Why Are My Monstera Leaves Turning Yellow And How To Fix It

Monstera deliciosa, commonly known as the Swiss Cheese plant, is a tropical vining plant, native to South America. It loves humid conditions and filtered sunlight so if you can mimic this at home, your monstera can thrive, even under fluorescent light. 

According to the University of Oxford,  they have an impressive ability to thrive, even when available light sources are scarce. In fact, it is known as being very hard to kill, so to see the glossy green leaves turning yellow can be a huge disappointment. 

In this article, I’ll detail why your Monstera is turning yellow and the measures you can take to prevent or fix it. Read on for tools and insights that can be implemented to give your Monstera everything it needs to prosper.

Why Do Monstera Leaves Turn Yellow?

Before detailing the reasons for yellow leaves, it’s useful to understand some basics of photosynthesizing. Plants can create a pigment containing chlorophyll and it is this important pigment that gives plants their unique color. 

The first sign of a decline in this substance is that the once bright green, vibrant leaves will turn yellow. This is called Chlorosis and should be a wake-up call that your plant is not happy in its surroundings.

Without sufficient chlorophyll, plants cannot make the carbohydrates they need via photosynthesis and cannot produce green leaves. This, in essence, is when Chlorosis occurs.

Causes of Monstera Leaves Turning Yellow

To understand why the leaves of your Monstera are turning yellow, you need to identify what is causing this chlorosis, because yellowing leaves are simply an outward manifestation of a deeper problem. 

Some likely culprits are nutrient deficiencies in the soil or improper soil pHs such as a deficiency of macro or micronutrients.

Other reasons for yellowing leaves include irregularities with water, poor soil conditions, temperature fluctuations, and fungal infections. 

Fortunately, most of these problems are easily fixed as long as diagnosis and treatment are applied early on. In this article, I will give you all the information you need to discern the underlying concern and deal with it effectively.

1. Nutrient Deficiencies and Soil pH

In their native surroundings, Monstera can absorb all the nutrients they need from the loamy, nutrient-rich soil of a tropical rainforest floor in order to retain their lush, green allure.

It’s unsurprising then that after a year or two in the same pot, your Monstera houseplant may well begin to show signs of a nutrient deficiency. This will manifest as yellow leaves and stunted growth.

Soil for Monstera needs to be neutral or slightly acidic and within a pH range of between 5.5 to 7.0. Checking the pH of your Monstera is easy if you have a soil test kit and will enable you to detect any nutrient deficiencies in the soil.

Maintaining correct soil pH is important because some nutrients are only accessible by plant roots at specific levels of acidity or alkalinity. 

Nitrogen Deficiencies in Monstera

Monstera plants need nitrogen to make the chlorophyll necessary for new growth and strong roots. Any shortfall of this vital macronutrient will lead to the yellowing of leaves and a slowing down of growth, especially in the growing season.  

Nitrogen is soil soluble, which means it is easily leached out, especially with too much irrigation or when using a fast-acting liquid fertilizer to supplement nutrient deficiencies.

Fixing Nutrient Deficiencies in Monstera

Indoor-grown Monstera needs good quality potting soil that is nutrient-rich and well-draining. They also prefer a slightly acidic soil pH in the range of 5.5 to 7.

If you suspect a nutrient deficiency, it is worth conducting a soil pH test to help you establish any specific nutrients that are lacking in the soil.

To supplement nutrients that may be lacking in potting soil, the University of Florida recommends fertilizing in April and August with a general-purpose fertilizer that includes the three primary macronutrients, plus trace elements of magnesium.

I recommend using a slow-release fertilizer with a gentle 3-1-2 NPK as this helps to avoid any potential over-fertilizing issue.

The enhanced nitrogen ratio of a 3-1-2 NPK encourages healthy foliage growth, and the addition of potassium supports robust root development and also supports the plant’s ability to absorb water, oxygen, and nutrients.

2. Watering Issues

When it comes to water, Monstera can be choosy. Not only do they dislike soggy, overwatered soil and roots, but they are also particular about the number of chemicals that are contained in water. 

However, although watering issues are one of the most likely causes of yellow Monstera leaves, it is also one of the easiest problems to solve. 

Overwatering

Too much moisture prevents soil from circulating oxygen and this in turn means that roots will quite literally suffocate.  Often the cause of overwatering is due to poor drainage or simply not having a watering routine and then overcompensating. 

