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There are eight main reasons why your Monstera leaf is turning yellow, but it can be difficult to work out the cause of your Monstera’s issue.
We start with the most common reasons – in fact, it’s pretty likely to be either overwatering or old age, with a little sprinkling of thrips in there too.
This advice broadly applies to all house plants, BUT there are some things (again, thrips) that are more common to Monstera – I’ll point them out as we go along.
- Old age
- Seasonal changes
- Fertilizer issues
- Light issues
- Humidity issues
Overwatering is the most common cause of yellow leaves in Monstera
First of all, does your pot have a hole in the bottom?
If it doesn’t, FIX THAT. Gravel in the bottom of a pot does NOT equal drainage. Read all about holes in pots here.
There are people out there that use pots without holes in and never get root rot, but they were chosen by god to have an easy life. We are not them.
Monstera may not need as much water as you think they do. I have an article about watering them if you’re not sure how much and how often to water them.
If you’re watering too frequently, you can end up with root rot.
When the soil is too wet, oxygen levels within the soil are depleted because the air pockets within the soil fill with water. The anaerobic bacteria that cause root rot can thrive, and the roots will rot.
Over a surprisingly short space of time (like, a couple of weeks in some instances) the Monstera leaves will start to yellow, as the root system is no longer big enough to sustain the plant.
DO NOT PANIC.
Monsteras are really, really good at recovering from root rot. Even if the majority (or all) of the root system has rotted away, you can propagate the nodes and have your plant restored to its former glory in a few months.
One of the problems with overwatering is that it’s easy to accidentally overwater, even if you’re diligent about making sure that you’re only watering when the soil is dry, so make sure you’ve checked these six causes of overwatering by proxy before ruling out root rot entirely.
The material your pot is made of has a massive impact on the time it takes for the soil to dry out.
Terracotta dries out rapidly, and ceramic and plastic dry out more slowly.
Choose your pot type depending on your watering style – overwaterers, you guys go with the terracotta. Underwaterers stick with plastic.
I'd also recommend that you stick with plastic and ceramic if you're not sure what your watering style is. Terracotta is pretty unforgiving, especially in summer, and if you go on vacation your plants might dry out before you've even gotten out of your garage.
This is something that crops up a LOT on social media – people asking why their plant is dying and the plant is a two-leaf cutting drowning in a 20-inch pot.
People are terrified that their plant is going to be rootbound, but I assure you, plants aren’t that bothered about being rootbound – they’d much rather be in too small of a pot than too big of one.
I keep my plants in their nursery pots for as long as possible and only go up one or two pot sizes when it comes to repotting. There’s a detailed guide to repotting house plants here that goes through how to tell when it’s time to repot.
Like with pot material, I recommend tailoring your soil mix to your watering style rather than to the specific plant.
Choose a very well-draining potting mix, with a high proportion of perlite, pumice, or orchid bark (or a mixture). If you want to buy pre-mixed house plant soil, then add some orchid bark to help with drainage.
Choose a potting mix that retains more water. Store-bought house plant potting mix is probably a good option for you.
In summer the light is brighter and the sun is out for longer. Any water in the soil will evaporate more quickly than in the summer. In winter, you can end up with yellow leaves if you don’t reduce the amount you water.
(If your light/temperature stays pretty level year-round then you may find that your Monstera’s watering schedule stays the same.)
Humidity & temperature
If you have low humidity, the water can be pulled from the soil into the dry air – especially if there’s wind or a draught. High humidity, however, can cause soil to stay moist for much longer, so keep an eye out for that.
If you have a humid environment that is pretty cold, that can be a very inviting environment for mold and rot, so you might benefit from a dehumidifier to help stave off root rot and the subsequent yellow leaves.
I know it sounds counterintuitive, but we use ours all winter and the plants don’t mind.
Old age is another common cause of yellowing leaves
This is fairly self-explanatory, but, weirdly, there are a couple of different reasons why leaves get old.
The first one is, you know, the general passage of time:
The leaf is just…old
This is also super common – leaves don’t last forever.
In my experience, the yellow of old age is much brighter than leaves that are yellowing because they’re stressed.
On the left, we have a Philodendron subhastatum, and on the right is a Philodendron micans. Both of these leaves are putting on a full autumnal display that looks stunning (despite signaling imminent death).
Monstera don’t have quite those reddish tones, but they do go quite a bright yellow.
There’s also another reason certain leaves are…retired, shall we say:
The leaf is too small
Monstera leaves last a very long time (like, years) so this isn’t something that will happen very often EXCEPT when your plant has decided to start putting out big leaves.
Juvenile Monstera only have tiny leaves, but given the right conditions, they can start growing much bigger leaves quite early on.
Due to the growth pattern of Monstera (i.e. up), those older, tiny leaves quickly get shaded out by new growth, plus they’re too small to be able to provide much energy through photosynthesis anyway.
Therefore, in the typical brutal fashion of mother nature, those leaves are basically cut off from any nutrients and left to yellow and die.
Look, I know he’s tiny and useless, but he’s cute! Isn’t that something??
Pests can cause yellow leaves on Monstera
As I mentioned before, most of these points can be applied to most tropical house plants but there are some things that are Monstera-specific, and one of them is thrips.
Now, don’t get me wrong, ANY plant can suffer from a thrips infestation, but Monstera are especially attractive to them for some reason.
Thrips damage can manifest in a number of different ways (you get the whole roster of symptoms - brown leaves, yellow leaves, droopy) but the actual marks the thrips leave are quite distinct.
