Monstera Deliciosas are sought-after for characteristic lobes and holes in their glossy green leaves. So it can be frustrating if you’ve lovingly cared your Monstera, but its leaves remain unfenestrated (whole).
In this article, we’ll detail the top 3 reasons for leaves not splitting, from the most common reason to the least:
- Too young. Only at 2-3 years old do Monstera Deliciosas typically start to develop lobes;
- Insufficient sunlight. Monsteras need ample amounts of bright, indirect light. Insufficient light leads to stunted growth, smaller leaves and ones that remain in their juvenile state.
- Poor overall health of the plant. While Monsteras are considered fairly hardy plants, less than optimal care conditions lead to a decline in health. We cover the 5 most common reasons why:
- Over or under-watering;
- Inappropriate potting mix;
- Too low humidity or temperature;
- A lack of macronutrients;
- Pest infestation;
- A root-bound plant.
We’ll also provide specific guidance to determine the reason why your Monstera is not splitting, and provide concrete steps to remedy these.
Table of Contents
#1: Your Monstera is too Young
One reason why a Monstera hasn’t split yet is that its simply too young. It is common for Aroids to look quite different in their juvenile states compared to when they are mature!
Juvenile Monstera leaves emerge light green and whole as they unfurl, and typically take up to 2-3 years for the outer edges for your plant to form lobes. As they grow, the light green deeps to a darker forest green color.
Thereafter, when about 4 years old and under optimal growth conditions, they develop secondary fenestrations. This is in the form of small holes along the midrib of each leaf blade. Unlike the lobes, these small holes don’t expand to the outer edges of the plant.
Fenestration (leaf lobes and holes) is a natural adaptation of the species that allows light and water to pass through mature leaves to lower leaves and roots, thereby nourishing juvenile lower leaves. A study by the University of Colorado found that fenestrations in Monstera leaves allowed for significantly more water to be captured by roots than those without fenestration.
Another function of fenestration is to help your large leaf to withstand windy conditions. In the wild, leaves can grow up to 3.3 feet (1 meter) long! Given its thin and broad shape, even a light breeze may cause unfenestrated leaves to flap.
What if I don’t know the age of my Monstera?
If you’ve recently purchased Monstera of an unknown age, another way to check if you should expect splitting is to measure the size of the leaf. If the leaf is less than 5 inches (13cm) long, it will likely have some growing to do before it splits. So all you have to do is be patient. 🙂
However, at 5-6 inches (13-15cm), you should expect a healthy Monstera with sufficient sunlight to start splitting.
#2: Insufficient Sunlight
When it comes to growing your Monstera indoors, it’s critical that your plant gets enough sunlight. Sunlight is an irreplaceable component of photosynthesis, which is crucial for leaf growth and overall health.
What is sufficient sunlight? While your Monstera grows best in bright, indirect light, many people underestimate how much light this means.
To be specific: Choose a bright spot in your home that receives between 300-400 foot candles (use a light meter to check), for at least 8 hours a day. Direct light is okay for up to 2-3 hours a day, but the vast majority of the light should be indirect.
As East-facing windows provide a few hours of gentle morning light and indirect light for the rest of the day, they are typically best suited for Monstera growth.
West or South-facing windows can work too, but you’ll need to place your plant around 4-5 feet (1.2 – 1.5 meters) away from the windowpane to lessen the light intensity.
If you don’t have a light meter on hand, another way to gauge light intensity is by placing your hand 12 inches (30 cm) away from your Monstera’s leaves, in the direction of the light source. Your hand should cast a dark shadow with slightly blurry edges – this is bright, indirect light.
A crisp shadow with defined edges indicates direct light (okay for up to 2-3 hours a day only, before you start risking pale, sunscorched leaves).
On the other hand, a barely-there shadow or no shadow at all means the light is definitely not strong enough! Remedy this by using a grow light to supplement natural light.
Signs that your Monstera is not getting enough light
Other signs that your Monstera is not getting sufficient light include:
- Leggy growth. If you notice that your Monstera has long petioles (the stem that attaches the leaf to the main stem, this is a sign that your plant is (quite literally) reaching for more light. Leaves also tend to be small.
- Soil takes a long time to dry out. If the topsoil remains damp for 5 days or more, this is a sign of low evaporation rates, pointing to too-low light intensity.
Pro-tip: use a Moss Pole
Besides relocating your plant to a brighter spot, another way to help your plant reach more light is to use a moss pole. What does this have to do with light levels? Read on.
