Plant maidenhair ferns in a sheltered, shady location with rich soil. Work aged compost into the soil before planting, to improve nutrients and drainage, if necessary. If the maidenhair ferns are already growing in a location, add compost over the soil surface, but do not mix the compost into the soil because you may damage fern roots.
Mulch the soil around ferns with pine needles or shredded pine bark to prevent weed growth and keep the soil moist. Keep about 2 inches of mulch over the soil, replenishing the mulch yearly with fresh materials.
Water ferns if less than 1 inch of rain falls within a one-week period. Ferns require evenly moist soil to thrive.
Fertilize maidenhair ferns in the spring after the ferns begin growing again. Sprinkle a granular, balanced fertilizer over the soil surface around the ferns, following package recommendations for the size of the growing area. Water the soil well immediately after adding the fertilizer to the soil to help dissolve the fertilizer into the soil.