Ferns are among my favourite plants, and over the years, I’ve grown many different varieties. While ferns are often considered finicky and difficult to care for, I’ve discovered that their needs can vary significantly depending on the type. Some ferns are surprisingly low-maintenance and resilient plants, while others seem to struggle and die without clear reasons.
So if you’ve been asking yourself why your fern is dying and struggling with brown leaves, this guide will help you solve these problems and restore your plant to a lush, green state.
Why Does Fern Have Brown/Yellow Leaves and How to Solve
The main symptom of a dying fern are those shrivelled, brown fronds. Let’s have a look at the causes and how to solve them.
Overwatering
This is probably the reason your plant is dying; the vast majority of brown leaves and plant deaths are usually due to overwatering. If the plant has brown, squishy, or soft leaves, this is likely a sign of overwatering. Consider the soil condition: is it damp? Is the plant in a dark location? These factors suggest that overwatering is probably the issue. If you have fungus gnats around your plants, then this is another sign that the soil may be too moist.
Let’s apply this to one of my ferns that’s struggling. It’s placed at the back of a room, far from any windows, making it quite dark. As you can see, the soil is quite moist. There’s also a lot of browning and dying of the leaves. This all suggests that overwatering is the issue—too much water for too long in this pot.
If you think you are overwatering, there are a few things you should do. First, make sure your potting mix is suited to your plant. Ferns prefer to be consistently moist—not too dry, not too wet—and need good drainage and aeration. I have a homemade potting mix that works well for me if you’d like to check it out.
If your mix is good, the next thing to look at is lighting. Ferns tend to do well in lower light conditions, which can make them more susceptible to overwatering. If possible, move them to a slightly brighter area, especially if you are trying to recover them from overwatering. More light will encourage growth, leading the plant to absorb more water. If the plant is kept in a dark location, then we will need to reduce the watering a lot.
Finally, review how often you water. Assuming you have a good potting mix and lighting, you can water roughly once a week in summer or every two weeks in winter. It’s always a good idea to check the soil with your finger before watering. Stick it an inch in; if you feel moisture, wait a few days and check again before watering.
In their natural environment, ferns typically grow underneath large trees, which help absorb excess water. In pots, they lack this natural drainage system and must handle excess water on their own, which is why proper drainage and a good watering routine are crucial.
Underwatering
Another reason for brown leaves is underwatering. While most plants often wilt when underwatered, ferns are more subtle. They will slowly lose their vibrant colour and develop brown tips that gradually expand along the fronds. If the fronds are crispy and crunchy when touched, if the soil is dry, and if the location is quite light, these are signs that underwatering could be the issue.
Once again, we need to consider the three main factors: soil, lighting, and watering frequency. A good-quality potting mix should retain moisture while also being well-draining and aerated, which will help with both underwatering and overwatering issues.
If your plant is in a bright location, it will grow more and thus need to be watered more often. However, with a potting mix that retains moisture well, this frequency will be reduced. I aim to water every week or two, checking the soil before adding more moisture.
You can also add some sort of mulch on top of your soil like peat moss which will absorb moisture and prevent evaporation from the soil.
By managing these three factors—soil, lighting, and watering—you will be on your way to maintaining a healthy plant, and brown leaves should become a thing of the past.
Too Much Light
Ferns are typically found under the canopies of larger trees and generally prefer shadier conditions. They can tolerate dappled light or bright light through a window, depending on the species. Sun damage appears different from the dry, crispy leaves caused by underwatering, but both issues could be present if the fern is in a very bright location.
Sun-damaged leaves often have distinctive scorch marks on the fronds, especially if this is the first symptom before the fronds brown and dry up. As the plant loses moisture and dries out, the leaves can become crispy and crunchy to the touch, which is because because there is not enough moisture around the roots.
A window usually dilutes the light enough to prevent browning, but if you live in a very warm, sunny climate or if the window receives a lot of direct sunlight during the day, it might be better to move the fern to the side of the window or further away, about 1 meter (3 feet).
Your fern like most other plants will adapt to the light that’s provided to it, so once you have a spot that it’s flourishing in, try not to move it.
Pest Infestation
Sometimes pests can cause brown or yellow leaves on your ferns. Common culprits include spider mites which can be spotted by their tiny webs on your plant, though in my experience, I tend to get scale insects more often. These pests suck the nutrients from the plant, causing the leaves to discolour and die off.
It’s relatively easy to identify this problem by taking a quick look at the fronds. Scale insects are quite obvious, appearing as small white or fuzzy spots on your plant. You will also notice shiny or oily leaves that are sticky to touch.
The solution is usually the same: apply a white oil, also known as horticultural oil. Neem oil is another option, if you want something more natural. Mix the solution according to the manufacturer’s instructions. I recommend taking the plant outside and spraying it thoroughly until the leaves are dripping, paying special attention to the undersides of the leaves and low on the stems where pests often hide.