An overwatered monstera is easy to diagnose. The most likely symptoms include yellowing on older, lower-level leaves followed by wilting, dark spots, and a foul smell being omitted from soggy soil.

Overwatered monstera leaves
Overwatered monstera leaves

If you have assessed that your Monstera has been overwatered, don’t take these signs lightly. Remove it from the soil as soon as you can to prevent further damage. 

Brush any excess soil from the roots and then carefully examine for signs of rotting roots. If you do find black, brown, and mushy areas of the roots you will need to trim them away carefully using sanitized scissors. 

Allow your Monstera adequate time to dry out before repotting and ensure that going forward your watering schedule is more modest, and you allow all excess water to drain from the bottom of the pot before replacing your plant in the catch tray.

I like to wait until the soil is about 50% dry before watering Monstera. These are hardy and independent plants, preferring to dry out a little rather than be drowned. 

Check that your pot has enough drainage holes and is not clogged by debris. Most of all, never let your Monstera sit in a stagnating pool of water that has collected in the catch tray. 

Using Poor Quality Water

Tap water contains chemicals including chlorine, which although safe for human consumption, can be very harmful to Monstera. Chlorine can also kill beneficial soil microbes that otherwise enable plants to absorb nutrients.

Signs your plants have been overexposed to chlorine include crispy brown leaf tips, chlorosis, stunted growth, leaf drop, and dry leaf veins and tips. 

Tap water chemical burn
Tap water chemical burn, causing brown crispy edges

I recommend using rainwater for Monstera although it’s fine to use filtered water at room temperature too. 

3. Sun Scorch

Monstera like to grow under the canopy of larger trees and climb through the branches, basking in dappled light. So it stands to reason this will be their preferred lighting conditions as a houseplant too, filtered light or bright indirect sunlight.

If Monstera receives hours of direct sunlight, they can suffer from leaf scorch, whereby the leaf will turn pure yellow, and ultimately brown off and die.

4. Poor Soil Quality

Monstera needs loamy, nutrient-rich, well-draining soil. Without proper drainage air circulation is not possible, oxygen cannot circulate and the ability to absorb nutrients is inhibited. 

Poor drainage issues manifest as sickly and yellow-looking Monstera leaves as well as stunted growth.

I recommend a potting soil mix of between 5.5 to 6.5. Preferably 1 part peat moss/coco coir, 1 part perlite, and 4 parts pine bark fines. 

Add these parts to a large container with just enough water to make it moist. Alternatively, there is some excellent quality ready-to-use potting soils available to buy however, you may need to add a little grit or perlite to help with drainage.

Don’t forget to use a pot with sufficient drainage and never allow water to pool in the catch tray. 

5. Incorrect Temperature

Any sudden fluctuations in temperature will cause the leaves of your Monstera to turn yellow as it uses up vital energy in an attempt to adjust to the sudden change. 

Like all plants, Monstera needs consistency and reacts poorly to extremes by displaying visible symptoms with distressed foliage being the most immediately apparent. 

Being tropical plants, Monsteras are used to humidity in the region of 60 to 80% and temperatures of 65°F and above. If your home gets too cold or your region is generally dry, you could see some real damage. 

Monsteras are canopy plants preferring indirect sunlight and sheltered areas. They dislike drafts and sudden changes in temperature or humidity. I find a bathroom with a good deal of indirect light is a good place for Monstera but avoid locating it on a window ledge. 

6. Aphid Infestation

When pests attack your Monstera it will often result in yellow leaves or a yellow-mottled pattern that resembles a virus. This distinctive leaf discoloration is where they have used their mouthparts to suck vital nutrients and feed on the plant’s tissue. 

If you suspect an infestation, be sure to thoroughly inspect your plant, particularly on the underside of leaves, on nodes, and at leaf junctions. If you find one, there are sure to be more, and it will need to be treated as soon as possible. 

First, wash stalks and leaves thoroughly. Next, use a good quality horticultural oil to disrupt the metabolism and feeding habits of aphids. Remember, they can carry disease and spread to other nearby plants so using horticultural oil is a good way to prevent viruses as well.

You might also like to read Moss Pole For Plants: Why, How, And When To Use

Citations

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Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.