Humidity is one of the environmental factors that we indoor gardeners often overlook when it comes to caring for our plants. Pothos are tropical plants, and although they will tolerate quite low levels of humidity.
They will achieve their maximum potential if you provide them with humidity levels that most closely emulate their natural environment.
Pothos plants will tolerate a wide range of humidity levels and anything that falls out of this can usually be rectified by making minor changes such as grouping plants and using gravel trays.
In this article, we look at some easy ways to do just that, as well as the signs and symptoms your plant will exhibit when humidity levels are not ideal.
How Does Humidity Effect Your Pothos?
What incorrect humidity does is that it interferes with the transpiration levels of your pothos. Nutrient-carrying water is absorbed by the roots and then excess water is released through small pores, called stomata, on the underside of the leaves after the nutrients have been used by the plant.
If the plant is lacking humidity, it panics and doesn’t open those pores fully. Transpiration slows down as a result, and the overall well-being of the plant begins to deteriorate.
Because the Pothos is a really robust plant, it may not show any immediate detrimental signs, but overall performance will be inhibited.
By bringing the humidity levels within those required by the Pothos, you will discover that it starts to turn into a much more healthy and handsome plant.
If humidity is overly high, your plant will become susceptible to mold and fungal diseases. These can cause wet brown spots and flaccid leaves and stems. In more extreme instances, it can result in root rot which, if left untreated may prove fatal.
How Much Humidity Does your Pothos Need?
Humidity is basically the amount of water vapor that the air can hold. The higher the temperature, the more moisture there will be in the air.
It’s not quite as simple as that because if the environment is dry and hot, humidity may still be low, as in desert regions. This is because there needs to be a combination of both warmth and moisture for humidity to form.
If you heat your house and there is no moisture available, the air will become drier and the humidity level will go down. If there is moisture around, the warm air will be able to absorb it and the humidity will go up. What you are trying to do is to maintain moisture levels at a percentage that most suits your house plants.
This probably sounds very complicated, but as you are about to see, simply by using some simple tricks, and measuring the humidity regularly, you will be able to keep it within the range that you want it to remain at.
Because your Pothos comes from warm tropical parts of the world it likes high humidity and will be happiest at humidity levels of between 50 and 70 percent. It will even sustain humidity as high as eighty-five percent.
How Do You Measure Humidity in your Home?
The only accurate way to measure relative air humidity is with the use of a hydrometer. Luckily, these little instruments are inexpensive and easy to use. These days, they all tend to be digital and when turned on, will often provide you with both a humidity reading and room temperature.
The only thing you need to remember is to make sure that you are taking your reading in the vicinity of the plant as different parts of a room may well have different humidity levels. The ideal room temperature for a Pothos lies between 65 and 85°F (18-30°C)
If you have a lot of house plants, it is not a bad idea to have two or three different hydrometers dotted about your indoor garden. This will enable you to most effectively measure humidity levels in all areas and react accordingly.
The hydrometer is only as effective as the number of times you monitor it. Remind yourself that humidity is altered by a number of factors such as weather, heating, and soil conditions. Only by reading the hydrometer often you will have an accurate overall picture.
Helping Your Pothos to Deal with High Humidity
Now that we know how to measure humidity levels and how it affects your pothos, we need to start looking at ways to deal with any problems where humidity falls outside of the requisite levels. We will start off by looking at excess humidity.
The first place to start is to avoid overwatering your plant. If you are watering too heavily, there will be a moisture build-up in the potting soil and some of this water will evaporate into the surrounding atmosphere.
Naturally, this will result in increased humidity levels and your hydrometer will quickly let you know if humidity has become too high.
The easiest way to overcome this problem is to adopt the correct watering regime. These plants can take low water levels so allow them to dry out between each watering and do not water again until the top two inches of the soil have become dry.
I find the easiest and most reliable method of checking this, is to poke my finger into the soil to the depth of my second knuckle.
If the soil feels dry then I know it is time to water. Soak your Pothos thoroughly and then allow all water to drain away before placing it back in its plant saucer and returning it to its original position.
The amount of moisture retained by different types of potting soil can vary immensely. Ideally, you should plant your Pothos into a quality house plant compost that offers good drainage.
If there is too much water-retentive material, such as peat or coconut husk, in the potting mix it will retain much more moisture. In a high humidity situation, this is not desirable.
You can increase drainage by mixing twenty to thirty percent perlite or grit into the potting mix you use before planting your Pothos.
These plants do not like to be surrounded by too much growing medium and will be happy with quite a tight spot. When you finally do need to replant into a bigger pot, do so using a pot that is only one or two inches larger in diameter than the one that the pot just came out of.
Lack of air circulation around your Pothos is another reason that there might be an excess build-up in the humidity levels.
Simply by opening some doors or windows, you might well find that you can bring that humidity back to within acceptable levels as the air starts to pass through the room more freely.
On the subject of windows, providing your plant is not in prolonged direct sunlight, it will benefit from growing on a windowsill.
Humidity level tends to be lower and the extra lighting will also suit your Pothos. Providing it is not too cold outside, you can further increase airflow by opening the window for an hour or two during the middle of the day.
Finally, another way to improve growing conditions and reduce humidity is through the use of grow lights. This artificial lighting replicates sunlight, increases evaporation, and extends the growing time each day. They are particularly useful if you growing house plants in northerly regions where the days are shorter.
