Click on images to see larger view
Lemon button fern image by Susan Pelton, UConn
Ferns are non-flowering houseplants that are grown for foliage which can take many forms: from the delicate Boston fern to the tough and leathery fronds of the Bear paw fern. As members of the Polypodiospoda class, ferns are vascular plants that reproduce by means of spores. They have complex leaves that uncoil from fiddleheads into fronds. Although they are native to tropical and sub-tropical rainforests ferns are easy to grow and maintain. Ferns require indirect sunlight, moist soil, and a humid atmosphere.
Ferns prefer potting soil with good drainage and high organic content. A potting mix should have peat moss or sphagnum for moisture retention, sand or gravel for drainage, and sterilized bagged garden loam or potting soil. Add 1/2 ounce of dolomitic limestone to each gallon of soil mix and 1 tablespoon of bone meal or 20% superphosphate. See Potting Media for additional info.
Choose a container with a size proportionate to the plant keeping in mind that most ferns have a shallow root system. A plant is too small for its pot may drown in the excess water held in the soil. There should be roughly one inch of space between the root system and the sides of the container. Ferns may need to be repotted often but wait until it seems overcrowded.
Any pot used should have a drainage hole at the base of the container to remove excess water. Do not put stones or broken crockery into the bottom of a container as a method of drainage. This will actually create an environment where the plants roots will sit in water-logged planting medium. A coffee basket filter placed in the bottom before the soil mix will work well to keep soil from running out of drainage holes.
Another option is double potting. Place the fern and potting mix in a permeable container such as a clay pot and then place that container into a larger pot that has a layer of sphagnum moss that will surround the smaller pot. Keep the sphagnum moist.
Ferns prefer indirect lighting from a north or east-facing window. The intense sunlight from a southern or western exposure may dry out or even scald the foliage. A sheer curtain can reduce light penetration or move the fern far enough from the window to avoid direct sunlight.
Daytime temperatures should average 65-75°F. Nighttime temperatures should be about 10° lower, preferably below 60°F. Higher temperatures may require more frequent watering (see Humidity/Watering).
When temperatures are below 60°F add water only when the soil is dry to the touch. If plants receive too much or too little water, shedding of leaflets will occur. Browning on the tips of the fronds and the yellowing and dropping of interior leaves are all signs of a low humidity. Certain practices, in addition to the double potting mentioned above, can be taken to increase humidity surrounding the plant. See Houseplant Watering Techniques for additional information.
Lined Tray: Place a pebble-lined tray or saucer underneath the pot. Add water to the pebbles maintaining at least ¼” of water at all times. The bottom of the pot should not touch the water in the tray. Sitting directly in water will encourage fungal diseases and root rot. For best results, replace the gravel periodically or wash it thoroughly at three-month intervals to halt the development of algae in the water or on the pebbles.
Misting: Use room temperature water. This is helpful during the winter when heating systems may dry out the air.
Room humidifier: Place a room humidifier near the plant to obtain 30 to 50% humidity within the room or consider placing the plant in one of the moister areas of the house such as the bathroom.
Ferns require little fertilizer unless actively growing in winter months. Liquid houseplant fertilizer should be applied at half the recommended amount. Too much fertilizer will scorch the foliage. Do not fertilize newly divided or repotted plants for 6 months. See Fertilizing Houseplants for additional information.
Ferns will require repotting every few years. Divide overcrowded plants by removing them from the pot then use a sharp knife to cut into the root mass, dividing it into 2 or 3 sections. Repot and keep the soil medium evenly moist and supplying humidity for the first few weeks.
Scale, mealybugs, and spider mites are the most common insect problems. Either hand picking or a hard spray with warm water will dislodge most insects. A cotton ball dipped in rubbing alcohol can be used to carefully wipe foliage. Avoid pesticide use that may damage the sensitive plant. See Insecticides: Low Toxicity Options for additional information.
Popular Houseplant Fern Varieties
Silver brake fern image by Susan Pelton, UConn
Despite good cultural practices, pests and diseases at times may appear. Chemical control should be used only after all other methods have failed.
For pesticide information or other questions please call toll free: 877-486-6271.
UConn Home and Garden Education Center, 2017