Monstera Deliciosas grow in their natural habitat as hemiepiphytes. This means starting life on the forest floor, before using their aerial roots to grab onto a host tree and climb upwards. (Read more about aerial roots here.) This climbing habit helps your plant prop its leaves higher in the canopy, where it can reach more sunlight.
Do the same in your home! By encourging its climbing habit, your Monstera will grow tall – and in doing so, make the best use of available sunlight.
#3: An unhealthy Monstera
If your plant is more than 3 years old and receives sufficient sunlight, a possible reason why your Monstera is not splitting is due to poor health.
To check if your plant is healthy, ask yourself these questions:
- Has your plant developed new leaves in the past 3 months?
- Are the leaves discolored?
Of course, poor health can arise from several different issues, but there are common 5 reasons we’ve put together after evaluating frequent complaints.
1. Over or under-watering
Improper watering is by far the most common reason for an ailing Monstera. Here’s how we make sure our Monstera is well-watered.
- When to water: using your finger, check that the top 2 inches of soil is dry before watering. If the soil is still slightly damp, don’t water, and check back again in a day or two.
- How to water:
- Water slowly and deeply near the soil line until the potting mix is saturated and excess water escapes from the drainage hole. We use a long-spouted watering can that helps us avoid wetting the leaves.
- Make sure to empty the saucer so that your plant is never sitting in a pool of stagnant water. A terracotta planter also helps excess water to evaporate easily from the surface.
It’s important to use this method of checking when your plant needs watering rather than blindly following a watering schedule. This is because seasons, evaporation rates, and growth rates change over time — meaning the amount of water your plant needs also changes!
It is not uncommon for Monsteras to need 1/2 or 1/3 the amount of water in winter as they did in summer. Follow this method so that you aren’t accidentally over or under-watering your plant.
Signs of overwatering and underwatering
You will know your Monstera needs watering when the leaves curl inwards and develop brown, crispy tips.
On the other hand, yellowed leaves with soft, droopy stems are a sign of overwatering. Use your finger to check the soil moisture to confirm.
2. Inappropriate potting mix
The second part of making sure that your Monstera is properly watered has, ironically, nothing to do with watering practices. 🙂 It has to do with having the right potting mix that holds enough water to nourish your Monstera, but not so much that it suffocates its roots.
The whole problem of waterlogged roots is that it crowds out air particles, such that your Monstera literally cannot breathe. And for a hemiepiphyte that lives above-ground for most of part.. that’s bad news.
What to do then? Try our favorite potting soil for Monstera Deliciosas. Mix together:
- 1 part high-quality indoor potting mix
- 1 part pumice
- 1 part orchid bark
- a handful of horticultural charcoal
You want to have a mix that has at least 2/3 drainage elements (pumice, orchid bark, and horticultural charcoal), and 1/3 of a high-quality, light potting soil.
If you’re open to semi-hydroponic solutions, you can also use LECA to grow your Monstera.
3. Too-low Humidity or Temperature
When it comes to humidity and temperature, the higher the better for your tropical plant. Ideally, shoot for >70% humidity, though above 60% is a good effort. If you live in a dry climate, you may want to invest in a humidifier to achieve these levels.
Temperature-wise, keep your Monstera in mild indoor temperatures between 65-90 degrees F (18-29 degrees C). They are not cold-hardy, so dips below 60 degrees F (15 degrees C) can cause damage.
However, they can be grown outdoors year-round in USDA hardiness zones 10 through 12.
4. A lack of Macronutrients
While the majority of nutrients for your Monstera comes from sunlight and soil mix, light fertilizing ensures that your plant is not lacking any macronutrient. A lack of nutrients can cause yellowing and unhealthy leaves.
We like using Dyna-gro Foliage Pro, which is a gentle houseplant fertilizer that is nutritionally complete. Apply this at half strength, once a month during the spring and summer active growing months. Don’t fertilize in fall and winter.
If you live in a country near the equator without seasons, you can continue to fertilize year-round as your plant actively grows throughout the year.
When choosing a fertilizer, pay attention to the NPK ratio. These are the ratios between Nitrogen, Phosphorous, and Potassium contained in the fertilizer. While all three macronutrients are needed in any plant, choose a NPK ratio of around 9-3-6 for your Monstera.
Being a heavily foliage plant, a high nitrogen content encourages healthy and lush leaves.
