Greenhouse Humidifiers: Creating a Lush Environment

By: Evan Scoboria, Last updated: June 28, 2023

The delicate balance of temperature and humidity in a greenhouse can significantly impact the health and productivity of your plants. One essential tool in maintaining this balance is a greenhouse humidifier. This device helps control and increase the moisture level in the air, providing an optimal growing environment for your plants. This article will explore the vital role of humidity in greenhouse plant health, how a greenhouse humidifier operates, and its numerous benefits. We'll also offer tips on using and maintaining a greenhouse humidifier and guide you in choosing the right one for your needs. Whether you're an amateur gardener or a seasoned horticulturist, understanding how to utilize a humidifier in your greenhouse effectively can help ensure your plants flourish.


Understanding the Role of Humidity in Greenhouse Plant Health

Humidity refers to the amount of water vapor in the air, and it plays a crucial role in greenhouse plant health. To understand this, it's essential first to understand how plants function. Plants primarily absorb water through their roots, which they use for various biological processes, including photosynthesis, to convert light into energy. However, plants also lose a significant amount of water through their leaves in a process known as transpiration.

In a greenhouse, maintaining the proper humidity levels is critical. When humidity is appropriately managed, it can prevent excessive transpiration, leading to plants losing water faster than they can absorb it, leading to stress or wilting. On the flip side, overly high humidity can lead to condensation on plant surfaces, which can, in turn, encourage the growth of mold, mildew, and other pathogens detrimental to plant health.

Also, humidity can affect the plant's ability to take in carbon dioxide, a vital element for photosynthesis. In environments with low humidity, the stomata (small openings in the leaves through which plants take in carbon dioxide and release oxygen) may close to reduce water loss, subsequently limiting carbon dioxide intake.

A relative humidity level between 50% and 70% is ideal for most greenhouses. However, the specific requirements can vary depending on the type of plants you are growing, the current stage of their growth, and the climate in your region. Consequently, a greenhouse humidifier can help maintain these optimal conditions, promoting healthier growth and larger yields.

How a Greenhouse Humidifier Works

A greenhouse humidifier functions by adding moisture to the air, thereby increasing the relative humidity within the greenhouse environment. While the exact mechanics can vary depending on the type of humidifier, the primary goal remains the same: to maintain ideal humidity conditions for plant growth and health.

One common type of greenhouse humidifier is the evaporative humidifier. This type works by drawing dry air from the greenhouse and passing it over a moistened wick or filter. As the air moves over the wet surface, it picks up moisture and is expelled back into the greenhouse, raising the overall humidity level.

Ultrasonic humidifiers, on the other hand, utilize high-frequency sound vibrations to create a fine water mist that is then released into the greenhouse. These humidifiers are highly effective and tend to be quieter than their counterparts, but they also require distilled water to prevent the dispersion of mineral particles.

Steam or warm-mist humidifiers heat water to its boiling point, producing steam which is then released into the greenhouse. They are highly effective at rapidly increasing humidity but consume more energy due to the heating element.

Regardless of the type, most greenhouse humidifiers have a built-in hygrometer or can be connected to a separate humidity sensor. This allows the humidifier to monitor the relative humidity in the greenhouse and automatically adjust its output to maintain the desired levels. Some advanced models can even be connected to a central control system, allowing for automatic adjustments based on the time of day, the current weather, or the specific stage of plant growth.

Benefits of Using a Greenhouse Humidifier

Mist filled Greenhouse

A greenhouse humidifier offers numerous benefits that contribute significantly to your plants' growth, health, and yield. Here's a closer look at some of these advantages:

  1. Improved Plant Health: Humidity plays a crucial role in plant transpiration, the process by which water is moved within the plant and ultimately released into the environment. By maintaining optimal humidity levels, a greenhouse humidifier aids in efficient nutrient absorption, enhanced photosynthesis, and improved plant health.

  2. Higher Yields: Humidity levels directly influence plant growth rates and productivity. Plants can achieve optimal growth with the proper humidity levels maintained by a humidifier, leading to increased crop yield.

  3. Disease and Pest Prevention: Low or high humidity can lead to various plant diseases and pest problems. A humidifier can help keep the humidity at the right level, reducing the risk of these issues.

