6 houseplant humidity mistakes – and how to fix them like a pro

Humidity plays a key role in plant growth, affecting everything from moisture retention to nutrient absorption, so it's no surprise that getting humidity levels wrong can harm your houseplants.

Too little humidity can cause leaves to dry out and crisp at the edges, while too much can create the perfect environment for mold, mildew, and pests. Finding the best humidity level in your home is key to keeping your plants thriving. Some species require higher humidity, while others prefer drier conditions.

Ultimately, it comes down to understanding your plants' specific needs to avoid an unhealthy balance. To help you achieve this, we asked experts for their best advice on swerving the most common indoor plant mistakes when it comes to humidity.

1. Not checking your plants' ideal humidity levels

Just as it’s important to understand a plant’s ideal temperature, water, light, soil, and fertilizer conditions for healthy growth, it’s equally essential to learn about the optimal humidity levels for your plant. Without the right humidity levels in your home, plants may struggle to thrive, leading to slowed growth, browning leaves, or even stress-related damage.

In general, tropical plants thrive in humid environments between 60% and 80%, as they naturally grow in humid environments like rainforests. Desert plants, on the other hand, are adapted to dry, arid conditions and prefer much lower humidity, usually between 10% and 30%. Succulents and cacti, which are often found in semi-arid climates, also prefer lower humidity, ranging from 20% to 40% is ideal for them.

For plants native to forests with seasonal humidity changes, a moderate level of 40% to 60% humidity is usually best. These plants can usually adapt to varying humidity but still require some consistency to thrive. Plants like orchids and ferns which thrive in humid environments often prefer humidity levels above 50%, with many types benefiting from a range of 60% to 80%.

To monitor humidity levels accurately, consider placing a hygrometer – such as this ThermoPro from Amazon – near your plants, as this will help you ensure they are in the right environment for healthy growth, and adjust them accordingly if not.

2. Relying on misting to increase humidity

'I don’t want to outright call it a mistake, but misting is a common misconception that doesn’t do nearly as much for your plant as you might think it does,' says Justin Hancock, horticulturist at Costa Farms. 'Misting does add a very short-term increase in humidification, but once it evaporates, the moisture is dispersed around the room, eliminating the humidification effect.'

While many of us often turn to misting to raise humidity levels for houseplants struggling with low humidity in the home, it can sometimes do more harm than good. The temporary surface moisture can create ideal conditions for fungal issues, especially in spaces with poor air circulation.

Rather than misting, consider using a room humidifier or grouping plants together to create a stable microclimate with naturally higher humidity. Humidifiers, especially those with built-in hygrometers, such as this humidifier from Walmart, are a highly effective way to increase humidity for indoor plants, allowing you to monitor and adjust humidity where necessary to keep plants happy.

Justin Hancock

Justin Hancock is a Costa Farms horticulturist with over 25 years in the industry. A plant enthusiast and educator, he has a degree in horticultural science and has worked in garden centers and botanical gardens, as a garden designer, and in garden publishing (including at Better Homes and Gardens). He has experience gardening across the country, from Minnesota to Oregon to Miami. Justin is also co-host of the Costa Farms podcast Plant Rx.

3. Not utilizing pebble trays properly

While pebble trays filled with water placed beneath plants are often recommended for increasing humidity, they don’t significantly change humidity levels, warns horticulturist Gail Pabst , at the National Garden Bureau.

‘This method would be effective if the humidified air rose directly to the plant and stayed concentrated around it, but it does not,’ explains Gail. Instead, the moisture disperses throughout the entire room rather than staying concentrated around the plant.

This doesn’t mean pebble trays can’t be used to increase humidity, however, it’s just about how you use them. Placing plants in a smaller, enclosed space like a glass cabinet or terrarium – such as this Ferrisland glass plant terrarium from Amazon – helps retain moisture, making the trays more effective.

Gail Pabst

Gail is a passionate horticulturist with over 25 years' experience in the industry. She is an avid home gardener too and loves to try out the newest varieties and techniques. Gail's work with the National Garden Bureau and the All-America Selection has helped her to continue their mission of inspiring and teaching gardening with others.

4. Placing plants near sources of inconsistent humidity

Placing plants in naturally humid spaces, such as bathrooms, kitchens, or laundry rooms, is often recommended for moisture-loving species. Certain houseplants can help to absorb excess moisture and reduce condensation, making them great choices for these spaces.

However, the features that create high humidity in these spaces – showers, stoves, dishwashers, and washing machines – also lead to fluctuations, making it challenging for plants to thrive. This can stress certain houseplants, leading to issues like browning leaves or fungal growth.

To successfully grow plants in a bathroom, kitchen, or laundry room, choose resilient, humidity-loving varieties like ferns or calatheas, and monitor their condition to ensure they adapt well to the environment.

5. Overwatering to increase humidity

It’s a common myth that watering houseplants more frequently to keep the soil moist will help increase humidity. In reality, this approach is more likely to cause root rot than raise humidity levels. Humidity comes from moisture in the air, not from overly damp soil.

The best approach is to water your plants according to their specific needs and boost humidity using reliable methods, such as a humidifier, using a humidity dome for tropical species, or grouping plants together.

Justin Hancock explains: 'Grouping plants together can create humidity zones because plants release moisture through their leaves. If you have a cluster of plants, the plants in the center will benefit most from being surrounded by other leaves.'

These controlled techniques can provide consistent moisture without risking your plants' health.

6. Placing plants near heating or AC vents

Just as placing houseplants in spaces with inconsistent humidity can be problematic, positioning them near heat or air conditioning vents can also be harmful to your beloved plants.

These can create dry air currents that strip humidity and moisture from plants, leading to stress. Even if you’re using a humidifier, the constant airflow can counteract its effects by drying out the leaves.

To prevent this, be sure to keep plants away from direct air vents and drafty areas, such as windows.

FAQs

What are some telltale signs that a plant isn’t getting enough humidity?

'Brown, crispy leaf tips or edges are one of the most common signs of low humidity,' explains Justin Hancock.

'It’s important to keep in mind that there’s a relationship between humidity and moisture in that your plants may hold up okay in lower-humidity conditions if they’re adequately watered; but if they dry out in that same amount of humidity, then they can suffer. It’s also worth noting that the brown, crispy leaf edges from low humidity can be caused by exposure to drafts or other causes, as well as humidity.'

How can too much humidity negatively affect houseplants?

'Too much humidity is more likely to negatively impact your house than your plant,' Justin says. 'High-humidity conditions can encourage fungal growth, and if your plants are stressed, it can make them more likely to be attacked by fungal diseases.

'Good airflow and lots of light can help prevent this. In really high-humidity conditions, especially in lower light levels and lower airflow, you may see fungal or mold growth on the soil, pot, etc.

'It’s important to keep in mind that these fungi aren’t pathogens – they don’t attack the plant if they’re on the soil, pot, your wall, etc.'

So remember, the biggest houseplant humidity mistake is to ignore each plant's specific needs. To increase humidity, use controlled methods such as humidifiers, group plants together to create a humid microclimate, or place pebble trays inside terrariums for better moisture retention. To safely lower humidity, improve airflow and avoid overwatering.

Being a better plant parent involves paying close attention to your plant’s ideal environment, creating the right conditions, and monitoring for signs of stress. Using a hygrometer to monitor humidity and making adjustments accordingly will help keep your plants at their ideal moisture levels, ensuring they stay healthy and thriving.