Staghorn ferns (Platycerium spp.) are frost-tender plants native to the rainforests of the tropics. Growing upon other plants merely for support, these large-growing ferns need bright light, warm temperatures, rainwater and a balanced supply of nutrients from decaying leaf and insect litter that collects in the clumping base of foliage. A popular nutritional supplement often lauded in regions where staghorn ferns grow outdoors year round is the placement of a banana peel in the fern foliage base to provide potassium. Banana peels do not provide all nutrients necessary for good plant growth, however.
Eat a banana and retain the peel.
Toss the entire banana peel into the central core of the fern, into the basin of foliage on the top of the plant cluster. Massive ferns, those wider than 3 feet in diameter, may benefit if two peels are provided. Cut the banana peel with a paring knife into smaller sized pieces to better fit or nestle into the foliage basin if the staghorn fern is small and mounted on a trunk or wood lath plaque.
Allow the banana peel to naturally decay in the staghorn fern. Natural rainfall or irrigation sprinkler spray can continue to shower the fern as the nutrients from the peel are absorbed gradually by the plant.
Supplement the nutrients provided by the banana peel's degradation with a slow-release granular fertilizer that is well balanced, such as a 10-10-10 formula, with micronutrients. Consult the fertilizer product label for a list of micronutrients. Sprinkle 1 tsp. of the fertilizer granules into the foliage basin of the fern. A balanced liquid fertilizer may also be used at half-strength every two weeks to shower the plant foliage.