  4. Ideal for Tropical Plants: A greenhouse humidifier is necessary to grow tropical plants that thrive in high humidity. It allows you to create an environment similar to the plant's native habitat, promoting lush, vigorous growth.

  5. Prevents Leaf Wilt: Insufficient humidity can cause plant leaves to wilt and turn yellow. The leaves can retain moisture and stay vibrant and healthy with a humidifier.

  6. Energy Efficiency: Greenhouse humidifiers often use less energy than other forms of humidity control, making them an energy-efficient choice for large greenhouses.

Investing in a greenhouse humidifier can have a significant positive impact on the growth and health of your plants and, ultimately, on the success of your greenhouse. Whether you're a hobbyist or a commercial grower, maintaining humidity is critical to greenhouse management.

Choosing the Right Greenhouse Humidifier

When choosing the right greenhouse humidifier, there are several factors to consider. One of the most important aspects is the size of your greenhouse. You'll want to choose a humidifier that can efficiently cover the entire area. If your conservatory is large, you may need more than one unit or a commercial-grade humidifier.

Another aspect to consider is the type of plants you're growing. Some plants require higher humidity levels than others. Tropical plants, for example, need a high humidity level, while others may require less. This may influence the type of humidifier you choose.

The features of the humidifier should also be taken into account. Some models come with built-in hygrometers to measure humidity levels and adjustable settings to ensure you provide the right amount of moisture for your plants. Other models may have timers or automatic shut-off features, which can be particularly useful for maintaining constant humidity levels, especially when you're not around to monitor the greenhouse.

The ease of cleaning and maintenance is another factor to consider. Some models are easier to clean than others, and maintaining your humidifier is essential to prevent mold growth and ensure the unit continues to function well.

Lastly, consider your budget. The price of humidifiers varies greatly, and while you may not want to choose the cheapest option, you also don't need to break the bank to find a quality humidifier that will meet your needs. Always compare different models, read reviews, and research thoroughly before deciding. A well-chosen humidifier can be a significant asset to your greenhouse, fostering healthier, more vigorous plant growth.

Tips for Using and Maintaining a Greenhouse Humidifier

Using and maintaining a greenhouse humidifier properly can significantly affect its effectiveness and longevity. Here are some tips to ensure you get the most out of your greenhouse humidifier:

  1. Placement: Position the humidifier so its mist evenly distributes throughout the greenhouse. Avoid placing it directly beside plants, leading to over-humidification and potential water damage. You may need multiple units or fans to ensure even humidity distribution if your greenhouse is large.

  2. Regular Cleaning: To prevent the growth of mold, bacteria, or algae, clean the humidifier regularly according to the manufacturer's instructions. This usually involves emptying and rinsing the water tank, cleaning filters or wicks, and wiping down the internal components. Some humidifiers have parts that are dishwasher safe, which can make cleaning easier.

  3. Use Distilled or Filtered Water: Tap water often contains minerals that can build up in the humidifier over time, potentially damaging the unit or creating "white dust" in the greenhouse. Using distilled or filtered water can help prevent these issues.

  4. Monitor Humidity Levels: Too much humidity can be as harmful as too little. Use a hygrometer to monitor the humidity levels in your greenhouse and adjust the humidifier settings accordingly. Most plants prefer a relative humidity between 50-70%, but specific needs can vary.

  5. Maintenance During Off-Season: If you won't use the humidifier for an extended period, clean it thoroughly and dry all components before storage. This prevents the growth of mold or bacteria in the unit.

  6. Regular Inspections: Inspect your humidifier for any signs of wear, damage, or malfunctions. Catching potential problems early can help prevent costly repairs or damage to your plants.

These tips can optimize your greenhouse humidifier's performance, enhance your plants' health and growth, and extend the unit's lifespan.


In conclusion, the right greenhouse humidifier can significantly improve the health and vigor of your plants by maintaining optimal humidity levels. Whether growing delicate tropical species or robust vegetables, a humidifier can prevent common problems associated with low humidity, like wilting and slowed growth. However, choosing the suitable model that fits your greenhouse's size and caters to your plants' needs is essential. Also, remember that proper use and regular maintenance will ensure your humidifier runs efficiently for a long time, giving your plants the best possible growing environment. Explore options, consider your unique needs and budget, and transform your greenhouse into a thriving, verdant space.