Why Do Monstera Plants Have Holes? Understanding Their Unique Leaves

Monstera Deliciosa, commonly known as “Swiss cheese plant” or “Split leaf Philodendron” are tropical plants native to the tropical forests of Central America. Monstera Deliciosa are great beginner plants for many plant parents and often times “the plant that started it all”. They’re known for their big, beautiful split leaves. Monstera’s in their early stages of life, in their juvenile form, will have solid, heart shaped green leaves with no holes. With proper care, age and light the leaves will start to mature, double in size and start developing those beloved splits and holes in their leaves.

What is Leaf Fenestration?

Fenestration is the Latin word for “window” and refers to natural holes or splits in the leaves of certain plants, including Monsteras. This term is often used in botany to describe the natural leaf holes or splits in different tropical plants including Monstera leaves. The exact reason for fenestration is still a mystery, but scientists have proposed a few different theories.

A mature Monstera leaf covered in rain drops.
Photo by Nikola Đuza on Unsplash

In their natural habitat, Monsteras start out low on the forest floor. As they grow and mature, they start to grow and attach to tree trunks, growing up towards the canopy reaching for sunlight. This is one of the theories believed to cause fenestrated leaves. Monsteras are constantly being shaded by larger plants, and to make up for this lack of sunlight, they produce foliage with bigger, wider leaves to reach as much sunlight as possible. The splits and the holes are the places the sunlight doesn’t reach. These holes also help capture 'sun flecks', which are small beams of sunlight that penetrate the dense canopy. And Monsteras are believed to do this to help preserve nutrients.

Another popular theory is to help adapt to the weather. Tropical forests are prone to intense rains and high winds. These high winds, often uproot plants which can be detrimental. Over time, Monsteras adapted these fenestrations to allow intense winds to pass through the leaves without damaging and uprooting the plant.

The last theory revolves around rainfall. With Monstera leaves being so massive, if the leaves didn’t have these holes, all the rain would sit on the leaves and never reach the roots. Not only would this deprive the plant of needed nutrients but standing water on leaves cause fungal infections. These holes help keep infections at bay and ensure the plant gets water.

Monstera leaves with splits and fenestrations
Photo by Kara Eads on Unsplash

Factors That Influence Fenestration

There’s many factors to consider when trying to grow fenestrations on the leaves of a Monstera, a tropical plant. So, if you’re trying to grow an iconic Monstera and have it produce fenestrated leaves, take note of these elements that might influence your Monstera's growth.

Age

• Monstera plants develop fenestrated leaves as they mature, with young plants having small, solid, heart-shaped green leaves similar to those of the Philodendron.

• As the plant grows, the leaves increase in size and develop deeper cuts, resulting in fenestrations.

• Patience is key, as it may take time for a young Monstera plant to develop fenestrations.

Light

• The splits in the leaves allow light to pass through to the plant’s lower leaves, promoting healthy growth.

• Monstera plants require consistent bright, indirect light to grow split leaves as they grow and mature. Indirect light means the plant can still see the sun but doesn’t have direct sunlight touching the foliage. In tropical forests, Monstera plants have adapted their leaf structure to capture 'sun flecks', which are small beams of sunlight that penetrate the dense canopy. If you think your Monstera leaves aren’t receiving enough light, slowly acclimate it to a brighter light area.

• A Monstera grown in low lighting conditions will not grow fenestrations and will start to push out small leaves to conserve energy.

• Consider giving your plant a grow light if you lack natural light. You can read here to learn more about grow lights.

Feeding your Monstera

Another aspect to consider, when wanting to produce foliage with larger leaves on your Monstera, is food. While your Monstera might’ve been growing fine without getting fertilized on a regular basis, I would suggest feeding it on a monthly basis if your leaves seem lack luster. Like other aroids, Monsteras can be vigorous growers and when giving the proper nutrients, I’m sure you’ll start to notice faster leaf growth and more holes.

A cluster of Monstera leaves
Photo by Olena Bohovyk on Unsplash

Click here to read all about fertilizer and choosing the best one for your plant parenting habits.

Caring for Your Monstera Plant

We’ve talked about sunlight and fertilizing your Monstera, but what other care requirements may it need?

Soil

Monsteras have big, juicy roots that resemble Udon noodles. While these roots aren't super susceptible to root rot, they will benefit from a chunky, air mix. If you prefer to make your own mix, I would recommend using a houseplant potting soil mixed with perlite, orchid back, and horticultural charcoal. Each of these amendments have different benefits they offer to the soil. But, if you prefer to buy something already made, I highly recommend Sol Soil.

Next, always make sure to consider the type of planter your Monstera is planted in. Terracotta is great if you tend to over water. Terracotta is porous and will help wick away moisture faster. While, ceramic is great at keeping moisture in. So, if you tend to forget to water your plants, go for ceramic or plastic pots. And, to save yourself on extra work, make sure the planters have drainage holes for water to drain out the bottom.

Houseplant pests

Like many other plants, Monsteras can succumb to houseplant pests, especially with such big leaf surface. Monsteras are most prone to spider mites and thrips. To keep plants at bay, get in the habit of checking the leaves when you water your plant. Look for webbing, little insects crawling on the leaves, yellow stippling or any abnormal signs of damage.

Regularly inspecting the foliage and catching houseplant pests early, will save your plant and your sanity. Click here to read more about common houseplant pests.

Support

We haven’t talked about the importance of support yet. As mentioned earlier, in their natural environment, Monsteras attach to other plants and grow up towards the sun. Attaching to other plants gives them a sense of security. When they’re securely attached to something, they know they can comfortably produce larger leaves and start creating those holes and fenestrations. And yes, an old Monstera can produce holey leaves without support, but when you add support early on, your chances of growing leaves with holes are significantly increased.

I would recommend the Zella trellis by Treleaf. It’s a modular trellis, meaning it grows with your plant, and is made from cedar wood. The natural cedar wood mimics their native habitat. You’ll start to notice how quickly the aerial roots attach to the cedar. With a little bit of time, your leafy structure will produce foliage with unique holes and some leaf fenestration.

Humidity

Even though, Monsteras are use to high humid environments, I would say they're pretty tolerable of different humidity levels. Anything above 30% humidity is fine for Monsteras. However, if you notice your Monstera leaves are getting stuck when they're growing or not properly unfurling right, consider upping the humidity. This can be done by adding a humidifier to your plant area or sticking it in a greenhouse.

Common Problems with Monstera Leaves

• Yellowing leaves are often a sign of overwatering, while browning leaves can be caused by low humidity and dry soil.

• Leaf droop can be caused by underwatering, root rot, and low humidity.

• Leaf curling can be a sign of stress, often caused by compacted soil, lack of nutrients, or extreme temperatures. Monsteras, native to tropical rainforests, have evolved to thrive in environments with abundant rainfall and specific conditions.

• Prune yellow leaves occasionally, but avoid removing more than one-third of the plant at once to avoid stress and shock.