Firstly, there’s the marks from where the thrips have been sucking – it looks like someone’s taken an eraser to the leave and tried to rub the green off, like this:
And then on the underside, you’ll probably be able to see a load of thrips poop. Yay!
Those little yellow dots? Thrips larvae. Those brown smears? Thrips poop*.
*I assume from the adults. If the babies are producing poop twice the size of their own body I must offer them begrudging applause.
Seasonal changes can cause yellow leaves in Monstera
Monsteras don’t like seasons.
Well, they actually deal with seasons much better than more delicate plants like Calathea. But they’re not very well equipped to deal with them.
Seasons close to the equator are more about changes in rainfall, and winter isn’t really a thing at all.
If your house gets too cold in winter, then your Monstera may go into a kind of dormancy. Monstera aren't meant to go dormant, like plants native to colder climates do - it's more that they reduce their energy expenditure as much as possible so they can concentrate it all on staying alive.
Monstera may drop leaves, but they could also turn yellow first. Make sure you check for thrips though, because they LOVE a cold-stressed Monstera.
Fertilizer issues can result in yellow leaves
Learning how to fertilise your house plants can be a bit of minefield when it comes to information overload. If you’re the kind of person who likes to get it right, I have an article that goes through how to make it as easy or complicated as you like.
(The rest of you, just do your best).
In my experience, under-fertilising is more likely to produce yellow Monstera leaves than over-fertilising.
Not enough fertiliser
Monstera deliciosa don’t seem too fussed about fertilizer – they can do without it perfectly fine and can tolerate the odd accidental over-fertilizing.
HOWEVER, with Monstera adansonii it’s a different story. They are very, very hungry, and show it with yellow leaves.
It looks, annoyingly enough, like thrips damage:
It’s giving off the same ‘attacked with an eraser’ energy.
Definitely check for thrips first BUT I’ve found that Monstera adansonii go from looking totally fine despite being covered in thrips, to being dead. On the plus side though, thrips aren’t as drawn to them, and they’re easier to eradicate (easier, not easy).
Too much fertiliser
Fertiliser burn can look different from plant to plant BUT the one commonality seems to be that the yellow/brown discolouration tends to be concentrated towards the edges of the leaves.
How to tell which nutrient your Monstera is lacking
By the way, this is NOT an exact science:
- Nitrogen – old leaves yellow first, yellow spreads from the inside of the leaf outwards
- Potassium – yellow moves from outer edges in
- Magnesium – veins remain gree, but yellow spreads from inner leaf to edges
- Iron – yellowing of leaf veins
Not all fertilisers are made the same, and many (especially, I’m afraid, the more natural ones) don’t have a complete of the micronutrients that plants need.
If you’re worried that your fertiliser isn’t complete, you can use hydroponic nutrients, which contain the complete profile of macro and micronutrients that your plant needs.
This is especially important if you water using distilled water.
Light issues can result in yellow leaves
Light issues in Monstera tend to show in the size and shape of the leaves – they stay pretty small and don’t develop the fenestrations that we’re all desperate for.
You’ll also notice that the petioles grow very long (because they’re stretching towards the light) and then the leaves weigh down the ends so they look droopy.
However, if you notice that the veining on the leaf is developing a yellow outline, that could indicate that your Monstera needs more light.
Humidity issues can result in yellow leaves
As I mentioned before, Monstera deliciosa aren’t too fussy about humidity, BUT extremely dry air can cause brown spots on the leaves, and then the leaf will eventually yellow and die.
It would have to be really low humidity though, and if your ambient humidity is 40% or above you should be totally fine.
Other Monsteras are a bit pickier about their humidity. Monstera obliqua need humidity levels of 80%+ otherwise they’ll shrivel up and die.
Adansoniis sit firmly in the middle, and like a medium 60% humidity, though they will tolerate lower.
Shock can result in yellow leaves
The reason Monstera leaves go yellow when they are shocked is that the plant is re-evaluating its resources so it can better deal with what happened.
If your Monstera decides it can better cope with the move from the kitchen to the living room if it only has eight leaves rather than ten, it’ll kick two leaves to the curb without hesitating.
No one ever in the world has said that houseplants aren’t dramatic.
It’s pretty easy to shock house plants – even the most innocuous move of two feet from one side of the window to the other can shock them.
Monstera are pretty hardy when it comes to withstanding shock, but there are still a few things you should try to avoid.
Don’t put your Monstera outside in winter. First, the leaves will go yellow, then they’ll go brown, and then they’ll drop off. In quick succession.
Don’t put your Monstera outside in summer without properly acclimating it. If it’s a bit late for that, I have an article on rehabbing sunburnt Monsteras. Just because every leaf has crumbled to dust doesn’t mean that the roots are dead!
Plants don't like moving. Whether it's from pot to pot, room to room, or the garden centre to your house. It's not something they're equipped to deal with.
All you can do is avoid moving your plants as much as possible, and if it’s inevitable give them a little extra TLC once they’re situated again.
Too much water or not enough.
In both cases leaves go yellow before going brown, but underwatered plants go downhill all in one - they're fine for months, and then the next day they're shriveled and brown. They turn yellow for, like, a couple of hours.
Overwatered plants have a slow and steady descent into death, and tend to go from yellow to mushy.
We’ve already covered this, so I won’t go on anymore about it. If you’re worried that you have over-fertilized, your plant may benefit from being flushed.
I’d say that nine times out of ten, yellow leaves are a direct result of being overwatered. Be sure to check your pot size, medium, and that you’re until the soil is dry before watering again.