Adding Humidity to Benefit Houseplants

An important consideration when it comes to proper care of houseplants is the humidity level inside the home. Many popular houseplants are native to tropical regions where relative humidity, the amount of moisture contained in the air, is high. Yet, in our homes, humidity levels can be quite low due to air conditioning in the summer and heat in the winter, which results in dry air. It can cause plants to struggle. 

What is transpiration

Plants use a process known as transpiration to move water and nutrients from their roots to the stems and leaves. When that water reaches the leaves, it is released into the atmosphere through tiny holes in the leaf surface. When the humidity levels are high, that slows the water loss, and the plants will not need as much water. But when humidity levels are low, temperatures are high, and the air is dry, the plant will lose more water through transpiration. It can cause their edges and tips to become brown and unsightly. 

7 tips for increasing humidity for indoor plants

1. Consider plant choice

Some plants require more humidity than others. For example, cacti and succulents handle low humidity well. Nebraska Extension shares others: cast iron plant (Aspidistra sp.), Chinese evergreen (Aglaonema sp.), Philodendrons and Draceanas. On the other hand, most ferns, Rex begonias, and prayer plants (Maranta spp.) require high humidity.

2. Avoid placing plants near heat sources and ducts

Winter heat sources can dry out plants quickly but so can summer air conditioning. Move plants to a location where they don’t have to contend with air fluctuations and drying conditions caused by heating and cooling air movement.

3. Place plants in high humdity areas of your home

Places in the home that typically have higher humidity levels are the bathroom, due to baths and showers, and the kitchen, due to dishwashing and some types of cooking. These rooms may be reasonable options, depending on your space.

4. Add a humidifier

If your home environment is dry, a humidifier can help by adding moisture into the air. This can be beneficial to both humans and plants as many homes have a lower humidity level than the 30 to 50 percent that is recommended for humans. When you consider that plants need between 70 and 80 percent humidity, it’s easy to understand why they may struggle in some homes. While whole-home humidifiers work in conjunction with your HVAC system, there are small, portable devices available. When using these, it’s best to set them near your plants so they can receive the benefits. 

5. Group your plants

When plants are grouped or placed together, they create their own microclimate that can increase the relative humidity. Grouping them is also helpful if you are using a small humidifier in one room.

6. Create a pebble humidty tray

One practice that some use is a pebble humidity tray. Simply fill a shallow pan or tray with an inch or two of pebbles, lava rocks, or small stones. Place the plant container on the stones and then add water to the tray. It’s important to keep the water below the base of the plant container. The idea is for the plants to benefit from the water evaporating from the tray, which will increase the humidity. If the plant container sits in water, it can uptake the water and result in constantly wet soil and root rot. 

7. Trap the moisture with a glass jar covering

This is a concept like terrariums where moisture is trapped inside a glass jar. A cloche or similar covering is an option that is practical with only a few small plants. 

Should I mist my plants

Many horticulturists caution against misting plants, which would need to be employed often to even approach raising the humidity level. So, in addition to not changing the humidity level, keeping plant foliage wet can introduce various diseases. Just as with outdoor plants, if you mist indoor plants, do so early in the day so the foliage can dry before evening.

Most houseplants grow well in warm environments, with temperatures between 65- and 75-degrees F. Give them plenty of light, water when needed but don’t overwater, and pay attention to humidity levels, and you’ll be on your way to having happy, healthy plants. 

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