Brown leaf tips don't get the same attention as other common houseplant health problems. That's because the good news is it's often NOT a cause for panic stations. But that doesn't mean they should be ignored either! Plus there is one scary cause that can quickly escalate to a life or death situation, so the sooner you find and fix the cause of brown leaf tips, the better.
I say leaf tips, but browning can also start from margins along the edges of leaves. Leaf tip or edges, it tends to slowly creep inwards, sometimes with a yellow 'halo' around the edges of the browning, sometimes the entire leaf will go yellow, even leading to the entire leaf dying.
When to worry
If the browning is getting worse fast or you're also experiencing leaf drop, that IS something I'd be more worried about. But in most cases, brown leaf tips may NOT be an emergency, but can still be a sign of more serious things to come if you ignore it for too long.
Watch out for wrong cures
Ignoring brown leaf tips isn't ideal, but guessing the wrong cause - and then trying the wrong remedy - can make things MUCH worse. It's well worth getting to the bottom of what's causing them on your indoor plants, and fixing it with the right remedy, so it doesn't turn into something you DO need to panic about. Here are the 7 top reasons for brown leaf tips, what to watch out for and how to fix each cause fast...
Why do plant leaf tips turn brown?
Before we jump in to the common causes and the cures, understanding WHY brown leaf tips happen in the first place explains SO much. It comes down to water. A good 99%+ of water our plants take in via their roots, is 'breathed out' through their leaves - called transpiration - not used for growth (yes, that surprised me too).
That's the way it's meant to work. Water flows in from the roots, travels up the stem, out through the branches, and eventually ends up at the leaf tips last.
But when something's in the way of water getting all the way to leaf tips, the rest of the plant might get what it needs, but leaf tips get left high and dry - and sometimes, brown and dead!
When it comes to working out the cause of brown leaf tips, always start at the source: the roots
If anything blocks or stops roots from absorbing either enough water, or from getting enough water fast enough to keep up with the rate it gets 'breathed out', you can end up with brown leaf tips, wilting or worse. Especially if that 'thing' stopping roots doing their job, is root rot. Then things can get serious fast.
Check the roots first
Since root rot is the scariest possible cause of browning (often combined with yellowing and leaf drop of lower / older leaves first), it's the first thing I check. Left unchecked, root rot can spread fast and kill quickly.
Gently slide the plant out of its pot and check what's going on below the surface. Is the soil wet or dry? Are the pot's drainage holes blocked? Any signs of pests? And most importantly, are the roots okay? If you suspect root rot, here's what to look out for and what to do to fix root rot fast >
The bad news
And I'm sorry to say there's a little bit of bad news before we jump into the common causes and cures for each. Those brown leaf tips are NOT going to fix themselves. Brown tips are dead tips.
It doesn't mean the whole leaf will die, you may be able to save the leaf (and the rest of your plant). But plants don't heal themselves like we do. They just grow a new leaf! The good news is brown leaf tips and edges don't 'take energy' from your plant either, so don't rush to cut them off.
1. Under-watering
Starting with the most obvious and easiest to fix cause first. But keep in mind under-watering does NOT just mean leaving a plant too long between watering. Under-watering can also happen when you don't give it enough water to fully wet all the substrate, causing some roots to miss out altogether.
You DO want to water heavily when a plant needs watering. Always.
Yes, even for succulents and cacti (fun fact, all cacti are succulents). Make sure ALL the substrate is wet, top to bottom. Watering heavily does NOT cause over-watering.
So watch out for both: Watering too lightly, and letting substrate dry out too long between watering. Both can both cause there not to be enough water to make it all the way to those leaf tips, causing them to brown and die, as well as causing roots to dry out and die.
A VICIOUS CYCLE
On top of that, under-watering can start a vicious cycle. Less water reduces photosynthesis, which reduces root growth, which reduces the ability of the plant to take up water. Around we go in (dry) circles. Poor plant :(
CHECK BEFORE YOU WATER!
