Pistils Rx: 5 Reasons your Houseplant’s Leaves are Turning Brown

When we launched Pistils Rx a few weeks back, we got an outpouring of emails and comments from our readers asking plant questions. Thank you all for your photos and for describing your issues in such detail! Of the questions we received, no issue popped up quite as frequently as houseplant leaves turning brown.

There are a multitude of reasons why your houseplants leaves might be turning brown, and just as many ways that browning can present (entire leaves, leaf tips, leaf sides, inside the leaves, lower leaves, upper leaves…). And yes, you guessed it – each of these symptoms can have a myriad of causes, depending on the plant species and how it’s been cared for.

That said, there are a few good rules of thumb to help you diagnose the cause of houseplant leaves turning brown. We’ll use the photos you sent to us and show you what to look for when diagnosing why your indoor plant’s leaves are turning brown.

5 Reasons for Houseplants Leaves Turning Brown

1. Not enough water (or too much!)

   Check out the dry stems and brown lower leaves on the tradescantia ‘wandering jew’ in the photo, above. Dry, brown, crispy, and browning starts at the lower leaves. If this looks familiar, you may well be under-watering your plant. Alternately, over-watering can sometimes present in the same way. This is because overwatering damages roots, inhibiting their ability to take in water and causing symptoms of thirst

   Solution: Trim off brown leaves; they’re not coming back. If entire stems have dried, prune them off and try propagating the ends of pruned stems with stem tip cuttings. Water regularly, and thoroughly, taking care not to over-water.

2. Normal aging or Humidity is too low

   Some plants drop lower leaves as the plant matures. This is especially true on ferns (like this asplenium) and some philodendron species. Just prune the old leaves away, and you should be good to go!
   
   

   Remember; your tropical plants are, in fact, native to the tropics. The tropics are wet and the air is humid! Some houseplant leaves turn brown and crispy when the air in our homes is too dry. This is especially true if your plant is getting a lot of direct sun, or during the winter when heaters are running and drying out the air.

   Solution: Move plants away from heaters. Try setting them on a dish full of pebbles, and putting a layer of water in the pebbles. This helps create ambient humidity. Trim off any dried out leaves.

3. Browning leaf tips
   
   
   
   Browning leaf tip tips are as common as they are challenging to diagnose. This physiological condition can be caused by tainted water, erratic watering (too much, too little, or a combination of both), overfeeding, or a combination of all of these. Plants with long, strappy leaves, like dracena, spider plants and calathea (see photo) are often affected, because water has to make the long trip to keep the cells at the leaf tips well hydrated.
   

   
   Solution: Evaluate your plant care regimen and see which of the above factors is the most likely culprit; adjust as necessary. If the brown tips are causing you grief, trim them back with a pair of clean scissors. Take care to cut just outside the line where the green turns brown; otherwise, you can cause a new brown line to form.

4. Too much fertilizer

   Browning around the sides and tips of leaves is often caused by too much fertilizer. Your plant might also show symptoms of thirst. This is because over-fertilizing damages roots, which in turn affects their ability to take in water, making them act thirsty. Most plants don’t need much (or any) fertilizer over the winter months, and this is when it tends to accumulate and cause leaves to turn brown (like on this natal mahogany, which was fertilized every other week). You might also notice a crusty layer of fertilizer build-up on the surface of the soil.
   
   
   

5. Pests and disease

   This is a tough one, and will be getting its own Pistils Rx post in the future. There are many pests that can infest your houseplants, with scale, mealybugs, spidermites and aphids being some of the most common. Fungus can also attack the roots of your plants, making it show the signs of over-watering (leaf browning and yellowing!). Most pests can be seen with the naked eye, but keep an eye out for brown bumps, white fuzz and webbing on and under your plant leaves. Brown spots in the leaf centers are often caused by pests or diseases.

   Solution: As challenging as it may be, consider disposing of truly infested plants in order to save the rest of your indoor garden. They spread quickly! That said, we use insecticidal soap and neem oil to treat minor pest and fungal problems. Prune back any infested branches of your plant and clip off unsightly brown leaves. Allow the plant to rest and recover and continue to check on the pest issue regularly.