Temperature and humidity are two very important variables in successfully growing plants. Some fascinating plants require very specific conditions to thrive. Interesting enough, some require a specific difference between day and night temperature for flower formation, or a specific humidity/temperature combination for maximum fragrance.

The Ideal Conditions

Day temperature in the low 70s° F/ Night temperature in the low to mid 60s° F

Humidity around 50%

…more or less encompasses all indoor plants. It’s warm enough for tropicals to thrive and cool enough for cooler growing species to survive (there are quite a few exquisite higher altitude plants though not all will be happy with those conditions). It’s also a perfect living environment. 40% to 60% humidity is ideal for us humans too. It will take humidity levels to be constantly kept over 60% to promote any mold or rot in the house, so keeping humidity around 50% is more than acceptable.

Temperature

If you prefer warmer conditions you can focus on growing more tropical plants. Those do grow faster and some flower better when the temperatures are higher. If you have a cool unheated sunroom you can grow tons of cooler loving plants with a complete ease. In any home, be it a large house, or even a small apartment, there are different microclimates.  A tad bit closer to the windows in the wintertime will keep your plants few degrees colder than plants further in the house for example. Plants that like it warm and tolerate dry air can be kept closer to the heater and so on. Taking time to notice those spots in you home and choosing the right one for a plant, can be a matter of life and death for it.  

Humidity

Overall, monitoring and maintaining the temperature are fairly easy and straightforward tasks. However humidity is a bit trickier. Keep in mind that your heater and AC both dry out the air.

So how can you tell if you are doing a good job at maintaining a high humidity environment. Of course you can go by how the air feels, and regularly spray the plants that can be sprayed (some plants do not take well on being sprayed and get brown wilt spots).

If like me you have a ridiculous amount of plants, it might be wise to invest in a higher end sprayer. My favorite one is the 2L Solo sprayer with the long nozzle. Though quite expensive, I would highly recommend it. It works by pumping pressure into it and then you can effortlessly spray your numerous plant collection. It has a long nozzle and can be adjusted to spray at an angle (best thing ever when you are watering orchids!). I’ve had two of those for years now and they are very sturdy (they have been through quite a bit of rough handling) and are definitely worth the price. If you have just a few plants a sprayer from the dollar store will be efficient, though they break quite easily; you do get what you pay for.

There are tips in raising the humidity, but often you might overlook that as the cause of your plants suffering. Here are few signs that might suggest a low humidity level:

• Dead/”burnt” leaf edges
• Plant leaves seem more brittle than what’s normal
• Plants being wilted, despite moist soil (that can also be a sign of root rot from overwatering, but if there is no root rot it’s definitely low humidity!)
• Flower buds fail to open or develop
• Increased vulnerability to infestations, especially spider mites and mealy bugs
• Reduced vigor and so on…

I got myself a humidity/temperature monitor, and was surprised at how poorly I was maintaining the humidity around my plants. Not only was it too low, but it fluctuated greatly. It’s an extremely helpful tool to see what works and what doesn’t when trying to maintain your humidity. Not to mention that it’s conveniently cheap/small/ and is battery operated.  I would highly recommend getting one. Here is the one I purchased: AcuRite humidity monitor.

It has worked great since I got it 2-3 months ago. It was the cheapest sensor with the best rating I could find.

So you found out the humidity level in your place is low… Here are a few ways to instantly get the humidity up and/or maintain it that way:

• Keep your plants clustered together to create a higher humidity micro-climate around them
• Place humidity-loving plants on humidity trays (a tray with water and pebbles on the bottom; plants are placed on top of the pebbles so that they don’t soak into the water in the tray)
• Boil water in a wide pan or a kettle with the lid off (the larger the surface area the better the outcome). This works great and you can put up up to several liters of water in the air in the matter of hours. Since I live in an apartment building, there is constant ventilation keeping my place severely dried, and spraying my plants is not sufficient sometimes.
• Smaller plants that are severely suffering can be placed in plastic bags, or grown in a closed terrarium environment.
• The best way to ensure a constantly maintained humidity however is to have a humidifier.

Speaking of humidifiers, there are plenty of options in terms of design, size and mode of operation. Most are silent and extremely efficient; you won’t even notice them on your electric bill (if they are not battery operated).