Fern fronds turning yellow can be completely normal. New fronds tend to be lighter in color compared to more mature ones. Older fronds that are about to drop off also turn yellow, then brown, due to the normal life cycle of the plant. These older leaves are at the base of the plant. If the fern fronds that are turning yellow are all over the plant, it is probably due to an environmental factor that is causing the plant stress, hence the discoloration.
The most common causes of yellowing ferns are transplant stress, root problems, lack of nutrients, pests, changes in temperature, light problems and watering issues.
Why is My Fern Turning Yellow?
Transplant stress
Ferns can quickly display signs of stress, such as turning yellow or even brown, when they are transplanted. Transplanting can mean either being taken from one location to another or being repotted from one pot to another. The best time to transplant a fern is during the springtime. This season is the mildest of all the seasons and allows the fern to recuperate more smoothly.
If you take the fern from a place where it has grown for months and has the ideal conditions for it to live in, and transfer it to your home where the conditions are less ideal than its natural habitat, the fern will react with signs of stress.
The same will happen if you uproot the plant. Try to cause as little trauma as possible to the roots when removing it from the pot. Make sure the diameter of the new pot is two inches wider than the root system and just as deep. This will help the fern adjust better.
There is really not much you can do while the fern is adjusting to its new home. The yellowing fronds will appear, but as long as you provide the plant with the best care you can, it will recuperate in a short time.
Root problems
A fern can also turn yellow if it has root problems, specifically if it is rootbound in the pot. Being rootbound can also contribute to a plant getting root rot. Severe root rot that has moved up the stem and into the leaves can result in yellowing. If the rot has only affected some of the roots, you can save the plant by cutting off the affected parts. Cut back on watering and change the soil to a well-draining variety. Make sure you transfer the plant to a pot that is big enough for the roots to spread out, so they are no longer rootbound. The pot also needs to have drainage holes at the bottom in order for excess water to flow out.
Lack of nutrients
Your fern could also be turning yellow due to a nutrient deficiency. A lack of nitrogen in the soil can greatly affect the fern, and may cause yellowing fronds. If the tips of the fronds look burnt and brown, it is probably due to too much nitrogen.
You can add nitrogen to the soil by mixing in perlite, pine bark or organic compost. These materials will help keep the soil pH at an optimal level.
Pests
Ferns are susceptible to spider mites, mealybugs and scale insects. Infestation by any of these insects can result in the fronds of the fern turning yellow.
The best way to prevent an infestation is to inspect the plant regularly to make sure there are no pests.
If you do happen to spot these pests, make sure you isolate the plant so that the pests do not spread to your other plants. You can use a cotton pad soaked with alcohol or neem oil to kill the pests on the fern’s fronds. Pesticides are not recommended, because fern fronds can be quite delicate.
It should also be a protocol for you to isolate any new plants for at least a week after bringing them home, so you can properly observe them for pests before placing them anywhere near your other plants.
Changes in temperature
Fern fronds can also turn yellow yellow and even brown if they are left in the cold. This is especially true for outdoor ferns that turn yellow in the winter as they enter dormancy. Indoor ferns do not have this same cycle, though. If the fern is anywhere near a draft, such as an air conditioning vent, the tips of the fronds can discolor.
Ferns prefer temperatures between 65 and 75 degrees Fahrenheit. If the temperature increases beyond this, you will need to water the fern more to keep the leaves from changing color.
Light issues
Ferns do not do very well in full and direct sunlight. They prefer to be in the shade. If the fern is exposed to too much sunlight, the fronds will become yellow. In direct sunlight, fronds can turn brown and become sun damaged. The tips will look scorched and dry.
Even though ferns like the shade, they still need a certain amount of light. Just make sure they get indirect light for small periods throughout the day. A fern kept in a spot that is too dark will eventually wilt and die.
You can toughen the fern by putting it outside in the shade first, and adding more and more time in the sun every day.
Watering issues
Ferns like soil that is always between moist and dry. It can be tricky to find the balance between underwatering and overwatering your fern. Going to either extreme can make the fronds turn yellow and wilt.
The best way to know if you need to water your plant is by looking at the soil. If it is dry, water the fern; if the soil is still damp, wait one or two days and check the soil again.
Conclusion
Ferns can require a little more maintenance and attention than most plants, but having their lush and beautiful foliage in and around your house is worth the effort.
When a fern’s fronds are turning yellow, it usually means there is an environmental factor causing it stress. You will need to identify the problem in order to remedy it as soon as you can.
The most common causes of yellowing ferns are transplant stress, root problems, lack of nutrients, pests, changes in temperature, light problems and watering issues.
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