Hoyas are one of my personal favorite plants and I’ve been keeping them for a few years now, over this time I’ve read a lot about hoya humidity so I’ve decided to write this guide to set the record straight.
A lot of hoyas thrive in high humidity between 60% and 70%, but they can definitely be kept at lower humidity levels as I have discovered throughout my years of ownership. There are also certain varieties of hoya that require less humidity (around 50-60%).
In this article I’ll cover everything there is to know about hoya humidity levels, so let’s get straight into it.
- Ideal Humidity Level For Hoyas
- Why Does Humidity Matter For Hoyas?
- Examples Of Low Humidity Hoyas
- Symptoms Humidity Is Too Low
- Symptoms Humidity Is Too High
- How To Measure Humidity
- How To Increase Humidity For Your Hoya
- What About Decreasing Humidity?
Ideal Humidity Level For Hoyas
As I mentioned before, you should really aim for a humidity level of around 60%-70% for most hoyas. There are certain varieties of hoya that don’t require as much humidity, and I’ll provide a few examples of these shortly.
Why Does Humidity Matter For Hoyas?
Hoyas prefer high humidity as they are native to areas where humidity is high and have therefore adapted to those conditions.
Scientifically, humidity affects stomatal openings, which are tiny pores on the leaves of plants that play a vital role in photosynthesis.
Stomata open and close depending on both temperature and humidity, and hoya have stomata that have adapted to high-humidity environments. For example, it is shown that leaves grown in higher humidity environments develop larger stomatal openings.
Another adaptation of hoya to high humidity is that the leaves have pointed ends, known as ‘drip tips’. These allow water to flow off the leaves when humidity is high, rather than potentially causing mold.
Examples Of Low Humidity Hoyas
Not all hoyas are the same, and certain varieties can grow perfectly well without high humidity.
A few examples of this include nummularioides, rotundaflora and mathilde. I recommend checking the care requirements of your specific hoya before you assume that the humidity level is either too high or low.
What If You Can’t Provide The Right Humidity?
If you can’t provide the ideal humidity levels then don’t worry.
I’ve kept a few hoyas (one of my recent purchases is shown above) and the humidity in my apartment is usually between 50% and 60% and I have had no issues. You can expect the growth rate to slow down a little, but the overall health of your hoya shouldn’t be affected too much.
There are cases where it can be a problem though, particularly if your humidity is way higher or, more commonly, much lower than the 60-70% range.
Symptoms Humidity Is Too Low
If the humidity for your hoya is below 50% then you will likely encounter some of the symptoms listed below.
Low humidity specifically affects the tips of hoya leaves and causes them to turn brown.
This occurs as transpiration increases due to the lower relative humidity of the air, which causes the leaves to lose moisture more quickly starting at the edges. This can sometimes be mistaken for underwatering, but underwatering would cause the leaf edges to turn brown rather than the tips.
Another common symptom of low humidity is curling leaves, which is again a result of moisture loss from the leaves due to increased transpiration.
Symptoms Humidity Is Too High
60-70% humidity is pretty high as it is, but if the humidity around your hoya is even higher than this it can cause some problems.
Please note that this is quite rare, but it can be possible if you keep your hoya somewhere like a kitchen or bathroom.
Humid environments are perfect for mold and fungi to thrive, and even though hoya leaves are good at dripping water they can’t remove all of it, especially if the humidity is very high.
If the humidity is very high then it can become very easy to overwater a hoya.
Transpiration decreases when the humidity is high. This means that less moisture is lost from the leaves and your hoya needs less water overall.
If you continue to water like normal then you will quickly overwater your plant. The key signs of an overwatered hoya are listed below:
- Yellow Leaves
- Wilting Leaves
- Saturated Soil
Root rot is very likely to develop in overwatered conditions so it’s crucial that you water your hoya less if the humidity is too high.
How To Measure Humidity
Before you take any steps to alter the humidity, it’s crucial to measure it first so you know that humidity is a problem.
A hygrometer is the easiest way to do this. They cost around $10 to $20 and give a pretty accurate reading right away, so there isn’t much hassle in using them.
How To Increase Humidity For Your Hoya
Once you’ve measured the humidity you will likely need to increase it.
Here are a few tips for doing that without breaking the bank.
Pebble trays are great for increasing local humidity around your hoya.
The theory behind these is simple; as the water from the pebble tray evaporates the humidity above (where the hoya is) will increase. To make a pebble tray simply fill a small dish with some pebbles and then add water to about half of the remaining volume.
Place your hoya on top of the pebbles and make sure it is even and that’s it.
Place Next To Another Plant
This works because both plants will transpire, increasing the amount of moisture in the air locally and therefore the humidity goes up.
Honorable Mention – Humidifier
Humidifiers can be quite expensive, but they are the best option if you want to increase the humidity to a guaranteed level with very little effort.
I personally only recommend this if you have lots of houseplants that like high humidity or if you live somewhere where the humidity is very low.
What About Decreasing Humidity?
If the humidity is too high then it’s likely just a case of moving your hoya to somewhere with lower humidity.
Humidity higher than 70% is very rare to find inside a house so there will be several places where you can move your hoya to have more success with growing it. You should also check the soil carefully for signs of overwatering and wipe down the leaves if moisture starts to build up on them.