Why is my house plant dropping leaves?

Why is my house plant dropping leaves?

Ok, first off, let’s stop you panicking. Your plant has lost a leaf. Or several leaves. This does NOT (necessarily) mean that your plant is dead/dying.

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 therefore technically there are things we can do to stop our plants losing leaves unnecessarily.

So, why do plants lose their leaves?

  1. You’ve made a big change to their environment and they are SHOOK
  2. Overwatering. But you knew I was gonna say that, didn’t you?
  3. Underwatering. Yup, and that.
  4. Insufficient nutrients
  5. Its pot is too small
  6. Temperature fluctuations
  7. Low humidity
  8. Pests (they ate a leaf or stem)
  9. Physical damage (you broke a leaf off)
  10. Low light
  11. Plant lifecycle (their leaves are old)

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1 – Big changes to your plant’s environment

Hands up who likes to get a plant home from the nursery and repot it right away?

Yeah, I did too, until I learned that that is a GREAT way to shock the hell out of your plant. To death, in some cases.

So leave your damn plant alone for at least a week before repotting it.

I DON’T CARE FOR YOUR EXCUSES.

I don’t care if the roots are coming through, or the pot is distorted or whatever. Unless the nursery pot is literally on fire, give it a bit of time to acclimatise to its surroundings.

I got a ZZ plant from a popular supermarket chain (Sainsbury’s, British folk. For ¬£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 still waited a week. And it was a ZZ plant. Those things are like the missing link between real and fake plants.

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That was probably the reason I waited to repot, actually. Imagine being the plant blogger that kills a ZZ plant. Anyway. Wait a week before repotting.

Your plant already has to get used to its new environment, which is probably getting less light and less 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 a bit in shock when you buy them.

When you do repot, make sure you use the appropriate potting mix. I’m fairly new to houseplant care, and have only just discovered the evils of house plant potting mix. Sure, your plant will survive, but you’re probably better off making your own potting mix in order to ensure your plant thrives.

There are recipes available online, but most require some mix of perlite, coir (coconut husk), bark and some other stuff, most of which is available on Amazon and will work out cheaper in the long run.

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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 it’s energy into other parts of the plant and something had to give.

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2 – Overwatering

Whatever problem you’re having with your plant, overwatering could be the cause.

The good thing about overwatering is that you could potentially save the leave before it drops off. Watch out for yellowing leaves rather than brown ones, and if you see any, check the soil with a moisture probe.

If you don’t have a moisture probe, gently ease the plant out of its pot and have a look at the roots. If they’re black and slimy rather than white and firm, then you have root rot and have been overwatering or allowing the root ball to sit in water. Remove the rotten parts of the roots (they can’t be saved) and add in some new potting medium if the old stuff is saturated.

Hopefully, if you get to it quick enough you can save a leaf from dropping off if you get to it quickly enough.

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3 – Underwatering

If you underwater a plant, they will start going brown and looking a bit crispy (make sure you’re not confusing overwatering for another issue, like sunburn or nutrient buildup/deficiency).

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.

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.

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4 – Insufficient nutrients

If your plant looks like he’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 if 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 use a liquid seaweed fertiliser personally, that just so happens to be high in nitrogen. I bought it because it’s what Monty Don uses, and if it’s good enough for Monty, it’s good enough for me.

Be careful with fertilising – I use half the recommended dosage about once a month-ish, but I’m human, and therefore usually forget. It’s also far more likely to damage your plants if you overfertilise them compared to if you over fertilise them.

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5 – The pot is too small

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, some plants don’t mind being in a small pot, so do your research on your particular specimen before making your plant move (pothos and succulents, in general, have small root systems so don’t need to be in a very big pot for their size. I recently got a Philodendron Golden Dragon and it’s in a tiny pot in comparison to the size of the plant).

When you go to repot your plant, don’t try to save future you time by potting your plant in the biggest receptacle you can find. Sure, plants like their space, but they could potentially go into shock if you put them in a really big pot.

It’s also a lot easier to overwater your plant if you put it in a pot that’s too big because the soil will hold onto more water.

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6 – Temperature fluctuations

In my experience, plants either don’t seem to give a shit about draughts, 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 draughts. Yuccas are great for patio doors because they don’t mind the cold but they need a lot of light.

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.

Good luck to me and my plants making it through the cold, dark, UK winter.

Oh, and it’s not as easy as just turning up the radiator either – plants that re too near to heat sources can dehydrate and drop leaves. Tis a minefield.

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7 – Low humidity

I’m ‘lucky’ in that I have a fairly damp house. We run a dehumidifier in winter to prevent mould, so I’m hoping that the humidity levels in either the kitchen or office (I haven’t decided where to overwinter my plants yet) will be high enough that I don’t need to worry about humidity.

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.

I don’t have one yet, but it’s at the top of my list.

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8 РPests 

Mealybugs, scale, and spider mites can all cause leaf drop. To treat, wash your plant with warm water and a small amount of insecticidal soap.

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.

My dieffenbachia is currently dying (I have no idea why – it isn’t overwatered or underwatered, it has enough light, it shouldn’t need fertilising…WHAT DO YOU WANT?) and has recently acquired some mealy bugs. I only have two other plants with mealy bugs, and both are in other rooms.

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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.

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 of 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. Spider plant pups, especially, don’t like rooting in soil as much as they do in water.

For plants like Tradescantia and Pothos, you should be fine putting the snapped parts straight back into the soil, as long as there’s a leaf node on it for roots to grow from. Even if there isn’t (or you’re not sure), it’s worth a go.

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10 – Low light

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 or two.

My Tradescantia has gotten long and leggy, so I’ve pruned it a bit and put some of the stragglers back the soil to propagate.

This is a really good way of getting a really full-looking plant, and it works for all kinds of trailing plants like pothos and philodendron.

The only issue is that the lower leaves, closest to the pot can be starved of light, so you may get a few leaves dropping.

It doesn’t really bother me, because the rest of the plant is healthy, and it’s the price you pay for a full plant.

The only thing is that you need to be diligent in remembering to remove all the dead leaves (I’d say on a weekly basis), otherwise you’ll be creating a haven for fungus gnats.

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11 – Life cycle

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
  • The plant may have grown so large that the leaves at the top are blocking light to the ones below, causing them to drop
  • The leaf may be old. It’s old. It’s tired. It’s cells no longer allow inadequate water and nutrition. There’s nothing anyone can do.

monstera leaf

So, how do I determine why MY plant is dropping its 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.

Or, like me and my Dieffenbachia, you’ll never work out the reason why and will have to come to the conclusion that certain plants just don’t like either you, your home, or your other plants.

The annoying thing is, all the articles I’ve read are singing the praises of Dieffenbachia because of how easy they are to look after. I’ve tried everything. I can only assume now that it’s been overwatered¬† (often the case, even in nurseries) and is taking its sweet time to recover. It’s still growing leaves, but the older leaves are going wrinkly (but it’s not thirsty).

Maybe it has some kind of Dieffenbachia-specific disease.

Although I’ve had one before that I actually killed.

The future is not bright for Dieffenbachia in my house.

Sorry guys.

They’re so pretty too.

I’ll sort the mealybugs tonight (preferred method of mealybug removal: remove bugs with tweezers and wash plant with neem oil and insecticidal soap).

I’d be grateful for any suggestions as to how to make my Dieffenbachia happier, as well as any insights anyone has about plants dropping leaves that I haven’t covered. Thanks!

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