Philodendrons are popular houseplants because of both their beauty and their gentle tolerance of conditions that are not quite ideal. In terms of humidity, these plants will tolerate a wide range of different moisture levels but will thrive if you can keep them in their ideal conditions.
This is surprisingly easy to do if you make some minor changes in the way that you care for your plants. Most houses are kept at humidity levels that fall below perfect conditions for the Philodendron, but it is perfectly possible to raise the moisture level within the vicinity of your plants.
Philodendrons will tolerate a wide range of humidity levels. But as you will see, it is also quite easy to raise or lower the humidity so that you are growing your plants under perfect conditions. This will result in your Philodendron performing at its peak and producing more flowers and healthier foliage.
How does Humidity Affect the Philodendron?
Under perfect humidity conditions, the Philodendron absorbs nutrients by taking them up in a dissolved form through the roots and then passing out the excess moisture via pore-like cavities, called stomata on the underside of the leaves. If this process is interrupted because of either too much humidity or too little humidity it will affect the overall health of the plant.
If the humidity levels are too low, your plant will start to exhibit signs of stress. The transpiration rate increases and the plant struggles to absorb enough nutrients. The first thing you are likely to notice will be brown leaf tips followed by yellowing of the leaf margins. As the problem becomes more established, both the flowers and the leaves will start to shrivel and dry.
In cases where the humidity level becomes too high, respiration is reduced as the plant holds too much moisture. What you will start to see is a gray mold develop on the leaves and later on the flowers themselves. Both the leaves and stems will eventually rot if the problem is not addressed.
How Much Humidity Does the Philodendron Need?
These plants come from tropical rainforest-type environments and so they like quite high levels of humidity. Between 65 and 80 percent is a good range to aim for, though that could be allowed to drop to 55 percent overnight.
Most homes have humidity levels that are around 40 to 60 percent. The plants will tolerate this, but I like to keep my plants closer to their ideal natural range so that they reward me with maximum growth and flower production.
Because of this quite a dramatic difference between what the plant favors in terms of humidity. And what the homeowner favors, it is easy to see why there is potential for problems to occur.
How to Measure Humidity in Your Home?
I must admit that for many years I never really checked the exact humidity in my house. My plants seemed to be coping well, and so I simply assumed that I must be getting the humidity more or less right.
As my plant collection began to grow and become more of an important aspect of my décor, I realized that it might be wise to start taking a more scientific approach to this subject. It also dawned on me that I was now quite heavily invested in my houseplants and so it made sense to ensure their well-being.
Today, it is possible to purchase digital hygrometers for very little money. These small and inexpensive devices measure both temperature and humidity with a high degree of accuracy.
Most suppliers suggest that they will be out by only 1 to 3 percent. Because they are so cheap, it is easy for me to keep several of them dotted around the plants that make up my indoor garden.
How to Use a Humidity Meter?
Digital hygrometers are really easy to use because all you need to do is to turn them on. It is worth noting that it does take around two hours for them to adjust to their environment and start giving accurate readings. I place several among my plants and one elsewhere in the room.
This gives me an overall picture of the humidity around the plants, as well as a general overview of the humidity in the room itself.
If there is a big difference between where the plants are growing and the remainder of the room, I know that I will soon need to take appropriate action. Low humidity in most of the room, for example, will soon translate to lower humidity near the plants. The two environments are not totally separate from one another.
Helping Philodendron Deal with High Humidity
If you see from your hygrometer that humidity is becoming too high, then you will need to take steps that lower the moisture level in the air. If you don’t have a hygrometer and you start to see signs of mold either on the plant or on the top of the potting soil, then you should follow these procedures as well.
Avoid Excess Watering
Much of the moisture in the air around your philodendron will be derived from moisture in the potting soil and that given off by the plant through the process of transpiration.
Allowing your philodendron to dry out slightly between each watering will reduce this excess dramatically. Your Philodendron will also thank you for this reduction in excess water surrounding its roots.
You can get a fairly accurate measure of how wet the potting soil is just by poking your finger into the top two inches. Don’t water unless you can feel that the soil is dry to that depth.
There is no exact time schedule for this to take place as it will vary because of temperature, speed of transpiration, and water retention of the soil. Checking regularly is the only reliable measure.
Improve Indoor Circulation
If the air in the room becomes stagnant, that provides ideal conditions for a build-up in the humidity level. This is not only bad for the philodendron, it is not terribly healthy for you either. The problem is easily rectified simply by opening a window or two for a few hours each day.
The increased circulation should soon lower the humidity in the room. Also, having doors at each end of the room open will allow for air movement to take place more freely.
Place Your Plant Near to a Window
The air around the window is generally the air that is most likely to be kept moving and therefore is less prone to becoming overly humid. Philodendrons don’t like direct sunlight so choose a windowsill that offers bright light but not too much sun or your plant will get burned.
When the outside temperatures are warm, opening the window for just a few minutes will lower humidity around the Philodendron.
Choose an Appropriate Potting Soil
At first, the idea that potting soil could increase humidity seems a little far-fetched. When you think about it, however, you realize that damp potting soil is probably one of the most water retentive areas in your room.
Philodendrons don’t like to have their feet wet, and so even if humidity is not too high, you are well-advised to use a free-draining potting medium.
By mixing a good houseplant potting soil with fifty percent perlite. The water will drain away quickly while still providing a moist enough environment for your precious plant. Remember that high levels of things such as peat or coconut fiber will increase the moisture retention of potting soil.