Just a note on something that might NOT be so obvious. Even though those brown leaf tips might look dry and thirsty, don't take them at face value! Even if a plant is wilting and browning, it does NOT mean you should water it.
Both symptoms can also be a sign of over-watering, pests, root rot, fertiliser burn and more. Look a bit deeper (literally), into the symptoms before you fix them with the wrong cure so you don't make it worse!
2. Fertiliser burn
When it comes to brown leaf tips, fertiliser can be both a cause and a cure. The wrong fertiliser, too much or it, or none at all, can all cause brown leaf tips.
One reason fertiliser might be to blame is because fertiliser is made of salts and one cause of brown leaf tips is a build-up of salts in the soil. It's less likely to happen immediately after fertilising, but over-dosing can be one cause. More common however, is a slow build-up of fertiliser salts in the soil over time.
Drought from under-watering often gets blamed first for dry, brown, dead leaf tips; but high salt levels can also cause what's called physiological drought. The fancy name for when there's no shortage of water, but plants can't absorb or use it.
As salt levels increase in the substrate, water cannot enter the roots, and it can even pull water OUT of roots!
But just because fertiliser is a source of salts, does NOT mean you should starve your plants!
WHY IS PLANT FERTILISER FULL OF SALTS?
Fertiliser is a necessary source of salts. Not the type of salt we add to our food. Nitrogen, potassium, phosphorus, calcium... if they weren't in the form of mineral salt ions, our plants couldn't use them (you'll sometimes hear them called soluble salts or fertiliser salts).
And that's no problem, provided your plant uses everything you give it. But realistically, your plant's needs for minerals will change. Some mineral salts will be left behind in the soil. Plus, water evaporates, but salts don't.
HOW TO GET RID OF EXCESS SALTS IN THE SOIL
The best cure is prevention. Regularly flush excess leftover salts out of the soil. A regular top water with plain water will do the trick if you do it often. Even when you water with fertiliser, if you always water heavily enough so excess water pours out the drainage holes, that also helps flush out leftover excess salts from the previous time you fertilised.
But if your plant's in old soil and/or it's been a long time since you last did a flush water, sometimes the best solution is to start fresh with a repot into new substrate. Sometimes you can see the salt build-up. It's more obvious in semi-hydro substrates like leca, but in organic substrates you might spot a white layer on the top of the soil, or take a look under the pots and you may see it around drainage holes.
If you do see salts building up on the top of the substrate, do NOT water through it! Remove it first as best you can. Also keep in mind the water that flushes out the drainage holes can be high in salts, so you want to avoid leaving that water in saucers or cover pots for plants to absorb back up. Re-using that high-salt water for the next plant can also end up burning roots and killing leaves.
HOW OFTEN TO FLUSH SOIL WITH PLAIN WATER
No matter what fertiliser I use, even the ones that say you can use them every time you water, I suggest an occasional flush water (just with plain water), to help get those excess salts down and out. There's isn't an exact frequency for that. I do it every one to three months myself and just replace one water with plain water, no fertiliser. In older soil it becomes more important to do a flush water more often.
WHEN TO REPOT OLD SOIL
I repot every 1 to 3 years depending on the plant and substrate. Beyond the obvious signs a repot is needed (such as a plant being rootbound or the substrate starting to become hydrophobic causing me to have to water far too often); I repot according to the usual time it takes for the substrate to start to break down to a point it can start causing problems.
For a premium quality substrate high in orchid bark, that's about every 2 to 3 years. For a typical soil-free aroid mix I'll average every 2 years, and for soil-based or peat-based mixes, they go on the repot list every 12 to 18 months.
CHOOSING THE RIGHT FERTILISER
So yes, you should still fertilise your plants. The damage from salt build-up in the soil over time is less harmful to our plants compared to no fertiliser at all! Just choose wisely.
Pick a fertiliser that is complete and balanced. One that provides all 12 essential nutrients, and in the right amounts, so plants get everything they need (and nothing they don't).
