What are dehumidifiers and how to use them when growing weed?

Even for experienced cannabis growers, it can be difficult to keep the humidity in the grow room balanced. After all, you have a whole bunch of plants in a compact space. Even with a window open and a fan on to circulate the air, it can still get too humid. This can leave you with problems like mildew and bud rot, making your grow more of a headache than a pleasure. Considering the risks involved you probably want nothing more than to simply remove the water from the air. But you can’t do this yourself, but a dehumidifier can do the job at the touch of a button. We will show you how such a device works and how you can use a dehumidifier in maintaining the right humidity level.

What are dehumidifiers? How do they work?

You don’t come across them very often, so don’t blame yourself if you are not familiar with these devices. A dehumidifier is an upright electronic device with special vents and fans. With it, the device sucks water from the air and collects it in a removable bucket. In a sense, a dehumidifier is the opposite of a humidifier. Although dehumidifiers vary in size, you can assume that the most suitable device for you is about a meter tall. However, you can also find them in small sizes, so they don’t have to take up a lot of space. You also don’t need any controls, nor do you need to perform any other actions to make the device work. All you have to do is turn it on and adjust the settings. Once you have done that, all you have to do is throw away the water once the bucket is full. It’s that simple!

Benefits of a dehumidifier

As simple as they are, dehumidifiers offer fantastic benefits when growing cannabis plants.

  • Good for the general health of the grow room

For starters, a dehumidifier generally improves the environmental conditions in the growing space. As a result, problems like mildew and bud rot are much less likely to occur.

  • Natural protection against mold and mildew

These improvements also mean that you don’t have to use chemicals to protect your plants. This is not only good for the quality of your cannabis plants, but also saves you a lot of time and money.

  • You save time on ventilation

Humidity is often the main reason you need to ventilate your grow room. With a dehumidifier you do not have to spend so much time on this. This time can then be spent on other things you need to do.

  • Stable conditions

Ventilation can cause big fluctuations in heat and cold. By ventilating less, the temperature in your growing space remains more stable. This reduction in temperature fluctuations will allow you to save perhaps 50% on your energy costs.

Dehumidifiers for home use versus dehumidifiers for cannabis

You might be looking for any dehumidifier right now. However, there are some important differences between home dehumidifiers and dehumidifiers specifically designed for cannabis growing.


You may notice that home dehumidifiers are usually quite small. While this may seem fine for compact grow rooms, such a dehumidifier often doesn’t work as well in these spaces. This is because a dehumidifier for cannabis is specifically designed to serve a room full of plants. In addition, these devices can absorb a proportional amount of water. Because of this, dehumidifiers for cannabis are often larger and heavier than those for home use.


More important than size is the area that the dehumidifier can extract moisture from. Since home dehumidifiers are meant for smaller spaces, they do not have such a long range. The range is much smaller compared to dehumidifiers for weed. The latter are in fact specifically designed to extract moisture from a very standard growing space.

Special features for growing weed

Finally, it is worth mentioning that dehumidifiers for cannabis cultivation have additional features that can come in handy during cultivation. For example, do you suffer from a lot of noise in the growing room? Then you can buy a dehumidifier with a compressor that dampens the noise. Are you often busy? Then you might be interested in a dehumidifier with an automatic shut off function. This way you can decide when to empty the device.

How do I install a dehumidifier in my grow room?

Now that you know what types of dehumidifiers there are you might also want to know how and where to install them in your grow room. With this information you can also choose a dehumidifier that best suits your needs.

1. Calculate range

To get started, spread out a tape measure and calculate the area of your growing space. With this knowledge, you can focus on specific dehumidifiers that are suitable for the dimensions of your space.

2. Most optimal place

There is an art to placing the dehumidifier in the right way. The device does not work equally well in all places. Ideally you should leave a lot of space around the dehumidifier. If you place the device too close to your plants they could dry out. If on the other hand you place the dehumidifier too far from your weed plants it will probably not work properly.

3. Room shape and airflow

The final factor to consider when making your choice is the shape of your space and the way the air flows through it. For example, in certain areas the airflow is less than in others. This is probably where you need to extract more moisture.

Dehumidifiers in the drying room

A dehumidifier is not only useful during the grow itself. Since cannabis buds are at risk of going moldy during the drying process it is wise to use the dehumidifier during the drying process as well. This will probably get you done in a week instead of the usual two weeks. After you have dried your buds you can use the dehumidifier again for your next grow!