By providing the right amount of light, you will decrease humidity, speed transpiration and increase plant growth. Ideally, Philodendrons like to have about eight hours of bright light each day.
In some areas, there will be a perfectly adequate supply of natural light. In darker rooms or places with long harsh winters, these requirements are not always met. It is here that grow lights will really come into their own.
Choosing Grow Lights
Ordinary domestic lights simply do not provide a broad enough spectrum of light to cover all of the requirements for healthy plant growth. Unlike humans, plants require light to produce energy.
philodendrons that lack light will grow less effectively, transpire less efficiently, and therefore encourage a build-up of humidity. Good lights may well address this problem.
- Grow lights need to be on for eight to ten hours per day.
- Choose a low energy light.
- LED white lights are ideal.
- Place them directly above your plants.
- Don’t allow the lights to touch the foliage as this may burn the leaves.
- Use them in combination with a timer for maximum effectiveness.
Finally, grow lights are not always a necessity. It may well be that your Philodendrons receive sufficient natural light or that you only need to consider their use over the shorter winter days.
Signs Your Philodendron Needs More Humidity
While the risk of excess humidity is real, in your home, it is far more likely that low humidity will become a bigger problem than high humidity.
That is because most of us live in homes with humidity levels that linger between forty and sixty percent. Most Philodendrons will tolerate this lower than ideal moisture level in the air but will still not thrive as well as they could do.
There are a couple of reasons that you may want to provide higher levels of humidity. The first is that plant performance will improve with higher humidity levels. The second is that lower humidity brings with it certain health risks such as brown leaf tips, crisp leaves, and yellowing of the leaf margins.
If your plant is not displaying any of these symptoms, you can carry on growing your plants at the humidity level you are already providing.
Methods of Improving Low Humidity
Grouping Plants Together
This is a simple but effective way to raise the humidity in the vicinity of that plant group or island. Their combined respiration releases moisture into the air and that creates a microclimate that is less dry.
Another really easy trick is to stand your Philodendron on a gravel tray. Fill a tray or plant saucer with gravel or pebbles and then pour in enough water to nearly cover the material you have chosen.
When you stand your potted plant back in the saucer it is sitting above, but not in, the water. As the water evaporates, the humidity is raised but without the risk of the root system becoming waterlogged.
These devices increase the humidity in the air. You have two basic options. One heats the water and releases it as steam, and the other agitates the water and releases it as mist.
By placing them in the vicinity of your Philodendron you can adjust the humidity level to the exact requirement. Not always the best option if you only have one or two plants, that may change if you decide to build up your collection.
These mini greenhouses may be quite useful, especially if you have a large room and you are having trouble regulating the humidity conditions. Essentially, all they are are are mini-greenhouses that you can keep in the house. They can be made from framed glass or clear plastic and they normally hold up to a half dozen plants.
The smaller environment that they create makes it far easier to provide ideal growing conditions in terms of both temperature and humidity.
For decades, the accepted method of raising humidity has always been to give the leaves of the plant a light spray of water with a squeegee bottle. The moisture would settle on the leaves and therefore the humidity level would increase as it evaporated.
Recent studies have somewhat changed the way we look at this practice. What the new studies suggest is that the humidity is only raised very briefly before descending to its original level once again. In the process, the wet leaves become more vulnerable to things such as mold and rot that one would normally associate with excess humidity.
Philodendrons are happiest at a room temperature of between 55 and 90 °F (12 – 32°C). Humidity levels are higher when the air temperature is higher because the warmer air can hold greater quantities of water. This rule is not totally fixed. For example, hot dry regions such as deserts have drier air because there is no water for the hot air to absorb.
In your home, higher temperatures can mean higher humidity levels, especially if there is moisture to be absorbed such as from wet potting soil, your fish tank, or water build up in the plant saucers. You need to be aware of this and check your moisture meters regularly.
Conversely, during the cold winter months, we often heat the room with fires and central heating. This can create a dry but warm environment that will have low humidity. These plants are not adapted to these changes and you will need to monitor your humidity levels throughout the year.
Humidity Requirement of Philodendron Varieties
There are over three hundred different types of Philodendron. Most of the common ones conform to the requirements that I have mentioned here when it comes to humidity, temperature, and lighting requirements. You need to be aware that some of the more exotic varieties can be a lot more demanding in terms of what they need in order to survive.
I suggest that you start off growing the more widely cultivated varieties, of which there are many, and that only once you really understand these plants do you experiment with the more complicated specimens. Unusual varieties tend to be a great deal more expensive because they are so much more demanding in their growing requirements.
An all-around easy plant that is very tolerant and offers a wide range of varieties to choose from. These are the most important things to take into account in terms of humidity
- The ideal humidity range lies between 65 and 80 percent.
- Use a hygrometer to best monitor humidity.
- Establish a watering routine that allows the plant to dry out between each watering.
- Use a free-draining potting medium.
- Know what signs to look out for in terms of both high and low humidity.
- Take local weather into account for both light and humidity level.
- Consider equipment such as grow lights, humidifiers, and indoor greenhouses.
- Choose a common variety to begin your Philodendron adventure.
Remember that the closer you are able to replicate the plant’s natural conditions, the happier your Philodendron will be. In return, it will grow faster, produce lusher foliage, more flowers and be more resistant to pests and diseases.