In a few days, you should notice that the scales have turned brown, which means they are dead. You can then trim off the damaged fronds, or if the damage isn’t too severe, you can leave them in place.
Nutrients
Sometimes, your plant’s leaves may turn brown or yellow due to a lack of nutrients. Other symptoms might include slow or stunted growth. If you notice that the smaller, younger leaves near the bottom of the plant are yellowing while the new leaves on top remain green, this is likely a sign of nutrient deficiency. The plant is prioritizing the available nutrients for the newer leaves at the top, where growth is more important because this part of the plant receives the most light.
Nitrogen deficiency often leads to yellowing of older leaves, as the plant moves this vital nutrient to the newer growth. Potassium deficiency can cause browning at the edges of leaves, while magnesium deficiency might result in yellowing between the leaf veins.
I like to fix all the potential deficiencies at once because if you’re deficient in one nutrient, it’s likely that other nutrients are also lacking. I recommend repotting the plant in fresh potting mix, which will restore essential nutrients. You should fertilize every other week during the growing season, which occurs in the warmer months.
Choose a balanced fertilizer or one specifically designed for your plant type to provide the right mix of nutrients. I like to use liquid fertilizer cause its easier to mix it in when you are doing your watering. Remember, over-fertilizing can also harm your plant, so follow the instructions on the fertilizer package carefully.
Disease
I find ferns pretty resilient to diseases in general but you may sometimes get them. Some common diseases include:
- Leaf Spot Diseases: Fungi create brown or black spots on fronds.
- Rusts: Fungi cause brown or orange bumps on fronds.
- Powdery Mildew: Fungal coating turns fronds white, then brown.
- Bacterial Leaf Spot: Bacteria cause brown or black spots with yellow edges.
- Bacterial Blight: Bacteria create brown, wet spots on fronds.
The best way to fix or prevent diseases in ferns is to improve air circulation around the plant and avoid watering from above to keep the leaves dry. During watering, check the fronds for any signs of disease and remove affected ones before they spread.
You can use fungicides or other chemicals if needed, following the directions on the package, but I find that good ventilation and removing any diseases fronds does the trick for me.
Low Humidity
People say low humidity can cause brown leaves, it’s hard for me to verify because I live in a very dry climate with no humidity at all most of the year. In my experience this is often much less important if not at all compared to your watering regime. Plants are quite adaptable and ferns are no exception and they can thrive in areas with no humidity.
Humidifier
If you are really looking to give the that extra edge then getting a humidifier can be an good choice. Keep it away from the walls so you don’t get mould growing on them and ideally you would want one in every room you keep plants. Alternatively you can keep you ferns in places that are naturally more humid like the kitchen or bathroom.
Grouping
Grouping your plants together can increase the humidity in the area, as each plant traps moisture beneath its leaves, creating a micro environment similar to a forest but on a smaller scale. Additionally, grouping plants creates a lush, cohesive look that will enhance the appearance of your indoor garden.
Pebble Trays
A common suggestion for increasing humidity is to use trays filled with pebbles and water. As the water slowly evaporates, it adds moisture to the air, which can help boost humidity. This method probably works to some degree but its impact is likely minimal and will be quite labour-intensive, especially with many plants, as the trays need frequent refilling.
For a more effective and convenient solution, consider using a humidifier, grouping your plants together, or a combination of both.
Age
Plants generally drop old foliage as they get older to make way for new, healthier growth which can produce energy better for them. If you notice an older, mature frond yellowing, browning or losing all its foliage, this can be a natural process. If you compare it to other fronds on the plant that are still healthy then its a clear sign of just an old frond.
You can go ahead and cut any brown or dead fronds off, I do it all the time. The plant will grow new fronds back even if it has no fronds left at all.
FAQ
Will Ferns Come Back?
Yes ferns despite being very finicky are also very hardy. In my experience even if a fern looks dead with no foliage on it, it’s possible it will regrow new fronds and recover.
How Can I Make My Fern More Bushy?
To get a bushier fern, ensure it’s receiving enough light and keep the soil consistently moist. Rotate the plant every time you water it to promote even growth; the side facing the light will grow more vigorously than the darker side.
Trimming off older fronds at the base can also stimulate new growth. You can also use a liquid fertilizer every other time you water. It doesn’t need to be very strong, as ferns don’t need a lot of nutrients and can be harmed by fertilizers too high in nitrogen. Look for a fertilizer specifically made for ferns or one with appropriate ratios listed on the packaging.
Conclusion
Maintaining nice looking ferns can sometimes be a bit of a pain, but with the right knowledge and attention to their specific needs, these plants can thrive. Understanding the causes behind issues like brown or yellow leaves and addressing them through proper watering, lighting and using a good potting mix will help you maintain healthy, vibrant ferns.
The key is to give them the right conditions, monitor and make adjustments as needed. With time, you’ll find that ferns are not only pretty hardy but also quite easy to grow. They make a great addition to any space and can help tie a display together.
