This post may contain affiliate links. Read the full disclosure here.
Ok, first off, let’s stop you panicking. Your plant has lost a leaf. Or several leaves.
Sometimes plants just lose leaves.
Their leaves get old and they drop off.
That’s just the natural lifecycle of plant leaves.
But there are other things that can cause plants to drop leaves, and there are things we can do to stop our plants losing leaves unnecessarily.
So, why do plants lose their leaves?
- You’ve made a big change to their environment and they’re frightened
- Overwatering. But you knew I was gonna say that, didn’t you?
- Underwatering. Yup, and that.
- Insufficient nutrients
- The pot is the wrong size
- Temperature fluctuations
- Low humidity
- Pests (they ate a leaf or stem)
- Physical damage (you broke a leaf off)
- Low light
- Plant lifecycle (their leaves are old)
1 – Transplant shock
A lot of people like to repot their plants as soon as they bring it home, but I recommend you leave it where it is for a couple of weeks. If you’re worried about pests transferring, keep it in isolation until you’re sure it’s safe.
Being rootbound is NOT a death sentence for your plant. Two weeks of being a bit squished is not going to hurt your plant.
I got a ZZ plant from a popular supermarket chain (Sainsbury’s, £9. Bargain) and it desperately needed repotting.
For those of you unaware of the structure of a ZZ plant, they have tuberous roots that are massive and solid and easily have the power to distort a flimsy supermarket pot so much so that you have to cut the pot to get the plant out.
I mean, LOOK:
I still waited a week. And it was a ZZ plant. Those things are like the missing link between real and fake plants.
Your plant already has to get used to its new environment, which is probably getting less light and lower humidity than wherever you got it from. Except in the case of supermarket plants, which are treated like crap, but they're probably not long from the nursery and are probably still a bit in shock when you buy them.
When you do repot, try to use a decent houseplant potting mix.
How much to add depends on your habits – if you tend to overwater, you can do a 50/50 mix. Use less if you err on the side of neglect.
Why does shock cause a plant to drop leaves?
It could be fluctuations in temperature, light or water, or it could just be trying to put all its energy into other parts of the plant and something had to give.
Shock causes plants to go into survival mode. It only uses as much energy as it has to – any leaf that it doesn’t need will be shed.
2 – Overwatering
Whatever problem you’re having with your plant, overwatering could be the cause.
Leaf drop is a fairly common response to root rot, which is usually caused by a lack of oxygen to the roots. Excessive watering waterlogs the soil, depleting it of oxygen and the roots, er, rot.
It’s honestly impressive just how few roots a plant can have and still not die.
A few months ago I noticed that my Aglaonema looked terrible. Every time she grew a new leaf, an old one would die. She was looking a bit leggy, so I assumed lack of light was the issue. I moved her to a brighter spot and she rallied a bit, but didn’t really bounce back as I hoped she would.
So I decided to investigate the roots. Here’s what I found:
As you can see, we have two cuttings and ONE (1) root.
That…is not enough.
Can she be saved? Absolutely. Will she lose all her leaves? Yes, probably.
As I mentioned earlier, if a plant is short on resources (in this case most of them, because it needs roots to absorb water and nutrients) it will get rid of excess baggage. Leaves may die, but that will mean more energy can be spent on regrowing the roots.
If you see any brown or mushy roots, remove them – even if that means the plant has no roots left.
The plant can regrow them. It has the technology.
If your plant has very few roots, I’d take it out of the soil and rehab it properly. Read this post to learn how to do that.
3 – Underwatering
If you underwater a plant, it will droop, start going brown and look a bit crispy (make sure you’re not confusing underwatering for another issue, like sunburn or nutrient buildup/deficiency).
Here’s a plant doing the droopy (a peace lily, of COURSE:
If you water a plant when it’s at this stage, you shouldn’t have many issues. It’s not *great* to wait until plants droop before watering them, but the plant as a whole will be fine. But you can clearly see a few brown leaves.
The bad news?
Once a leaf (or part of a leaf) has gone brown, it can’t be saved. The brown colour indicates that the cells are no longer able to let water in and hold it. Sorry.
The good news?
If just part of the leaf has gone brown, then you can try trimming it off and seeing if the rest of the leaf remains. It won’t regrow (that I’m aware of, anyway), but it’ll look ok. You can then keep a close eye on the plant and water it when it needs.
Also, the plant will be a-ok. Here she is a couple of hours later:
Bear in mind that plant can vary wildly when it comes to how much water they need.
Alocasia, for example, like to be kept moist, but don’t need watering particularly often because they can retain a lot of moisture UNLESS they’re pushing out a new leaf, in which case they become thirsty, insatiable monsters that will threaten to kill their new leaf if you’re not there in time with the watering can.
