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  • Naomi Stephens | Permaculture Designer

The Impact of Humidity on Plant Growth and How to Regulate it Naturally

Updated: Mar 6

If you like to have plants around the house, then you know that keeping the humidity at a reasonable level is essential. If there is too much humidity, your plants will rot. If there is too little humidity, they will wither and die. That's why having a humidistat or humidity checker is essential to help you monitor the humidity levels.


In this blog post, I'll discuss what humidity checkers are, why you need one, and what to look for when choosing one. We'll also recommend some of the best humidity checkers on the market.




1. What is a Humidity Checker?

A humidity checker, also known as a hygrometer, is a tool used to measure the moisture level in the air. For indoor gardening, monitoring humidity levels is essential for promoting healthy plant growth. Plants transpire through their leaves and release water vapor into the air, making humidity a vital factor for regulating moisture levels for the plants.


Too much or too little humidity can cause issues such as wilting and browning leaves. Gardeners can use a hygrometer to monitor humidity levels and adjust moisture-adding techniques such as misting or pebble trays to ensure optimal plant conditions. Overall, a humidity checker is valuable for any indoor gardener looking to provide optimal plant care.


2. Why Do You Need a Humidity Checker?


Whether you're an indoor plant enthusiast or a green-thumbed gardener, paying attention to the humidity levels in your surroundings is essential. Too much or too little moisture in the air can have disastrous effects on plants - causing wilting, yellowing leaves, or even fungal diseases.


Each plant type has its preferred range of humidity, and environmental factors like temperature and light exposure can also affect these needs. That's where a humidity checker is handy - it allows you to monitor and maintain the perfect plant balance. In addition to promoting their health and well-being, keeping your plants in optimum conditions can result in bigger yields and more beautiful blooms.


3. How to choose the right level of humidity for your plants


Choosing the right humidity level for your plants can be tricky. So, how do you determine the perfect humidity level for a specific plant?


First, take note of where the plant originates from. Plants from tropical regions will likely thrive in higher humidity levels, while desert plants may prefer drier conditions.


Next, observe your plant's reaction to its surroundings. Are the leaves wilting or drooping? This could indicate that it needs more moisture.


Do they appear crispy or discolored? This could mean there is too much moisture in the air. Adjust accordingly, and you'll soon have a happy, healthy plant on your hands.



4. How is humidity measured?

Humidity levels are measured in two ways: absolute and relative. Absolute humidity is the actual amount of moisture in the air, while relative humidity measures how much moisture the air holds compared to its maximum capacity.

What does RH mean?

RH stands for Relative Humidity. As explained, relative humidity is the amount of moisture in the air compared to the amount of moisture the air can hold at a specific temperature. The higher the relative humidity, the more moisture in the air. For example, if the air holds all the moisture it can at a specific temperature, the relative humidity would be 100%. If there were half as much moisture in the air as it could hold at that temperature, then the relative humidity would be 50%.


Most plants' ideal relative humidity is between 40% and 60%. This means the air is holding 40-60% of the moisture it could hold at that temperature.


5. What are some ways to increase humidity?



There are a few ways to increase humidity:


  • Place a bowl or tray of water near your plants

  • Use a humidifier

  • Group your plants together

  • Cover your plants with plastic (make sure there are holes for ventilation)

  • Grow tropical plants


Place a bowl or tray of water near your plants.


Placing a bowl or tray of water near your plants helps to increase humidity because as the water evaporates, it adds moisture to the air. This helps to keep the air around your plants more humid and can help them grow better. It is beneficial for houseplants that need extra humidity to thrive.



Use a humidifier


Using a humidifier helps to increase the humidity in a room by releasing water vapor into the air. The unit uses an internal fan to blow air through a dampened filter or wick, which captures and holds water. This allows the fan to draw in dry air and blow it out as moist, humidified air.

Group your plants together

Grouping plants helps to increase humidity because their transpiration rate rises when they are nearby.


As plants transpire, they release water vapor into the air, which increases the amount of moisture in the environment and thus contributes to higher relative humidity. This can be especially beneficial for tropical plants that thrive in humid environments.


Cover your plants with plastic (make sure there are holes for ventilation)

Covering plants with plastic helps to increase humidity by trapping moisture around the leaves and preventing them from evaporating into the air.


This creates a warm, humid environment ideal for many plants that thrive in high-humid conditions.


The holes for ventilation ensure that the air does not become too stagnant and create an excess of humidity that is detrimental to plant health.


Grow tropical plants

Growing tropical plants can help increase humidity by releasing moisture through their leaves through transpiration. This helps create a more humid environment in the surrounding area, which benefits other tropical plants and organisms.


Examples of tropical plants that can be grown easily indoors to increase humidity include:


- Monstera deliciosa (Swiss Cheese Plant),

- Calathea orbifold (Rattlesnake Plant),

- Philodendron scandens myocardium (Heartleaf Philodendron),

- Spathiphyllum (Peace Lily),

- Ferns,

- Guzmania lingulata (Scarlet Star Bromeliad)

- Zamioculcas zamiifolia (Zanzibar Gem).