And yes, you CAN have too much of a good thing when it comes to fertiliser. Some brands of fertiliser have more than 12 nutrients, but the extra salts may not be essential for houseplants, so it's worth checking the label.
A few common ones to look out for are sodium, nickel and cobalt. Sodium is beneficial for C4 plants, like celery, spinach, sugar beet and turnips. But not indoor plants (for them sodium toxicity can occur even at low levels).
Some plants DO need nickel and cobalt. That includes cereal crops like barley (nickel), and legumes like beans, alfafa and peas (cobalt and nickel). But again, NOT our indoor plants.
For them, even tiny amounts can be phyto-toxic (a fancy name for poisonous to plants). If you've got a plant with dead, brown leaf tips and you DO fertilise, check the ingredients list.
3. Nutrient deficiency
Another fertiliser-related cause of brown leaves and leaf tips is NOT fertilising. Quite a few nutrient deficiencies can show up as browning. This cause is an easy fix: fertilise! A few examples are:
POTASSIUM: burned tips and edges, sometimes with spots under leaves also, usually affecting older leaves first. The rest of the leaf tends to stay green*
NITROGEN: Older leaves affected first, usually with yellowing followed by browning, beginning at leaf tips.
PHOSPHORUS: burned leaf tips and margins, usually in older leaves first.
MOLYBDENUM: Mottled yellowing advancing to brown leaf edges, usually on older leaves first.
CALCIUM: Normally affects new leaves and growth tips first causing yellow or brown spots, advancing to scorched brown leaf tips, sometimes also curled leaf tips and edges.
IRON: Tends to start as yellowing between veins on younger leaves first, advancing to brown leaf tips, sometimes with new leaves turning yellow or white.
*Excess phosphorus can also cause a zinc or iron deficiency which shows as yellowing and browning leaf tips and edges.
4. Tap water
Tap water can be another source of salts in the soil and another common cause of brown leaf tips. And like fertiliser, brown leaf tips caused by tap water is often not instant. The mineral salts and chemicals in tap water can build up slowly over time.
And because most plants don't react quickly, it's easy to think tap water is not the cause as symptoms don't start for some time (although some plants are more sensitive to tap water than others).
Using the same cures as above all help if you suspect tap water is a cause of brown leaf tips, including watering heavily, flush watering, not reusing water that's already drained out of a plant and repotting every 1 to 3 years.
You can also avoid tap water altogether by using rain water or distilled water. Bottled water can also be high in minerals. If if it's tap water or nothing, you can also remove some of the chemicals before you water your plants.
AVOID BORE WATER & SOFTENED WATER
Water softeners often use sodium to soften water, another no for houseplants. Bore water also tends to be higher in salts which can burn leaves.
WHICH PLANTS ARE MORE SENSITIVE TO TAP WATER?
This isn't a complete list, but plants more sensitive to chlorine and other chemicals and mineral salts in tap water include:
African Violet
Calathea
Fern
Maranta
Orchid
Parlour Palm
Peace Lily
some Begonia
Spider Plant
Yucca
Stromanthe and other Prayer Plants,
Carnivorous Plants such as Pinguicula,
Snake Plants and other Dracaenas.
However, over time, all plants can show symptoms as salt levels build up in their soil, slowly burning roots and leaves.
HOW TO INSTANTLY REMOVE CHLORINE FROM TAP WATER
One of the harmful substances in tap water that can harm roots and kill leaf tips is chlorine. Also one that can be removed instantly using a product like Phytology Water Drops.
5. Over-watering
Overwatering and (the scary one) root rot can both cause browning that starts from the leaf tips and edges first, often combined with yellowing, usually of older / lower leaves first, sometimes progressing quickly to wilting and leaf drop or even the entire plant dying.
Over-watering gets blamed for a LOT of houseplant problems. Especially root rot, which can quickly become a death sentence for a plant. But over-watering is NOT caused by watering heavily. When it's time to water, you DO want to water heavily so all the substrate (and all the roots!), get water.
