Do you have a Fern that appears to be in despair or an Alocasia that seems ready to give up? Perhaps you recently acquired some vibrant Calatheas, but over time, you notice their lush leaves turning crispy and the new unfurling leaves already damaged! The culprit behind these issues could be the lack of humidity in your home.
Maintaining adequate humidity is crucial for tropical house plants. Higher humidity levels enhance photosynthesis, thereby increasing the rate of growth, which sounds quite beneficial, doesn't it? The stars of the show in this process are the Stoma and Stomata. The Stoma consists of microscopic holes that act like pores on the surface of leaves, regulating gas exchange for photosynthesis.
As the interface between the leaf and the atmosphere, the Stoma play a vital role in preventing the unnecessary loss of important molecules while they are open. The cells located just inside the Stoma attempt to capture CO2 for photosynthesis. These cells are relatively moist, and when exposed to dry air, they can lose water molecules through evaporation.
When the air is dry, the Stoma close to prevent water loss, but this closure also means they are unable to absorb CO2 from the air. In high humidity conditions, the concentration of water vapour in the air is typically higher or at least similar to the concentration of water in the moist cells. As a result, there is minimal evaporation of the plant's water. This is beneficial because the Stoma can remain wide open, absorbing ample amounts of CO2 while the plant doesn't have to worry about losing water.
Let's not forget about O2! Another function of the Stoma is to serve as an outlet for oxygen, a waste product produced during photosynthesis. When the Stoma is closed due to dry air, the plant cannot effectively expel this waste. When the balance between O2 and CO2 is disrupted, it slows down photosynthesis. O2 binds to important enzymes used in photosynthesis, preventing them from efficiently breaking down CO2.
We are starting to grasp how humidity affects the ingredients required for photosynthesis. Photosynthesis produces carbohydrates that plants utilise as building blocks for new tissues, including the gorgeous foliage we all adore. Without sufficient humidity, these essential ingredients become imbalanced and scarce, resulting in slowed growth and the development of weak, undersized leaves that nobody wants.
Plants in your home generally prefer humidity levels around 60%, which is significantly higher than what most UK home environments offer. Unusual and delicate plants may even require higher humidity levels.
For extremely humidity-sensitive plants, we recommend placing them under a cloche, in a terrarium, or within a cabinet. This provides a consistent and humid environment, which helps them thrive.
If you're just starting out, we suggest purchasing a hygrometer to measure the humidity levels in your home. If you find that your space naturally has low humidity, there are various ways to increase it.
Humidifiers have become a popular necessity in the plant community as they allow you to recreate the key element found in jungle environments. While it may be a slightly costly investment, humidifiers offer additional benefits such as improving skin health, air quality, and the condition of furniture and wood.
There are other methods to increase humidity as well. Although misting plants provides a temporary solution, you can also use pebble trays and group plants together to create a microclimate that raises humidity.
During winter, maintaining consistent environmental conditions becomes more challenging due to central heating, fireplaces, and other sources of heat. These can cause the air to dry out quickly, leading to plant struggles during this season. It's essential to closely monitor humidity levels during winter. If you decide to use a humidifier during the winter months, be mindful not to leave it on for extended periods. Insufficient airflow in a stagnant environment may promote unwanted mold growth.
Keep in mind that in the UK, humidity tends to drop significantly when external doors or windows are open, so be mindful of your plants' surroundings. Remember, consistency is key! If you maintain a consistently warm environment while keeping humidity around 60%, you should see your finicky plants start to appreciate it.