Other than the “big 3” macronutrients, another important nutrient for Monsteras to consider is magnesium. Magnesium helps your plant develop chloroplasts for photosynthesis. A magnesium deficiency can lead to yellowing leaves.
We like Dyna-gro Foliage Pro that ticks all the boxes.
5. Pest infestation
Though Monsteras are fairly pest-resistant, sometimes the occasional bug is unavoidable. If you spot any of the below common houseplant pests, this is likely the issue for your ailing Monstera:
- Mealybugs – appear like bits of white cotton balls with clearly segmented bodies around 1/10 – 1/4 inch (0.3-0.6cm) long. They like clustering together and are commonly found around new growth and hard-to-reach spots.
- Scale – close cousins of mealybugs, scale often look like immobile shell-like bumps that are clustered together, usually between 1/16 – 1/8 inch (0.2 – 0.3cm) long. They come in many colors but usually appear tan, black or brown.
- Spider mites – Being less than 1/50 inch (0.5mm) long, spider mites are hard to see without a microscope. However, fine webbing under the leaves and stems indicates the presence of spider mites. You may also observe faded and greying leaves, as spider mites suck out the chlorophyll.
- Aphids – these are light green and pear-shaped, about 1/8 of an inch (0.3cm) long. However, there are over 5,000 species of aphids that also come in black, pink, and white.
- Fungus Gnats – attracted to overwatered plants, fungus gnats are black flying insects, usually around 1/8 inch (0.3cm) long, and look like fruit flies.
How to get rid of pests
Here’s how to nurse your Monstera back to good health:
- Thoroughly inspect all your plants.
- Quarantine any infected plants away from all other plants to prevent cross-infection.
- Using sterilized garden shears, trim off any visibly damaged or heavily-infested parts of the stems and leaves. We use 70% isopropyl solution to sterilize our gardening tools; this is important as cross-contamination is a common cause of spread.
- Apply an Insecticidal Soap spray to the remaining stems and leaves. Reapply as necessary and as the instructions dictate until you see that the infestation has been eradicated.
- Apply a dilute neem oil solution to all other plants as a preventative measure against infestation. Neem oil is a natural broad-based pesticide that disrupts the growth of larvae and prevents feeding, growing, and reproducing.
6. A Root-bound Monstera, with no space to grow
When your plant is root-bound, it means that its rootball has grown too large for the size of the pot.
Roots start to compact and press against each other until they become a single, overgrown mass. Because they are so tightly squeezed, they cannot breathe easily, let alone effectively draw water and nutrients from the soil.
On top of this, the volume of soil in the pot becomes insufficient to support the needs of overgrown roots. Deprived of sufficient water and nutrients, your plant becomes thirsty and malnourished, leading to poor health.
Signs of a root-bound plant
These are the most common signs of a root-bound Monstera:
- The plant grows much more slowly than usual and has crispy brown or yellow leaves.
- Your plant appears as if it never has enough to drink, no matter how much you water it. Additionally, water takes a long time to drain through the plant. This points to a very densely-packed pot. In severe cases, however, water drains through immediately without being absorbed.
- Your plant has roots emerging from the bottom of the drainage hole or has roots appearing above the soil.
- In extreme cases, your container may be warped due to the pressure of the tightly-squeezed roots pressing against the container. (Of course, this is only applicable if you are using a malleable container).
How to repot your Monstera
If you have a root-bound Monstera, repot in a larger container. This is best done in spring.
- Water your plant 24 hours prior to repotting – this helps your wriggle your plant free from its pot more easily, and reduces the risk of transplant shock.
- Prepare the new pot, fresh potting mix, and sterilized shears. Ensure the new pot has drainage holes, and choose one about 2 inches (5cm) bigger than the original. Prepare fresh soil, as nutrients deplete over time.
- Fill your new pot 1/3 of the way with fresh soil.
- Now, place your Monstera on its side, and try to dislodge the plant out of its pot.
- Once you wriggle the plant free, use your fingers to gently loosen compacted soil away from the rootball.
- Examine the rootball. Healthy roots are white and firm. If you see any mushy or discolored roots, snip these off with the sterilized shears.
- Plant your Monstera in its new pot. Add more potting mix to fill the pot and secure your plant in place.
- Refrain from watering for a couple of days to allow your plant to settle into its new pot.
We hope this guide has been helpful for you to diagnose why your Monstera is not splitting. Check out the Rhaphidophora Tetrasperma next!
Deborah is a plant enthusiast and founder of Gardening Collective.