It's watering again too soon - not how much water you give at one time - that is to blame. The main cause of root rot is the bad news combination of both high moisture AND low oxygen. If roots are already weak or damaged from other causes like repotting, salt damage, pests or more, that is the icing on the root rot cake (yuck).
Four ways to avoid root rot
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GOOD DRAINAGE
Make sure your pot has good drainage . Check excess water flows out easily and does not pool in the bottom of the pot. Avoid leaving water in the saucer or cover pot.
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THE RIGHT SUBSTRATE
Pick your substrate based on your plant's needs. Choose a substrate that holds the right amount of water to match your plant's preferences and maintains a good balance of water and air.
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THE RIGHT CONDITIONS
Provide enough light and airflow to help plants 'breathe' so they use up the water in the substrate, avoiding the roots getting waterlogged sitting in water.
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THE RIGHT TIMING
Water again when the plant needs it. Knowing your plant makes all the difference. You might water a Peace Lily or African Violet when just the top couple of cms are dry, but doing the same could kill a cactus.
When roots stay wet too long, the combo of being waterlogged with a lack of oxygen is like putting out a welcome mat for the fungi and bacteria that cause every houseplant hobbyists nightmare, root rot.
Too late? If you've discovered root rot and want to know how to treat it - or you're unsure what to look for - Get the ultimate guide to root rot >
6. Low humidity
Many of our favourite houseplants come from rainforests or subtropical parts of the world where it stays warm, bright and humid all year-round. Even in the 'dry' season in the Amazon rainforest, humidity is still super high, around 77%. The wet season averages 88% humidity!
When the air is too dry, plants lose water faster through their leaves (transpiration). When that happens faster than their roots can replace the lost water, plants end up dehydrated. And because the leaf tips are the last place water reaches as it works its way up from the roots, leaf tips are the first place to brown and die when a plant is dehydrated.
Dry air can still cause leaf death even when a plant is watered perfectly. Especially for plants who are more sensitive to low humidity, like Peace Lilies, Calatheas and Marantas. Just seeing dead leaf tips is NOT a reason to water. Always investigate further first.
Dry air is also why dead, brown leaf tips are more common in winter due to heating drying out the air. And if you're a fan of air conditioning, it can mean dry air keeps going in summer. Poor plants!
But before you assume the worst and buy yourself a humidifier, first get a cheap hygrometer and check your humidity highs and lows.
Why NOT to mist your plants
On the topic of humidity, a quick warning about the common advice of misting houseplants to increase humidity: DON'T
Misting can cause more harm than good
Sure, it can increase humidity, just slightly, and only for a very short time. Despite doing little to help humidity, misting can also cause bacterial and fungal diseases like powdery mildew, stem rot, cause salt deposits to build up on leaves, slow down transpiration and even attract moisture-loving pests like fungus gnats. No thank you.
PS: If you're going to ignore the warnings and mist anyway, do it earlier in the day and make sure airflow is high so water evaporates rapidly off the leaf surface.
7. Temperature highs and lows
Temperature extremes can scorch leaves, which often starts from the tips and edges and moves inwards, leaving brown, dead leaf tissue behind. Since plants tend to play the long game, you might not see the effects of temperature shock right away, so think back further than just a day or two for possible temperature extremes.
Maybe your plant was in the path of the air conditioning or heater. Could it have been a cold draught from a window or door left open. For a plant not used to it, direct sunlight can also scorch leaves. Even a sudden temperature drop or increase from a particularly cold night or hot day could be to blame.
After all those scary causes, the good news is most reasons for dead, brown leaf tips are not an emergency. Now you know what to look for, you can work through this list and rule them out until you find your culprit. And more good news is once you find the cause, the cure is normally easy too.
Happy growing,
Anna
ABOUT THE AUTHOR: Anna is the owner of plant store Love That Leaf which specialises in products and advice for indoor plants. She is also the resident writer for NZ Gardener magazine on the topic of indoor plants. You'll see her houseplant care articles in-stores and online on Stuff, The Post, NineHoney and more.