The Language of Leaves: Why Do Leaves Turn Brown?
Plants are incredibly expressive beings, capable of communicating complex needs to passersby if they only know what to look for. There are many visual communications a plant may utilize, but one of the most common methods of communication regardless of species is browning. Browning can mean a few things but knowing what to look for can be the difference between speaking fluently to your plant and having to guess and check.
First, we always recommend looking at your plants regularly so you can identify signs of discoloration early on. I tend to check in on most of my plants about once a week (twice a week for water-loving plants or plants in 5” pots or smaller). If you’re paying attention you can use these signs to understand what your plant is asking for before anything goes terribly wrong. Below I will briefly describe three common causes for different types of browning on your leaves.
The lowest leaf (or bottom few leaves) have turned light brown and feel flimsy or thin and paper-y. This almost always means the soil has gotten too dry. Plants that are overly dehydrated will start to absorb water from their oldest leaves in an attempt to preserve their newest growth. The newest (top) leaves have been grown strategically to collect the most light in the plant’s current environment so it is extra motivated to keep those alive. If you notice this type of browning: take a photo, remove the brown leaves, and water your plant gently.
Note: check to make sure that your soil is still holding water. Sometimes you can be watering regularly but the soil is overly dry and it won’t absorb water anymore. Test this by watering your plant and collecting the water that comes out the bottom for the first minute in a saucer. If most of the water you’ve poured in is collected in your tray your soil is now hydrophobic and isn’t absorbing water. Soak the planter in water for an hour to rehydrate your soil or repot your plant!
The very tips of the leaves have turned light brown. This is nearly always an early symptom of low moisture. If your plant is a humidity lover like Calathea it either isn’t getting the humidity it needs or the soil has dried out just a touch too much. Take a photo of the plant, then trim the discolored parts of the leaves away (note that on most plants a thin scar line will form wherever it has been cut so do not be alarmed when the brown comes back, you just want to make sure that the browning does not continue to spread beyond the scar line). Next test to see if the soil is dry. If it is dry, water gently; if your soil feels appropriately wet, increase humidity instead. If the brown tips return you can be fairly certain that the variable you didn’t change (humidity or watering) is the cause of the browning.
There are dark brown patches showing up on the leaves. Dark brown discoloration is almost always linked to root distress of some kind. Overly wet or improperly potted plants will start to suffer from root binding or root rot and these dark brown spots are a cry for help. First, take a photo of the brown spots on your plant. Next, inspect its roots. If they have reached the edge of the pot, are still in their plastic nursery pot, or are winding around the planter, it's time for something larger. If the roots look dark, mushy, have an odor, or tear easily, rot has begun and all the damaged roots will need to be trimmed away. If left untrimmed the roots will continue to rot.
Note: be cautious when handling the roots of your plants as some plants are very sensitive and can go into shock. Please ask us for help or drop your plant off for servicing in the shop if you’re feeling uncertain about how to trim or handle your roots.
There is so much more to learn about the many signs that plants give us to show they need something, but armed with these tips you should be able to confidently start noticing and diagnosing some of the most common issues! I’d love to hear about some of the other browning issues you’ve experienced with your plants at home! Leave me a comment below to help me write future content!