your grow space.

When the temperature in your grow room is high and the lights are turned off, the temperature will drop. After a significant drop in temperature, you may see moisture accumulating around your lights, which is a symptom of relative humidity variation.

Grow room humidity can’t be that bad, can it?

While a little more or less humidity in your grow room won’t make much of a difference, keeping it between 40 and 70 percent will. However, if you have too much humidity in your grow chamber, you’re in for a world of trouble:

  • The accumulation of moisture and an excessive amount of humidity in your grow room might result in rotting, such as bud rot or bloom rot. Because the findings won’t be seen until after harvesting, and by that time, it will be too late to correct any faults, this is the worst case scenario. You may notice white mold forming on your leaves, which prevents them from absorbing light and water. White mold will consume the nutrients from your plants and, if not caught in time, might leave your harvest ineffective.

In addition, too little humidity in the grow chamber is detrimental to plants:

  • Stasis in growth can occur if your plant is concerned about becoming dehydrated. This can result in the closure of the stomata, which means that the plants will be unable to take in much (if any) water. Deficits in nutrients- Plants love to take in water vapor through their leaves, but when there isn’t enough water in the air, your plants will have to receive their water from another source: their roots. It is inevitable that nutrients will follow your plants when they are thirsty and absorbing a lot of water into their roots. A high level of nutrient uptake is detrimental to your plants, and you may see nutrient burn on the ends of your leaves as a result.

Temperatures and Humidity Levels at Each Stage of Development Just like we discussed before, plants flourish in a variety of humidity levels throughout their lives at all stages of development. Consider the following as an example of where the humidity level in your grow room should be located: Seedlings/Clones: 70-75 percent of the population Humidity- Because your plants require time to establish strong root systems, the bulk of the water they receive is through their leaves. When your plants are newborns, you must ensure that there is sufficient moisture in the air to ensure that they are adequately fed.

  1. For vegging plants (up to flowering), maintain a humidity level of 50-70 percent in the grow room.
  2. Because plants will still need to absorb moisture via their leaves throughout the early phase of their vegging cycle, you’ll need to maintain relatively high humidity levels (60-70 percent) at this time.
  3. Humidity in a blooming plant’s growing environment: 40-50 percent of the population Humidity- Flowering plants require a suitable climate in which to grow, one that is neither too hot nor too cold.
  4. As you come closer to harvest, you’ll progressively reduce the temperature down to around 40 percent when you’re ready to clip, lowering it by 5 percent every 2-3 weeks until you reach the desired harvest temperature.
  5. You want to make sure that the environment isn’t too humid in order to avoid the development of mold.
  6. When harvesting, make sure your plants are in a location where the humidity levels are consistent and the temperature and heat are around room temperature and heat level.

Adding and removing humidity from your growing environment There are a handful of things you can do to change your humidity levels if you find yourself leaning toward being too damp or too dry while checking your humidity levels; There is too much humidity: If the air is overly humid, you may use a Dehumidifier to remove the extra moisture from the air.

Make careful to check to see when the humidifier is full and empty it if it doesn’t have a drainage mechanism, especially if the unit doesn’t have one.

Whether you just open a window or use a duct fan to drive the moisture out of the grow space and outside, it is important to do it often.

There isn’t enough humidity: Adding a humidifier to your grow space may significantly improve the humidity in your grow space.

This will allow you to know when to stop pumping the air full of moisture. Remember that humidity levels and temperature interact with one another, so raise the temperature when you want a humid atmosphere and lower the temperature when you want less moisture in the air to keep it humid in there.

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