There was a time when grow lights were so expensive that they were beyond the reach of most domestic house plant growers. Today, because of changes in technology, the price has come down dramatically and the indoor gardener is now exposed to a wide range of different lighting options.
This requires that you do some research in order to find the lights that are most appropriate to your conditions. I would recommend choosing lights that you can direct at your plant rather than having a full 360° spread.
Avoid the temptation to leave lights on all day in the hope that the extra hours of daylight will give you larger, better-looking plants. All plants need a rest period when they are cloaked in darkness to perform at their best. (A bit like gardeners really.)
Signs Your Pothos Needs More Humidity
Low humidity is a far more common problem than excess humidity is when it comes to house plants in the US and Europe. This is because so many of our favorite houseplants come from humid tropical areas.
Excess humidity is more often found in glass houses and commercial greenhouses than it is in the average domestic home though if you are growing your Pothos in a bathroom this might not apply.
Part of the reason that our homes are so low in humidity that we heat them and seal the air in with double glazing.
If your Pothos is suffering from too little humidity, these are the signs to look out for
- Brown leaf tips
- Leaf margins that become crisp and dry
- Wilting and general drooping of the leaves
- Finally, the leaves might start to turn yellow and drop off
These symptoms are not exclusive to a lack of humidity, but if you make use of a hydrometer it will quickly confirm your diagnosis if you experience any of them.
Remember that these plants are extremely forgiving, and even if they are not showing any of the above symptoms, lack of humidity may be hindering them from achieving maximum performance.
How to Increase Humidity
There are several options available to you when it comes to raising the humidity levels in the area of your plants. They range from low tech to slightly more high tech.
I would suggest starting with some of the most basic methods and then getting more complicated only if you have not achieved the results that you are after.
By placing several plants in a group, you will discover that the humidity level in the vicinity of those plants goes up. This is because the combined transpiration of the plants automatically increases humidity in their vicinity and creates a mini-microclimate. This is a tried and trusted method and is normally my first port of call when faced with low humidity problems.
In order for the humidity to go up, there needs to be a water or moisture source from which the air can draw. You have several options here as the air is no fussy where it draws moisture from.
Aquariums and bowls of water will do the job, but an even easier method is the gravel tray. Here a tray or even just a plant saucer is filled with gravel and the plant pot is placed on top. The tray can not be topped up to the level of the top of the gravel with water. This will allow evaporation to take place right in the vicinity of your Pothos plant.
These appliances are designed to increase the ambient moisture level in the air. They are sold at many garden centers, as well as over the internet.
Normally they come with a thermostat that reads the temperature, and a built-in hydrometer that allows you to set them so that they only operate if the air starts to fall outside of the ambient humidity to which they have been programmed.
Also, they come in a wide range of prices and so you may want to speak to your supplier before making a purchase. You will need to have an idea of the volume of the room in which they will be used, as well as the number of plants that will be in their vicinity.
In general, they fall into two categories. One raises the temperature of the water it contains to create light steam. The second agitates the water so that it creates a light mist.
The mist version will need to be supplied with purified water and the heat version will use more energy. Both of these are considerations you should take into account.
A fairly recent arrival to the home gardener armory is the indoor greenhouse. These are simply miniature greenhouses that enable you to keep your plant in a more confined space that is either walled with glass or clear plastic.
Obviously, smaller spaces make it much easier to keep the air at a humidity that would suit the ideal growing requirements of your plants.
Personally, I find that these devices lack aesthetic appeal. While they may make growing indoor plants, including Pothos, easier, they are not very attractive and as most of us tend to grow plants for their eye-catching appeal; having to include something unattractive in the house rather defeats the objective.
This is one way of raising humidity that has been around for years. Gardeners whose plants were suffering from low humidity would simply spray the leaves with a fine spray of water, and that would have the effect of instantly raising the humidity level.
Recent studies have started to debate the efficacy of this method. Though not yet conclusive, they seem to point to the fact that though humidity does go up when the mist is first supplied.
It then quickly returns to what it was before the treatment as soon as the plant dries up. In addition, the studies also seem to suggest that wetting the leaves can raise the possibility of disease or fungal problems.
It is important to remember that the Pothos is an extremely robust house plant and that it can tolerate a wide range of humidity levels. It is one of the most popular houseplants because it is so tough.
Unless the humidity level in your home was extremely low, I would be tempted to stick with gravel trays and clustering plants and tackle the source rather than simply the problem.
You may be able to reduce low humidity levels simply by adjusting the heating or air conditioning, or by keeping the windows open for just a few hours each day.
Humidity is an important factor in the overall well-being of a plant, even with a plant that is as indestructible as the Pothos.
Once you start to take account of it, even if your plant was doing fairly well, you will find that the Pothos will perform far better.
Because this plant is tolerant of a wide range of humidity levels, it is usually easy to bring them into the ideal range by making just a few simple changes.
- Know your humidity level
- Adopt a good watering regime
- Choose a good potting medium and the right sized container
- Position your Pothos carefully
- Group plants to create a microclimate
- Don’t let the air in the room become stale
By being aware of the potential for this problem to exist, you are able to look out for it and after that, the remedy should be quite straightforward.