If you’re a serial under waterer, then stay away from terracotta pots (they wick moisture away from the soil and it can evaporate out through the porous clay) and alocasia. I learned that the hard way!
4 – Insufficient nutrients
If your plant looks like it’s about to drop a leaf but you think your watering schedule has been keeping on top of its hydration needs, then you may need to have a look at fertilising.
You shouldn’t need to fertilise a plant within the first year of acquiring it, because there should be plenty of nutrients in the soil.
If you've had a plant for over a year, then it's time to fertilise. If your plant is dropping leaves, then it may be deficient in nitrogen. You can either get a balanced fertiliser (with equal proportions of nitrogen, phosphorus, and potassium) or get one with a higher level of nitrogen.
I used to use a liquid seaweed fertiliser. I bought it because it’s what Monty Don uses, and if it’s good enough for Monty, it’s good enough for me.
Recently I started fertilising all my plants with the General Hydroponics Flora series because I don’t have to use a separate fertiliser for the plants I have in Leca.
If you like feeling like a scientist, I HIGHLY recommend this one.
If you just want to pour a bit of fertiliser into a watering can, go for a seaweed fertiliser.
Overfertilising isn't as big of a deal as many people think. I fertilised my plants every time I watered for about three months at the start of th growing season and the only reason I stopped was that their growth slowed. I laid off the nutrients for a couple of weeks, and then fed every other time I watered. My plants are thriving. (Obvs I fertilise differently in winter. Only the plants that are growing get fed, and usually once a month).
Your fertilising schedule is a very personal thing.
I’ve changed up my routine a LOT over the years, so don’t be afraid to chop and change.
I have an article here giving an overview of fertilising as a whole, and this one is a look into the way I fertilise my plants and shows how you can organise your schedule.
Read this article about watering your plants from your aquarium (if you have one), and this one if you have no idea which fertiliser to use.
5 – The pot is the wrong size
If the pot your plant is in is too small, then your pot can become root-bound.
To check this, gently slide your plant out of its pot – a rootbound plant will have roots encircling the inside of the pot, so much so that you may not be able to see the soil.
Rootbound plants can become stunted and drop leaves because the roots can’t support the plant.
Whilst no plant likes being completely root-bound, most plants prefer being snug in their pot. Only up-pot the plant if you can see the roots encircling the pot and the root ball and soil holds its shape when you take them out of the pot.
Even then, don’t increase the size of the pot by more than a couple of pot sizes.
Sure, plants like their space, but they could potentially go into shock if you put them in a really big pot.
Often, you can actually end up overwatering the plant by proxy - plants HATE being in waterlogged soil, and a massive pot can cause this.
6 – Temperature fluctuations
In my experience, plants either don’t seem to give a shit about drafts, or they die as soon as you open one door.
If you want to keep plants by outside doors, then research ones that don’t mind drafts. Yuccas are great for patio doors because they don’t mind the cold but they need a lot of light.
Monstera don't enjoy drafts, but they won't immediately die like SOME plants we know *cough* fiddle leaf fig *cough*.
Tropical plants aren’t overly fond of cold weather, but combat this by slowing way down on new leaves and things and just concentrating on not dying. Houseplants can do ok in cooler temperatures as long they have enough light.
Some plants don't mind the cold AT ALL, as long as they don't get exposed to frost. Succulents and cacti have no problems with a cold snap (rumour has it the drop in temp can help with blooming next season). Orchids and Christmas cactus also need a drop in temperature to get really good blooms BUT its usually enough to just...have it live through winter in its normal spot.
Oh, and it’s not as easy as just turning up the radiator either – plants that are too near to heat sources can dehydrate and drop leaves. Tis a minefield.
7 – Low humidity
I’m ‘lucky’ in that I have a fairly damp house. We run a dehumidifier in winter to prevent mould, but the levels don’t get much lower than 50%.
The only really effective thing you can do to combat low humidity is to run a humidifier. Misting plants can help them stay clean, but it only affects the humidity levels for a few minutes.
It is beneficial to group all your plants together because they’ll create a little humid ecosystem and the water they transpire will make the area more humid.
If you’re not sure how humid your house is to get a hygrometer – you can get them from Amazon for under a tenner. It’ll tell you the temperature of your space and how humid it is.
Common advice is to keep plants in the bathroom to help them maintain humidity BUT remember that bathrooms tend to be pretty cold.
We leave our bathroom window open a lot to combat mould, so it’s too cold for plants in the window. If you have better ventilation than I do, plants that aren’t so fussed about temperature but love humidity, like some types of fern, will be happy in the bathroom.
8 – Pests
Prevention is better than cure though, so get into the habit of cleaning your plant’s leaves. I run mine down with warm water with a bit of neem oil dissolved in it.
