How to Grow Ferns

Ferns in the wild are found growing in humid tropical conditions as well as high windy mountain slopes and all terrains in between. More than 12,000 species of ferns are known to exist, but there are a few reliable types for home gardeners.

Ferns offer great variety in plant form and size. Sword ferns are robust with straight, pointed green leaflets. Other varieties have rounded, delicate lacy leaflets. The Australian sword fern (Nephrolepis obliterata) and mother fern (Aspleniem bulbiferum) are examples of these two types, and they each do well in U.S. Department of Agriculture hardiness zones 9 through 11 when grown outdoors. Ferns also make excellent indoor plants, where they can be grown across all zones.

There are a few simple guidelines for successful fern growing. Choose a garden area that has full to partial shade. Leaves on delicate ferns such as the ostrich fern (Matteuccia struthiopteris) will burn or shrivel under full sun. Ferns planted under the canopy of a tall tree benefit from the dappled sunlight. The stronger the sun received, the more water will be needed.

Ferns tolerate a variety of conditions but thrive under optimum soil conditions. According to Clemson University Extension: "All ferns prefer well-drained soil high in organic matter."

If the soil condition is too heavy and claylike or too sandy, mix a 2-inch layer of shredded bark or other organic material into the top 10 inches of soil before planting the ferns. Organic materials help retain soil moisture and provide soil structure.

Hold soil in your hand and squeeze gently to determine the soil type. Soil with too much sand will run through your fingers quickly. Soil with too much clay will retain the ball form without changing. Good loamy soil breaks into small clumps and falls out of the hand easily.

Fertilize ferns in the springtime, just after new growth has started. All ferns are sensitive to overstimulation by fertilizers and should be fed with a slow-release, balanced fertilizer. Mix 1 teaspoon to each gallon of water in a watering can or hose-attached sprayer.

Ferns prefer moist soil conditions. Spread a 2- to 3-inch layer of mulch material such as shredded bark, pine leaves or mature compost around the base of each plant, but 2 inches away from the main stem. The mulch layer will help retain moisture and keep the soil cool.

Use a regular watering schedule of once per week during the first year while the plant's root system becomes established. Plants may require additional water during dry times. The topsoil should be moist to the touch at all times for healthy fern growth.

Many ferns, such as 'Silver Lady' (Blechnum gibbum 'Silver Lady') can be grown indoors in the moderate, indirect light of a north- or east-facing window. Direct sun will dry out and damage the leaves. The ideal temperature for indoor ferns is between 60 and 70 degrees Fahrenheit during the day, and about 10 degrees cooler at night. Use a commercial potting soil that is porous enough to allow quick drainage. The soil should be moist to the touch but not soggy. Do not allow ferns to dry out completely.