How to Increase Humidity in A Grow Box

Before evaluating the various ways through which you can increase the humidity in a grow box, its essential to understand the importance of optimal humidity. Most of the time, plants consume water through the roots. However, when the water level is low, the plants consume water from the surrounding areas through the air. The dry and low humidity leads to the production of HPV (High vapor pressure), where plants lose water to the surrounding environment. Other than causing plants to lose moisture, low humidity also makes up for the perfect environment for the development of bugs. 

Plants require the evaporation process and heat from the sun to pull in water. In most cases, water moves through the plant body by using potassium salts. However, the pulling of water, otherwise referred to as transpiration, occurs when the sun hits leaves, and causes water to evaporate. This process helps to cool the leaves and pull more water to various other sections of the plants such as the leaves. 

Some plants tend to be humidity-sensitive and might have many pores or small leaves that only have few cells. Due to their compact nature, these sections of the plant might have poor vasculature, which might compromise the movement of water. Small cell tissues make it easy for water to escape to the air, thus increasing the likelihood of plant dehydration. When humidity levels in a grow room decrease, the ability of the air to hold water improves and the process of transpiration.

Tips for Improving Humidity in A Grow Box

Farming methods have come a long way over the years, and the best way to develop a stable environment is to ensure the room is well sealed. Commercial farming technology and production companies are aware of this fact and employ various techniques to develop a thick weather barrier around grow boxes. This is a critical technique for regions that usually experience low outdoor humidity levels. 

More so, this approach also helps to prevent factors such as humidity, sunlight, and wind from compromising the growth of the plant.

Control the Room Temperature

Temperature is among some of the leading factors to consider for every plant owner, especially when using light to control the heat. However, when controlling the temperature, using a consistent approach is crucial. Usually, growers tend to go for large air conditioning systems, which can sometimes be ineffective. Even if you place the grow box in a relatively warm room, any increase in temperature is likely to affect the performance of the grow box. Thus, putting the machine in a cool and dry place can improve the performance of the machine. 

For most people, the gut feeling is to purchase a large AC system to help regulate the humidity levels. If the system is too large or small, its likely to lead to temperature fluctuations, which might affect plant growth.

Two key factors cause temperature fluctuation in air conditioning systems. These are the deadband and short cycling factors. The deadband is a 2 to four-degree temperature range around your preferred temperature range for the plants. At the upper limit of the deadband, an AC unit cycle on to help maintain a cool environment. However, at the lower end, the machine might shut off to prevent any frosting issues. Based on the nature of this band, an overly large AC system might run in short cycles, which might lead to the overconsumption of power. It may also cause an unstable growth environment, where temperatures and humidity increase drastically over a given time duration. 

Oversized ACs are not the only challenge facing plant growers. For instance, when an AC machine is too small, the temperature might increase gradually as time passes by. As the temperatures increases, withering can occur, which is a significant issue affecting many types of plants. 

Therefore, the best approach to exceptional temperature and humidity control would be to categorize the AC power consumption. The AC will run best on longer on consistent cycles for long durations, to avoid compromising the deadband.

Seal and Insulate the Room

If you are trying to grow plants in a damaged grow box, you are doing it wrong! One of the key factors when growing plants indoors is to ensure the grow box is in top condition. Any product with leaks or any form of damage is likely to affect the plant growth. Thus, ensure the grow box is well sealed and working in top condition.  If you live in places where the outdoor humidity falls to low levels, you may have to be more cautious about your plant`s humidity.  Factors such as sunlight, wind, and humidity all impact the growth of your plants. These plant growth factors and many others have a notable effect on the temperature.

Air Movement Is Important

Even if it holds water, humid air tends to be lighter than the remaining aspects of air, which means that its prone to random movement. However, elements such as CO2, which are essential for plant growth, are much heavier. Thus, it’s important to maintain optimal air circulation levels in your grow room. Using tools such as oscillating fans might not be sufficient for your grow room in this case. These machines will only cool the temperature on the canopy but lead to poor air circulation. The ideal air circulation occurs through the bottom, top, and walls. 

plant in grow box

Using floor fans can be an excellent solution. These fans can pull air through a plant canopy, thus providing a unique environment for plant care and with exceptional humidity levels.

Manage any Standing Water

Perhaps the simplest and most convenient approach for managing humidity would be to eliminate standing water. Most growers overlook this perspective, but it’s crucial to ensure that overwatering does not occur in the grow room. Any stagnant collection of water will increase the humidity levels in a room considerably. Furthermore, you also need to cover the reservoirs in a grow room to maintain the water positioning. It’s easy to come across grow rooms where the control system is well-calibrated, but the humidity levels fluctuate. Most of the time, its because a large pool of standing water is close to the growing area.

Use a Proper Dehumidifier Size

While it might sound obvious to use this type of machine for controlling humidity, its an area that many growers try to cut corners. Instead of going for a small and cheap 70-pint unit, go for a proper size machine. For instance, residential dehumidifiers are not suitable for grow rooms due to various reasons. The first reason is that these machines are not productive and might use lots of power. Thus, you might get ballooned power bills, with a tool that is not able to accommodate the workload of the grow room. Before you can purchase a dehumidifier, ensure that you evaluate your farming needs, and the functionalities of specific brands.


Using a grow box can be a reliable solution for growing plants such as herbs and more. However, similar to any modern farming setting, the plants have received the best care, to ensure the best harvests. Factors, such as humidity, warmth, and water, are all important you’re your plants. Thus, learning about how to increase humidity in a grow box can be a great way to take the health of your plants to the next level.

Whereas an entire grow room is large, a grow box is a relatively small compartment, which makes it simple to control the interior conditions for plant growth. Unlike the air surrounding it, humidity tends to be much more prone to movement and can sometimes rise to the top of a room. Thus, choosing a proper dehumidifier brand can go a long way in improving the humidity in a room.

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