It’s also prudent to keep any infected plants away from the rest, although I’ve noticed that mealybugs, in particular, don’t have much interest in healthy plants – they’ll go for one that’s a bit under the weather.
BEAR IN MIND that if you have issues with humidity, light, watering, or your plant is under stress for some other reason, that will DRAMATICALLY increase the chances that pests will rock up.
My Monstera adansonii lost almost all its leaves due to thrips. The thrips sucked the juices out of the leaf, leaving it a husk that quickly dropped off. Repeat until you have an extremely leggy plant.
Here is my Syngonium tri-leaf wonder after a thrips battle:
She is recovering, but it’ll be a while before she’s back to full health.
All you can really do is cut it back hard and start again (luckily the roots were fine and it’s growing back really quickly.
The leaves that don't actually drop off are unlikely to recover completely, so if they look a bit sad, you may be better off snipping them off.
9 – Physical damage
Before you go beating yourself up about your plant dropping a leaf, just check that it hasn’t been involved in some kind of accident. If you’re positive that you’re not doing anything wrong with their care, your plant may have been knocked, bumped into or chewed.
The leaf can even damage itself when it's unfurling. They're very delicate before they've hardened off.
If you notice that part of the stem has been snapped, causing the leaf to drop, all may not be lost. Depending on the type of plant and how quickly you catch it, you may be able to propagate the snapped-off section.
For many plants, you can pop the snapped section back into the mother plant’s soil, and it’ll develop roots. I like to put cuttings (snappings?) in water to make sure that the roots are growing nicely.
In my experience, it’s easier to keep an eye on water propagations, rather than soil propagations, and it can be done pretty quickly. This ctenanthe rooted in a couple of weeks:
10 – Low light
Light is the key to house plants. Since I started using decent grow lights, everything just works so much better.
In extremely basic terms, light is energy for plants, so the lower the light, the less energy the plant can produce. Leaves, if you weren’t aware, take a lot of energy to produce and retain.
Therefore, if the plant finds itself in a lower light situation, it may resort to ridding itself of a few leaves.
If you can get there in time, hopefully, you can get your plant to change its mind and keep the leaf by either moving it to somewhere where it gets more light or getting yourself a grow light.
Plants that have been in low light for a long time may have grown leggy and straggly.
Legginess is a sign of stress, and too much stress leads to leaf drop.
11 – Lifecycle
As I mentioned way back in the beginning, leaves die. It can be for various reasons:
- The plant may be putting all its energy into making new leaves and can, therefore, afford to discard a few old ones
This is really common in plants with really big leaves, such as Monstera.
Often, they’ll have teeny, tiny leaves at the bottom that go bright yellow and then die. The plant is fine, those leaves just aren’t worth having, because they don’t bring in enough energy to earn their keep.
I do love how they go really bright yellow though – like the plant wants them to die, but they can look good doing it. Just LOOK at this Philodendron subhastatum leaf on its way out:
- The plant may have grown so large that the leaves at the top are blocking light from the ones below, causing them to drop.
Some plants, like Monstera, have systems in place to combat this. As the plant matures, it develops splits and holes in the leaves to allow light to get to the lower leaves. The very bottom leaves are still probs gonna die.
Here is my Rhapidophora decursiva demonstrating how harsh nature can be to tiny leaves:
- The leaf may be old. It’s old. It’s tired. Its cells no longer allow inadequate water and nutrition. There’s nothing anyone can do
Happens to us all in the end!
How do I diagnose why MY plant is dropping leaves?
If only it were that easy.
I’m afraid you’ll just have to work your way down this list until you come to the culprit.
To start with, increase the light. My Mars Hydro grow light also provides a bit of warmth, so we can get of two issues in one. The light also can help the plant grow stronger, and fight off pests.
I freaking LOVE that grow light. It has been life-changing for me and life-giving for my plants. Even the plants in my west-facing window prefer it to sunlight. It’s also made no noticeable difference to my electricity bill.
My only issue is that it’s a pain to set up without drilling holes in your ceiling to hang it from, or hacking your own weird set-up. Here’s mine:
How to work out why your plant is dropping leaves
This is the order in which I would check various issues, because it goes from most likely to least likely culprit AND won’t harm your plant (it’ll probs help it)
- Check for pests. Treat if necessary
- Give it more light – this helps with loads of things. Acclimate it – if you just shove it in brighter light it’ll burn
- Check your roots. Are they healthy and firm? Or dry or mushy? Treat the issue. It could be underwatering, overwatering, or an issue with the soil/pot
- Check the humidity. If it’s lower than 50% consider a humidifier or some kind of cloche/terrarium/grow box
- Is it cold? Could you move it/get it a heat mat?
If you go through all these steps and meet the requirements (depending on the plant – some like lower light, other like bright light) then your plant should be healthier.