6. What are ways to decrease humidity?


There are a few ways to decrease humidity:

  • Place your plants in an airy room

  • Use a dehumidifier

  • Make sure plants are not over-watered

  • Grow desert plants


Placing Plants in an Airy Room


Placing plants in an airy room naturally reduces humidity because the air circulation helps evaporate some of the water released by the plants through transpiration. This process not only cools down the air but also helps reduce humidity levels in the space.


Use a Dehumidifier


A dehumidifier helps to reduce humidity by removing moisture from the air. It works by using a fan to draw air over a cold evaporator coil, which causes the moisture in the air to condense and drip into a collection tray. The fan then blows warm, dryer air back into the room.


Making Sure Plants Are Not Overwatered


Ensuring plants are not overwatered naturally reduces humidity because excess water creates moisture, leading to higher humidity levels. To ensure plants are not over-watered, check the soil before watering – if it is already moist, wait until it is dry before adding more water.


Additionally, when watering plants, avoid using too much water and ensure that all excess water drains away from the plant to prevent damp soil and root rot. Finally, pay attention to the climate and season – tropical plants require less water during winter than in summer.


Growing Desert Plants


Growing desert plants naturally reduces humidity because many adapt to survive in hot and dry climates. These plants have developed mechanisms that help them conserve water and minimize transpiration, which helps keep the air around them drier.


For example, some cactus species have thick waxy stems that reduce evaporation, while other species have specialized hairs on their leaves that can help trap and hold moisture. Additionally, some desert plants have deep root systems, allowing them to access moisture below the soil's surface. This can further reduce the amount of water vapor in the ground.


Examples of desert plants that can be grown easily indoors to prevent humidity include:


- Aloe Vera

- Ponytail Palm

- Burro's Tail

- Jade Plant

- Cactus varieties (e.g., Christmas Cactus, Easter Cactus, Hybrid Cacti)

- Snake Plant

- Spider Plant

- Zebra Plant


7. How to use a humidity checker





Using a humidity checker is simple - place it in the area you want to monitor and wait for the reading.


Most units will give you an instant measurement, but some may require you to wait a few minutes for an accurate reading. Once you have your number, compare it to the ideal range for your plants (you can find this information online or in gardening books).


If the level is too high or too low, take steps to adjust it accordingly. For example, if the air is too dry, you can try misting your plants or placing a water bowl near them. On the other hand, if the air is too humid, you can try opening a window or using a fan to circulate the air.

8. What to look for when choosing a humidity checker


When choosing a humidity checker, there are several factors you'll want to keep in mind.


First, consider the type of display you prefer. Some models feature digital readouts, while others have analog displays. If you're looking for more precision, opt for a digital model. However, analog models are often easier to read at a glance.


Next, decide what range of humidity levels you need to measure. Most home humidifiers will suffice for general indoor gardening purposes. Still, if you're growing plants that require specific conditions (such as tropical orchids), you may need a unit with a more sensitive range.


Finally, think about the size of the unit and where you'll be placing it. If space is limited, look for a compact model that can be placed on a windowsill or shelf.


9. Some of the best humidity checkers on the market


Many great options exist if you're in the market for a humidity checker. However, I recommend a few:



Doqaus Digital Hygrometer


If you are looking for the best, most affordable humidifier, this one is it. The features, reliability, and positive reviews make it the well-rounded option for everything you need.


Features:

  • Refreshes every 5 seconds

  • In-built thermometer

  • Humidity is accurate to +/-5% humidity

  • The display shows whether the moisture is Dry, Comfort, or Wet

  • There are multiple ways to place this in your home, i.e., hanging hole, magnet, or stand.

  • Batteries are already included.




At the time of writing, this costs $9.39




Govee Indoor Hygrometer


If you want more functionality, convenience, and data to optimize your growth, go for the Govee Indoor Hygrometer. It comes with two humidity checkers, a bonus for a large growing area, or the ability to use one for different purposes. Humidity checkers are not just good for plants; they have other uses; for example, I have one by my plants and in the room where my baby sleeps.


The meter can connect to your phone to check your humidity while on the go. It can also notify you about the moisture, so you don't have to check it actively. Let's say you want to analyze and optimize your growth; this will record and have access to up to 2 years' worth of data. This is a feature I love, particularly for small greenhouses, as the humidity can change a lot.


Features

  • 2 seconds refresh

  • Two humidity checkers

  • The app includes notifications

  • Ability to save data

  • Minimum and max gauge

  • Thermometer



At the time of writing, this costs $26.00




No matter which model you choose, a humidity checker is a valuable tool to help you keep your plants healthy and happy.


Thank you for reading. If you found this article helpful and want to learn more, check out the rest of our blog for more helpful tips on garden maintenance and optimization. Happy Growing!


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