Ferns are beloved amongst houseplant owners for their bright green fronds, which extend outwards at every angle to beautiful effect. Ferns come in a variety of cultivars and are native to a wide range of forest environments around the world.
While most indoor fern cultivars are tropical and require warm, humid environments, others originate in non-tropical climates, are cold hardy and can take drier conditions.
It is important to understand what your fern’s native habitat is in order to understand what environment you should be trying to recreate with your care.
This will help you to address and solve problems, like brown crispy fronds and leaves, should they arise.
Why is my fern crispy?
Fern fronds and leaves become crispy and dry when the plants are kept in an environment without enough humidity. Fern leaves will also become crispy if they are regularly exposed to too much direct sunlight or are underwatered.
Insufficient humidity
Most fern varieties grown as houseplants are native to the tropics and therefore require high levels of humidity and a warm environment. The famous Boston fern, for example, is native to northern South America.
While it is necessary to maintain high humidity levels in the air around ferns throughout the year in order to avoid fern leaves from drying out and curling up, it is particularly important to do so at the end of the growing season, as autumn turns to winter.
If you have just turned on the radiator in a room in which you are growing an indoor fern, make sure you take steps to compensate for the dry air created by indoor heating.
If a fern has been living outside during the warmer months but has been moved indoors for the winter, pay close attention to how it reacts to the change. Indoor air is frequently drier than outdoor air, so make sure you have a plan in place to reduce the effects of dry air.
If you have the financial means to do so, you can invest in a humidifier. This is the ideal solution and will enable you to make sure that the humidity around your fern is the right level at all times.
However, because humidifiers can be fairly expensive, you might opt for other, cheaper solutions.
You can make a homemade humidity tray by filling a drip tray with clay pebbles or gravel and then filling it up to just below the top with water.
Place the fern on the water-filled tray of clay pebbles. Make sure that the fern is not absorbing the water from the humidity tray by placing it on another, smaller drip tray, or by keeping it in nursery pot inside a decorative pot with no drainage hole.
As the water evaporates, it will increase the humidity around the fern’s foliage.
Misting is another good way to increase the humidity around your plant. Mist early in the morning and keep your misting to every other day at most.
Use lukewarm water to avoid shocking the plant. Be aware, however, that if water droplets are sitting on the leaves too often, it can cause a fungal fern disease known as foliar leaf spot to develop.
Another cost-effective method for providing your fern with a humid environment, is to keep it in a bathroom with a shower. Ferns love a damp, warm environment, so a bathroom can often be an ideal home for them.
Ferns with more substantial leaves, such as rabbit foot’s ferns are better at dealing with drier conditions than fine-leaved ferns, like asparagus or maidenhair ferns.
While it is important to mitigate the effects of indoor heating and to keep your fern well away from any radiators, it is equally important that the environment ferns live are not made to live an environment that is too cold for houseplants, as this can cause ferns’ leaves to wilt.
Too much sunlight
Ferns are native to forests, which means they are accustomed to growing under the cover of a substantial canopy. While they are still happiest when they are exposed to a good amount of light, they prefer bright, indirect light to direct sunlight, which can cause leaf burn.
If ferns regularly receive too many hours of direct sunlight, their leaves will brown at the edges, curl and become crisp. When coupled with underwatering, this can lead to serious drying and crisping of its fronds.
Once fronds and leaves have become brown and crisp to the touch, they will not recover and are only taking energy away from the healthy fronds. You should snip them off and compost them.
If your fern looks seriously damaged, read up on how to revive a dying fern.
Too little water
Most ferns are happiest in soil that is consistently gently moist and is not allowed to dry out completely before the next watering. If tropical fern cultivars are left in dry soil for too long, their fronds will begin to show signs of damage and will become brown and crispy.
Waiting too long before watering your fern will stress it out. Do not allow the top of the soil to dry completely before rewatering. If it is dry, you have waited too long. Instead, try to water it regularly and generously.
Be careful that you do not overwater it either, however, and make sure your fern is not sitting in water-logged soil. This can lead to root rot, and a whole host of other problems.
Use room temperature water to water ferns. The best way to water your fern is to use rainwater. Once you have collected it, bring it indoors and let it sit for twenty-four hours before using it.
This will flush out the salts and harmful minerals that come in tap water, often referred to as “hard” water, from the soil of your plant, and will ultimately leave it healthier and less susceptible to all problems, including crispy leaves.
While it is a good rule of thumb that ferns like consistently moist soil, be sure to check whether your fern really does! There are a few varieties, such as bird’s nest ferns, rabbit’s foot ferns and brake ferns that are relatively cold hardy and like their soil to dry out a bit before being watered again.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.